Pharmacology Past Paper Questions PDF

Index Pharmacokinetics - Page 1 Pharmaco-dynamics - Page 45 Clinical-Trials - Page 86 Parasympathetic System. - Page 97 Sympathetic System - Page 122 Previous Year Questions (ANS Pharmacology) - Page 161 NSAIDs - Page 190 Gout,Rheumatoid Arthritis - Page 204 5-HT, Histamine, and PGs - Page 230 Previous Year Questions (Autacoids) - Page 262 Diuretics & Anti-diuretics - Page 282 Previous Year Questions (Renal Pharmacology) - Page 319 Dyslipidemia - Page 329 Arrhythmias - Page 341 Anti-hypertensives - Page 362 Anti-Anginal Drugs - Page 411 Heart Failure Drugs - Page 423 Previous Year Questions (CVS Pharmacology) - Page 443 Sedatives and Hypnotics - Page 482 Anti-Parkinsonians Drugs - Page 502 Anti-Epileptic Drugs - Page 516 Antipsychotic Drugs - Page 541 Alcohol & Opioids - Page 597 Previous Year Questions (CNS Pharmacology) - Page 616 Antithyroid Drugs - Page 654 Antidiabetic Drugs - Page 685 Corticosteroids - Page 724 OCPs, Osteoporosis, and Sex Hormones - Page 729 Previous Year Questions (Endocrine Pharmacology) - Page 768 Cell Wall Synthesis Inhibitors - Page 797 Protein Synthesis Inhibitors - Page 818 Quinolones and Antimetabolites - Page 833 Antitubercular Drugs - Page 848 Anti Viral Drugs - Page 881 Anti Fungal Drugs - Page 889 Anti Parasitic Drugs - Page 898 Index Anti Malarial Drugs - Page 923 Anti HIV Drugs - Page 934 Previous Year Questions (Antimicrobials) - Page 949 Drugs Acting on Respiratory System - Page 981 Previous Year Questions (Respiratory Pharmacology) - Page 1004 Drugs for Peptic Ulcer Disease - Page 1015 Anti-emetics, Anti-diarrheals, Laxatives and Purgatives - Page 1033 Previous Year Questions (GIT Pharmacology) - Page 1046 Drugs Affecting Blood Flow - Page 1058 Drugs Affecting Blood Cells - Page 1101 Previous Year Questions (Drugs Affecting Blood and Blood formation) - Page 1116 Cytotoxic Drugs - Page 1131 Immunosuppressants and Immunomodulators - Page 1164 Previous Year Questions (Anticancer Drugs ) - Page 1205 Local Anaesthetics + General Anaesthetics - Page 1224 Pharmacokinetics 1. A 30-year-old pregnant woman, currently at 22 weeks gestation and with no known health issues, is planning a trip to Mozambique to visit her grandmother. During a prenatal check-up, the doctor prescribed mefloquine, a drug with high protein binding, for prophylaxis. What effects can be anticipated after the ingestion of this drug? (or) Which of the following will be expected after the ingestion of mefloquine considering its high protein binding property in serum? A. Decreased glomerular filtration B. High volume of distribution C. Shortened duration of action D. Decreased drug interaction ---------------------------------------- 2. What will be true regarding the termination of action of Paracetamol? (or) A 22-year-old female presents with fever and cough for four days. The cough produces yellowish sputum, and she has no chronic illnesses. Respiratory auscultation reveals bilateral coarse crackles. She took paracetamol for fever relief. If used therapeutically, what's true about the drug's termination of action? A. Paracetamol must only be excreted from the body to terminate its action B. Metabolism of drugs always abolishes their pharmacologic activity C. Hepatic metabolism and renal excretion are the two most important mechanisms involved D. Distribution of the drug out of the bloodstream terminates its effects ---------------------------------------- 3. A 33-year-old man complains of shoulder pain for four days, worsened by movement and preventing arm lifting. Abduction exacerbates the pain. He's otherwise healthy and stable. Given the option of oral medication, which drug is most likely to be absorbed effectively from the stomach mucosa? (or) Which drugs have the maximum absorption from gastric mucosa? A. Morphine sulfate B. Diclofenac sodium C. Naproxen D. Aspirin ---------------------------------------- 4. A 22-year-old male with sneezing, coughing, and shortness of breath for two weeks, worse in the morning and at night, presents to the physician. Bilateral wheezes are heard on auscultation, and various drug treatments with different administration routes are being considered. Which statement about the routes of administration in this patient is true? (or) 1 A patient had shortness of breath and bilateral wheezes. Which of the following statements is true regarding the drug administration routes in this patient? A. Intravenous route should be avoided due to the risk of exacerbating wheezing symptoms. B. Subcutaneous route is preferred for immediate relief of symptoms due to its rapid onset of action. C. Oral route is contraindicated as it may worsen the patient's symptoms of sneezing and coughing. D. Inhalation route is the most appropriate choice for delivering bronchodilators to relieve wheezing and shortness of breath. ---------------------------------------- 5. A 23-year-old male with a sore throat, cough, headache, and runny nose is prescribed amoxicillin-clavulanic acid. What primarily determines the maintenance dose of the medication for this patient? (or) The maintenance dose of the drug primarily depends upon which of the following? A. Volume of distribution B. Protein binding affinity of the drug C. Lipid solubility D. Clearance of drug ---------------------------------------- 6. Which drug's poisoning causes an altered state of consciousness and hypotension, and needs to be treated via alkaline diuresis? (or) A 33-year-old man arrives in the ER in an altered state after a suicide attempt with medication. He's dizzy, slurring his words, and has low blood pressure. The doctor plans to start alkaline diuresis. What caused his condition? A. Morphine B. Amphetamine C. Phenobarbital D. Atropine ---------------------------------------- 7. A 34-year-old man arrives at the ER after a car accident, confused but stable. He has swelling on his forehead and a CT scan shows intracranial bleeding. The doctor gives him thiopentone to reduce pressure in his brain. Why does this drug work so quickly but only lasts for about 15 minutes? (or) Thiopentone acts at the CNS within 15 seconds but is active only for up to 15 minutes. What is the reason for this mechanism of the drug? A. Marked redistribution due to high lipid solubility B. Marked redistribution as it contains weak electrolytes C. Marked redistribution due to high plasma protein binding D. Marked redistribution due to high water solubility Page 2 2 ---------------------------------------- 8. A 52-year-old with severe right-sided flank pain was treated with tramadol, a weakly basic drug, which relieved his pain. An ultrasound revealed multiple calculi in his right kidney. What's true about the drug in this case? (or) Which statement is true regarding tramadol? A. It is bound primarily to plasma albumin B. It is excreted faster in acidic urine C. It is highly ionised in the intestinal secretions D. It is absorbed mainly from the stomach ---------------------------------------- 9. Which of the following statements about drug metabolism phases is true? A. At the end of phase I, all the drugs become water-soluble. B. Most common phase II drug metabolising reaction is glucuronidation. C. Function of phase I reactions is to attach a conjugate to the drug molecule. D. At the end of phase II, all the drugs become lipid soluble ---------------------------------------- 10. A 43-year-old man complained of headaches and neck pain for two months, with no other health issues reported. His blood pressure is 160/100 mm Hg. After a physical exam showing no abnormalities, the doctor prescribes a prodrug that acts for 24 hours. What drug was prescribed? (or) Which pro drug exerts its action for 24 hours? A. Metoprolol B. Enalapril C. Telmisartan D. Amlodipine ---------------------------------------- 11. A 16-year-old girl with breathing issues was given IV corticosteroids. Looking at the plasma concentration-time graph of the drug, what's true about its kinetics? (or) Which statement is true about the kinetics of the equation depicted by the plasma concentration-time graph? Page 3 3 A. Half-life is less at low concentrations and more at high concentrations B. Most drugs follow zero-order kinetics C. Clearance is less at low concentrations D. The rate of elimination is proportional to plasma concentration ---------------------------------------- 12. A 42-year-old man has foot tingling, a pale skin spot on his knee, fever, tiredness, and discomfort. The spot is less sensitive to touch and pinpricks. A biopsy confirms the condition. The doctor plans to prescribe a drug that may change dosage needs by inducing microsomal enzymes. What's the drug linked to the patient's condition? (or) Which of the following is an enzyme inducer? A. Ciprofloxacin B. Isoniazid C. Ketoconazole D. Rifampicin ---------------------------------------- 13. Aspirin follows zero order kinetics, at higher doses. This indicates which of the following properties? A. Half-life is constant B. The rate of elimination is dependent on plasma drug concentration C. Clearance decreases with an increase in plasma concentration D. Majority of the drugs have similar characteristics ---------------------------------------- 14. Warfarin is an anti-coagulant medication with a low distribution volume, indicating which of the following? (or) Warfarin has a low volume of distribution, indicating which of the following? A. The drug has a longer half-life B. The drug has low bioavailability Page 4 4 C. The drug has low efficacy D. The drug is not extensively distributed to tissues ---------------------------------------- 15. Which route would the doctor prefer to give the medication such that he can ensure 100% bioavailability? (or) Which route would a doctor prefer to give a patient for 100% bioavailability? A. Intravenous B. Oral route C. Intramuscular D. Sublingual route ---------------------------------------- 16. The drug nitroglycerine, if given via which of the following routes, will have a high first-pass metabolism? (or) By which route will nitroglycerine have a high first-pass metabolism? A. Oral B. Intravenous C. Sublingual D. Subcutaneous ---------------------------------------- 17. Which of the following statements about the given plasma concentration curve is correct? (or) Which statement about the given plasma concentration curve is correct? A. Tmax of the drug is 3 hours B. The Cmax of the drug in this graph is 100 mg/dl C. The area under the curve is the extent of absorption D. The graph can be used to calculate ED50 Page 5 5 ---------------------------------------- 18. Which of the following factors is affected by the bioavailability of the drug? (or) Which of the following factors is affected by the bioavailability of the drug? A. Half-life of the drug B. Volume of distribution C. Dose of the drug D. pKa value ---------------------------------------- 19. A 48-year-old male reports palpitations and headaches for three months, without any other health issues. His vital signs show a heart rate of 111 beats/min and blood pressure of 165/100 mmHg. Atenolol is prescribed to manage symptoms without needing therapeutic dose monitoring. What's true about therapeutic drug monitoring (TDM)? (or) Which statement is true regarding therapeutic drug monitoring (TDM)? A. Done when the clinical response can be easily measured B. Done for wide therapeutic index drugs C. Atenolol is an example of a drug for which TDM is done D. TDM can be done if the drug has erratic pharmacokinetics ---------------------------------------- 20. Which of the following drugs is given by the route shown in the figure? A. Filgrastim B. Insulin C. Tetanus toxoid D. BCG ---------------------------------------- 21. A 53-year-old man complains of cough, weakness, and fever for four days. Pneumonia is diagnosed, and gentamicin is part of the treatment plan. Gentamicin has a half-life of 2-3 hours but can accumulate in the kidney with prolonged dosing, leading to a prolonged half-life of 53 hours. What type Page 6 6 of half-life is this? (or) When gentamicin is given, its half-life is 2-3 hours. However, its half-life is prolonged to 53 hours if it accumulates in the kidney. This type of half-life is called: A. Secondary half-life B. Terminal half-life C. Zero-order half-life D. First-order half-life ---------------------------------------- 22. A 45-year-old male patient presents to the emergency department with ST-elevation myocardial Infarction. The attending physician immediately started treatment with aspirin, propranolol, clopidogrel, and atorvastatin. Which of these are metabolized by CYP2D6? (or) Which of the following are metabolized by CYP2D6? A. Propranolol B. Warfarin C. Atorvastatin D. Clopidogrel ---------------------------------------- 23. Metabolism of drugs occurs in the liver in 2 phases. The first phase involves catabolic reactions, and the second phase involves synthetic reactions that increase drug elimination. Which of the following reactions is a phase 1 reaction? (or) Which of the following is a phase 1 reaction of drug metabolism? A. Hydroxylation B. Methylation C. Conjugation D. Acetylation ---------------------------------------- 24. A 15-year-old girl arrived at the ER after ingesting 15 tablets of an unknown drug, causing altered mental status, rapid breathing, and vomiting. To treat drug toxicity, various methods can remove the drug from the body, such as dialysis. Which drug, when toxic, is eliminated through urine acidification? (or) Which of the following drugs, when in toxic levels, is removed faster through acidification of urine? A. Salicylates B. Barbiturates C. Amphetamine D. Methotrexate Page 7 7 ---------------------------------------- 25. A 45-year-old man with asthma was admitted to the hospital for breathing problems and coughing. He was given two drugs, A and B, intravenously every 24 hours for 6 days. What does the graph showing the concentration of these drugs in the blood over time reveal? (or) A male has been given drugs A and B by intravenous bolus every 24 hours for 6 days. A graph is plotted between the time duration and concentration of the drugs in blood. What is depicted in this graph? A. Drug A does not maintain persistent therapeutic levels when administered every 24 hours B. Drug A exhibits cumulative properties C. Drug B is non-cumulative when administered every 24 hours D. Drug B is destroyed in less than 24 hours ---------------------------------------- 26. A 50-year-old male underwent orthopedic surgery a few days ago. He has been given a transdermal patch of fentanyl for postoperative pain relief. Which of the following is the advantage of transdermal application? (or) Which of the following is the advantage of transdermal application? A. They avoid the hepatic first-pass metabolism of the drug B. They produce high peak plasma concentrations of the drug C. They produce fluctuating plasma concentrations of the drug D. The transdermal route is employed for water-soluble drugs ---------------------------------------- 27. Which of the following drugs has the highest volume of distribution? (or) Which of the following drugs has the highest volume of distribution? A. Haloperidol B. Gentamicin C. Heparin Page 8 8 D. Chloroquine ---------------------------------------- 28. A 40-year-old man comes to the outpatient department with a fever, cough, and difficulty breathing for three days. During the exam, coarse crepitation is heard in his left lower chest. He's prescribed azithromycin 500mg once daily. Which parameter from a plasma concentration vs time graph best indicates the drug's absorption rate? (or) Which parameter would be best to explain the rate of drug absorption? A. Tmax B. Cmax C. Area under the curve D. Minimum effective concentration ---------------------------------------- 29. A 56-year-old patient with heart failure currently on digoxin therapy presents to the emergency department with blurred vision and yellow-green distortion. The plasma digoxin level is 4 ng/ml(normal 0.8- 2.0). Renal function is normal; this patient's plasma t1/2 for digoxin is 1.6 days. How long should digoxin be withheld to reach a safer yet probably therapeutic level of 1 ng/ml? (or) A heart failure patient on digoxin therapy presented with blurred vision and yellow-green distortion.. The plasma digoxin level is 4 ng/ml (normal 0.8- 2.0). Plasma t1/2 for digoxin in this patient is 1.6 days. How long should digoxin be withheld to reach a safer yet probably therapeutic level of 1 ng/ml? A. 1.6 days B. 2.4 days C. 3.2 days D. 4.8 days ---------------------------------------- 30. If 4g of antibiotic is administered and its peak plasma concentration is found to be 50 µg/ml, what will be the volume of distribution of the drug ? (or) If 4g of antibiotic is administered and its peak plasma concentration is found to be 50 µg/ml, what will be the drug's volume of distribution? A. 100 L B. 80 L C. 60 L D. 50 L ---------------------------------------- 31. A 51-year-old woman with hypertension & Type 2 DM has wrist pain, morning stiffness, and joint abnormalities. She has high RF titers and positive anticitrullinated protein antibodies. She's prescribed a renal tubule-secreted drug. Assuming renal clearance, what is the likely clearance of the drug? Page 9 9 (or) Tubular secretion of a drug can be assumed if renal clearance of drug X is? A. More than the GFR B. Less than the GFR C. Equal to the GFR D. Equal to the plasma concentration of the drug ---------------------------------------- 32. Which of the following statements best describes the pKa of a drug? (or) Which statements best describes the pKa of a drug? A. pKa of a drug is the pH at which the drug is 50% ionised B. Small changes in pH near the pKa of a weakly acidic drug will not affect its degree of ionisation C. Knowledge of the pKa of a drug is not necessary for predicting its behaviour in various body fluids D. Phenobarbitone (an acidic drug) with a pKa of 7.2 is largely unionised at alkaline pH ---------------------------------------- 33. A 38-year-old male patient arrives at the emergency department after consuming morphine for 6 hours. His respiratory rate is 12 breaths per minute, and he has bilateral pinpoint pupils. The plasma half-life of morphine is 3 hours, with a volume of distribution (Vd) of 200 L. The current plasma concentration of morphine is 0.5 mg/L. What is the initial dose of morphine consumed by the person? (or) What could be the initial morphine dose a person consumes while the current plasma concentration of morphine is 0.5mg/L with plasma half-life of morphine is 3 hours, and the volume of distribution (Vd) is 200 L? A. 100 mg B. 400 mg C. 10 mg D. 50 mg ---------------------------------------- 34. Certain drugs, such as chloroquine, require a high-loading dose followed by regular maintenance doses. Which of the following factors does this loading dose depend on? (or) A drug's loading dose depends upon which of the following factor? A. Drug concentration to be excreted B. Volume of distribution C. Clearance of the drug D. Maintenance dose ---------------------------------------- Page 10 10 35. Therapeutic monitoring of the plasma level of the drug is done when the drug's response cannot be measured. Which of the following drugs would not require therapeutic dose monitoring? (or) Which of the following drugs would not require therapeutic dose monitoring? A. Warfarin B. Gentamicin C. Cyclosporine D. Phenytoin ---------------------------------------- 36. Avoid which laxative in a 7-year-old child with constipation and a history of rheumatic fever on erythromycin prophylaxis due to the risk of arrhythmia? (or) Which of the following laxatives should be avoided in conjunction with erythromycin to prevent the development of any arrhythmia? A. Lubiprostone B. Streptomycin C. Ebastine D. Cisapride ---------------------------------------- 37. A 5 ml ampoule containing 5 mg/ml NTG. One ampoule is added to normal saline to make a total of 500 ml solution. Calculate the infusion rate if NTG is required at ten mcg/min. (Consider 1 micro drip = 60 drops/mL) (or) A 5 ml ampoule containing 5 mg/ml NTG. One ampoule is added to normal saline to make a total of 500 ml solution. Calculate the infusion rate if NTG is required at ten mcg/min. (Consider 1 micro drip = 60 drops/mL) A. 12 drops/min B. 14 drops/min C. 15 drops/min D. 16 drops/min ---------------------------------------- 38. Which of the following statements best describes drug distribution? (or) Which of the following statements best describes drug distribution? A. Plasma protein binding affects drug distribution B. The cell membrane allows more lipid-insoluble molecules to diffuse through it C. The degree of blood flow does not determine the distribution of a drug D. Pathological conditions do not alter the distribution of drug Page 11 11 ---------------------------------------- 39. A 57-year-old man is in the CCU post-treatment for ST-elevation myocardial infarction. Which of the following antiplatelet drugs might cause unexpected results based on the CYP2C19 genotype of the patient? (or) Which antiplatelet drug is affected by the CYP2C19 genotype? A. Prasugrel B. Clopidogrel C. Warfarin D. Omeprazole ---------------------------------------- Correct Answers Question Correct Answer Question 1 1 Question 2 3 Question 3 2 Question 4 4 Question 5 4 Question 6 3 Question 7 1 Question 8 2 Question 9 2 Question 10 2 Question 11 4 Question 12 4 Question 13 3 Question 14 4 Question 15 1 Question 16 1 Question 17 3 Question 18 3 Question 19 4 Question 20 4 Question 21 2 Question 22 1 Page 12 12 Question 23 1 Question 24 3 Question 25 1 Question 26 1 Question 27 4 Question 28 1 Question 29 3 Question 30 2 Question 31 1 Question 32 1 Question 33 2 Question 34 2 Question 35 1 Question 36 4 Question 37 1 Question 38 1 Question 39 2 Solution for Question 1: Correct Option A- Decreased glomerular filtration: This is a case of malarial prophylaxis in which a pregnant patient presents to the gynecologist for a prenatal visit. The patient wants to visit Mozambique in such areas, there is a high risk of coming in contact with a malarial parasite. Mefloquine is advised during pregnancy for prophylaxis against malarial parasites if at risk. High plasma protein binding leads to decreased glomerular filtration, as proteins being large in size and negatively charged, are not filtered through the glomerulus. Incorrect Options: Option B- High volume of distribution: Mefloquine has a low volume of distribution. High protein binding leads to a low volume of distribution into tissues as the protein-bound drug does not cross membranes. Option C- Shortened duration of action: Mefloquine has an increased duration of action. It is because the high protein binding of this drug leads to an increased duration of action, as only free drugs can be metabolized or excreted quickly. Option D- Decreased drug interaction: Page 13 13 Mefloquine's high protein binding can lead to increased drug interactions rather than decreased ones. Competition for protein binding sites with other drugs can potentially alter their pharmacokinetics and efficacy. Solution for Question 2: Correct Option C - Hepatic metabolism and renal excretion are the two most important mechanisms involved: Paracetamol is a commonly used over-the-counter antipyretic / non-opioid-analgesic medication for pain due to various etiologies. When given in the therapeutic dosage range, it undergoes hepatic metabolism into glucuronides & sulfates and later is excreted outside the body via the renal system. On overdose, there is noted hepatotoxicity due to the metabolite NAPQI. Paracetamol is a commonly used over-the-counter antipyretic / non-opioid-analgesic medication for pai n due to various etiologies. When given in the therapeutic dosage range, it undergoes hepatic metaboli sm into glucuronides & sulfates and later is excreted outside the body via the renal system. On overdo se, there is noted hepatotoxicity due to the metabolite NAPQI. Incorrect Options: Option A - Paracetamol must only be excreted from the body to terminate its action: Paracetamol has renal excretion. But its action is terminated after hepatic metabolism. So, it doesn't require excretion from the body for the termination of its action. Paracetamol has renal excretion. But its action is terminated after hepatic metabolism. So, it doesn't require excretion from the body for the termination of its action. Option B - Metabolism of drugs always abolishes their pharmacologic activity: Most of the drugs are inactivated by metabolism. However, some drugs may be activated from inactive form (prodrugs), and others may produce active metabolites. Most of the drugs are inactivated by metabolism. However, some drugs may be activated from inactive form (prodrugs), and others may produce active metabolites. Option D - Distribution of a drug out of the bloodstream terminates the drug’s effects: Some drugs may act away from blood, e.g. digoxin leaves the bloodstream and enters the heart to produce its action. Distribution is the process of a drug moving from the bloodstream to various tissues and organs in the body. However, termination of a drug's effects primarily occurs through metabolism and excretion, not simply by distribution out of the bloodstream. Therefore, this option is incorrect in the context of paracetamol's action termination. Some drugs may act away from blood, e.g. digoxin leaves the bloodstream and enters the heart to pro duce its action. Distribution is the process of a drug moving from the bloodstream to various tissues and organs in the body. However, termination of a drug's effects primarily occurs through metabolism and excretion, not simply by distribution out of the bloodstream. Therefore, this option is incorrect in the context of paracet Page 14 14 amol's action termination. Solution for Question 3: Correct Option B - Diclofenac sodium: This is a case of adhesive capsulitis. Diclofenac sodium is a weak acid and is non-ionized in the acidic medium of the stomach. The stomach's epithelial lining contains lipid-rich cell membranes. Lipid-soluble non-ionized molecules can readily diffuse across these membranes. This lipid solubility allows non-ionized drugs like diclofenac sodium to pass through the lipid bilayers of the epithelial cells, effectively crossing the stomach lining. Once absorbed through the stomach lining, diclofenac sodium enters the bloodstream. It can be distributed to its target tissues to exert pharmacological effects, such as reducing inflammation and relieving pain. Incorrect Options: Option A - Morphine sulfate: Morphine sulfate is a basic drug. Morphine sulfate is a narcotic analgesic commonly used for severe pain management. However, morphine is not well-absorbed from the stomach due to its poor water solubility and ionization characteristics. Its absorption primarily occurs in the small intestine rather than the stomach. Option C - Naproxen: Naproxen is another NSAID like diclofenac but is less likely to be absorbed from the stomach than diclofenac. While naproxen is well-absorbed from the small intestine, its absorption from the stomach is not as efficient as diclofenac's. Option D - Aspirin: Aspirin, also an NSAID, is rapidly absorbed from the stomach and upper small intestine. However, its absorption is influenced by factors such as food in the stomach and the formulation of the drug. While aspirin can be absorbed from the gastric mucosa, its absorption kinetics may not be as favorable as diclofenac. Solution for Question 4: Correct Option D - Inhalation route is the most appropriate choice for delivering bronchodilators to relie ve wheezing and shortness of breath: The inhalation route allows the medication to directly target the lungs, which is crucial for treating respiratory symptoms such as wheezing and shortness of breath. Bronchodilators delivered via inhalation act quickly and effectively to relax the airway muscles and improve airflow, providing prompt relief of symptoms. Page 15 15 The inhalation route is highly suitable for delivering bronchodilators: Direct Delivery: Medication goes straight to the lungs, targeting the airways and bronchioles. Rapid Onset: Provides quick relief, often within minutes. Lower Systemic Side Effects: Minimizes absorption into the bloodstream, reducing systemic side effects. Enhanced Efficacy: Ensures a higher concentration of medication reaches the lungs, improving effectiveness. Direct Delivery: Medication goes straight to the lungs, targeting the airways and bronchioles. Rapid Onset: Provides quick relief, often within minutes. Lower Systemic Side Effects: Minimizes absorption into the bloodstream, reducing systemic side effects. Enhanced Efficacy: Ensures a higher concentration of medication reaches the lungs, improving effectiveness. Direct Delivery: Medication goes straight to the lungs, targeting the airways and bronchioles. Rapid Onset: Provides quick relief, often within minutes. Lower Systemic Side Effects: Minimizes absorption into the bloodstream, reducing systemic side effects. Enhanced Efficacy: Ensures a higher concentration of medication reaches the lungs, improving effectiveness. Incorrect Options: Option A - Intravenous route should be avoided due to the risk of exacerbating wheezing symptoms: Intravenous administration is used in the treatment of asthma attacks with drugs like steroids, magnesium sulfate, etc. Option B - The subcutaneous route is preferred for immediate relief of symptoms due to its rapid onset of action: Subcutaneous administration is not used for bronchodilators as it will not provide the rapid onset of action required for relieving acute respiratory symptoms. The inhalation route offers a more direct and effective means of delivering medication to the lungs. Option C - The oral route is contraindicated as it may worsen the patient's symptoms of sneezing and coughing: Oral route is not preferred due to its slow action of onset. In an acute setting, inhalational or IV treatment should be used. Oral administration per say does not increase symptoms. It can be used for maintenance therapy. Solution for Question 5: Correct Option D - Clearance of the drug: The maintenance dose rate of a drug can be calculated using the formula: Maintenance dose rate = (Clearance × Target plasma concentration) / Fraction of dose entering the systemic circulation. Maintenance dose rate = (Clearance × Target plasma concentration) / Fraction of dose entering the systemic circulation. A drug's maintenance dose rate primarily depends on its clearance, which represents the rate at which the drug is eliminated from the body. Clearance is a crucial pharmacokinetic parameter that Page 16 16 determines the dosing regimen needed to maintain therapeutic drug levels in the body over time. Drugs with higher clearance require a higher maintenance dose rate to compensate for their rapid elimination and maintain effective drug concentrations. The maintenance dose rate of a drug can be calculated using the formula: Maintenance dose rate = (Clearance × Target plasma concentration) / Fraction of dose entering the systemic circulation. Maintenance dose rate = (Clearance × Target plasma concentration) / Fraction of dose entering the systemic circulation. A drug's maintenance dose rate primarily depends on its clearance, which represents the rate at which the drug is eliminated from the body. Clearance is a crucial pharmacokinetic parameter that determines the dosing regimen needed to maintain therapeutic drug levels in the body over time. Drugs with highe r clearance require a higher maintenance dose rate to compensate for their rapid elimination and maint ain effective drug concentrations. Incorrect Options: Option A - Volume of distribution: The volume of distribution (Vd) reflects the extent of a drug's distribut ion throughout the body relative to its plasma concentration. While Vd influences the initial distribution of a drug, it does not directly dictate the maintenance dose rate. Clearance, not volume of distribution, governs the rate at which the drug is eliminated from the body and thus determines the maintenance d osing. Option B - Protein binding affinity of the drug: Protein binding affinity affects the distribution and availability of a d rug in the body but does not directly influence the maintenance dose rate. Protein-bound drugs may ha ve a longer duration of action due to slower release from protein binding sites, but their maintenance d osing is primarily determined by factors such as clearance and half-life. Option C - Lipid solubility: Lipid solubility influences a drug's distribution and ability to penetrate cell me mbranes but is not directly related to the maintenance dose rate. While lipid-soluble drugs may have e nhanced tissue penetration and longer duration of action, their maintenance dosing is determined by fa ctors such as clearance and therapeutic goals, rather than lipid solubility alone. Solution for Question 6: Correct Option C - Phenobarbital: This is a case of phenobarbital poisoning in which the patient presents in an altered state of consciousness. The patient is not able to walk straight has slurred speech and has hypotension. Phenobarbital - is a derivative of barbituric acid (weakly acidic drug), and its excretion can be enhanced by making the urine alkaline. As well as use of multidose-activated charcoal. Absorption and reabsorption of a drug depend on its lipid solubility. When a drug is in a similar medium (acidic drug in an acidic medium or a basic drug in a basic medium), it easily crosses the membrane in its non-ionized form and gets absorbed/ reabsorbed. Thus, in some acidic drug poisoning (salicylate, barbiturates, etc.), urine can be alkalinized with sodium bicarbonate because weak acids are in ionized form in alkaline urine and thus are easily excreted. Incorrect Options: Page 17 17 Option A - Morphine: Morphine is a basic drug. So, in this type of poisoning, urine should be acidified using ammonium chloride. In the above-mentioned case, urine was alkalinized, so morphine is unlikely responsible for the patient’s condition. Option B - Amphetamine: Amphetamine is a basic drug. In the cases of basic drug poisoning, ammonium chloride should be used to acidify urine. Option D - Atropine: Atropine poisoning can cause symptoms such as tachycardia, dry mouth, blurred vision, and delirium. Alkaline diuresis is not indicated for atropine poisoning because atropine is a tertiary amine and is well absorbed and metabolized in the body Solution for Question 7: Correct Option A - Marked redistribution due to high lipid solubility: Highly lipid-soluble drugs initially reach organs with high blood flow, such as the brain, heart, and kidneys. Later, less vascular but bulkier tissues like muscle and fat start taking the drug. As plasma concentration decreases, the drug is pulled back from highly perfused sites. If the drug's action site is in a highly perfused organ, this redistribution ends the drug's effect. For instance, thiopentone's IV injection leads to its anesthesia effect ending in minutes due to redistribution. The higher the lipid solubility of the drug, the quicker its redistribution happens. Highly lipid-soluble drugs initially reach organs with high blood flow, such as the brain, heart, and kidne ys. Later, less vascular but bulkier tissues like muscle and fat start taking the drug. As plasma concentration decreases, the drug is pulled back from highly perfused sites. If the drug's action site is in a highly perfused organ, this redistribution ends the drug's effect. For insta nce, thiopentone's IV injection leads to its anesthesia effect ending in minutes due to redistribution. The higher the lipid solubility of the drug, the quicker its redistribution happens. Incorrect Options: Option B- Marked redistribution as it contains weak electrolytes: Thiopentone doesn’t have weak electrolytes. Its action subsides within 15 minutes because it is redistributed to fewer vascular organs after 15 minutes. Thiopentone doesn’t have weak electrolytes. Its action subsides within 15 minutes because it is redistri buted to fewer vascular organs after 15 minutes. Option C- Marked redistribution due to high plasma protein binding: Page 18 18 The high plasma protein binding usually results in an increased duration of action. However, thiopentone has a short duration of CNS effect. The high plasma protein binding usually results in an increased duration of action. However, thiopenton e has a short duration of CNS effect. Option D- Marked redistribution due to high water solubility: It is highly lipid soluble, which carries it to high blood flow organs at first. After 15 minutes, its plasma concentration decreases, which results in its redistribution to less vascular organs. It is highly lipid soluble, which carries it to high blood flow organs at first. After 15 minutes, its plasma concentration decreases, which results in its redistribution to less vascular organs. Solution for Question 8: Correct Option B - It is excreted faster in acidic urine: This is a case of nephrolithiasis in which the patient presents with complaints of severe right-sided flank pain for 1 hour. The ultrasound of the patient revealed multiple right-sided renal calculi. Tramadol is a weakly basic drug. Weakly basic drugs dissolve more easily in acidic urine and are excreted faster. The weakly basic drugs include: Telmisartan Tramadol Nalbuphine Morphine Olanzapine Sildenafil citrate Telmisartan Tramadol Nalbuphine Morphine Olanzapine Sildenafil citrate Telmisartan Tramadol Nalbuphine Morphine Olanzapine Sildenafil citrate Incorrect Options: Option A - It is bound primarily to plasma albumin: Basic drugs bind to alpha-1 glycoprotein. Acidic drugs are bound primarily to plasma albumin. Page 19 19 Option C - It is highly ionized in the intestinal secretions: Basic drugs are ionized in the stomach. While acidic drugs are highly ionized in the intestinal juice. Option D - It is absorbed mainly from the stomach: Basic drugs are best absorbed in the intestine. Meanwhile, acidic drugs are absorbed mainly from the stomach. Solution for Question 9: Correct Option B - Most common phase II drug metabolising reaction is glucuronidation: The most common phase II drug metabolizing reaction is glucuronidation. The microsomal enzyme glucuronyl transferase catalyzes it. During phase I reaction, a drug is transformed into a polar, water-soluble metabolite by cytochrome P450 oxidation, reduction, and hydrolysis reactions. During phase II reaction, a drug is conjugated and transformed into a very polar metabolite that can be excreted via kidneys by glucuronidation, acetylation, and sulfation methylation reactions. In older people, phase I reactions usually become impaired before phase II reactions. Oxidation, reduction, hydrolysis, cyclisation and decyclization etc. Glucuronidation, acetylation, methylation, sulfation, glycine conjugation, etc. Incorrect Options: Option A - At the end of phase I, all the drugs become water-soluble: At the end of phase I, the drug may either become water soluble or lipid soluble. After phase II reactions, the drug ultimately becomes water-soluble. Option C - Function of phase I reactions is to attach a conjugate to the drug molecule: The function of phase I reactions is to attach a functional group to the drug molecule. The function of phase II reactions is to attach a conjugate to the drug molecule. Option D - At the end of phase II, all the drugs become lipid-soluble: After phase II reactions, the drug ultimately becomes water-soluble. Phase II reactions include glucuronidation, acetylation, methylation, sulfation, and glycine conjugation. At the end of phase I, the drug may either become water soluble or lipid soluble. Solution for Question 10: Correct Option B - Enalapril: This is a case of hypertension. Page 20 20 The doctor prescribed enalapril in this case. It exerts its action for 24 hours. Prodrugs are drugs that are converted to active metabolites within the body Enalapril is an ACE inhibitor and is a prodrug, which gets converted to its active metabolite enalaprilat through ‘de-esterification’ in the liver. Important examples of prodrugs include: Prefer Prednisone Proton pump inhibitors Proguanil M Mercaptopurine Methyldopa Clinical Cyclophosphamide Clopidogrel Incorrect Options: Option A - Metoprolol: Metoprolol is a cardioselective Beta-blocker with intrinsic sympathomimetic activity and is not a prodrug. It is used in the treatment of hypertension, angina and hyperthyroidism. Metoprolol is metabolised in the liver via the cytochrome P450. Option C - Telmisartan: Telmisartan is angiotensin-II receptor antagonist (ARB). It is used to treat hypertension. Telmisartan is not a prodrug. Losartan which is another ARB is however a prodrug. Option D - Amlodipine: Amlodipine is a calcium channel blocker. It lowers high blood pressure, relaxes heart muscles and dilates blood vessels to prevent spasms. It is also not a prodrug. Solution for Question 11: Correct Option D - The rate of elimination is proportional to plasma concentration: The corticosteroids follow first-order kinetics. In this kinetics, the rate of elimination is proportional to the plasma concentration. Page 21 21 In zero-order kinetics, the rate of metabolism remains constant and is independent of the plasma concentration of a drug at a steady state. In first-order kinetics, the rate of metabolism is directly proportional to the plasma concentration of the drug. Incorrect Options: Option A - Half-life is less at low concentrations and more at high concentrations: In first-order kinetics, half-life remains constant. In zero-order kinetics, the half-life is less at low concentrations and more at high concentrations. The formula for calculating the half-life (t1/2) in first-order kinetics is: t1/2 = 0.693 / k Option B - Most drugs follow zero-order kinetics: Most of the drugs follow first-order kinetics. There are very few drugs that follow zero-order kinetics, such as aspirin, warfarin, theophylline, phenytoin and tolbutamide. Option C - Clearance is less at low concentrations: In first-order kinetics, clearance remains constant. In zero-order kinetics, clearance is more at low and less at high concentrations. Clearance is the volume of plasma cleared of a drug over a specified time period. It is not to be confused with elimination which proportionately increases/decreases with a change in drug concentration in first order kinetics Solution for Question 12: Correct Option D - Rifampicin: This is a case of leprosy in which the patient presents with complaints of paresthesias in his feet and a hypopigmented skin lesion on his knee for seven weeks. He also gives a history of fever, fatigue, and malaise for one week. The drug involved in this case is rifampicin. It is an enzyme inducer. It is used in the treatment of leprosy. It is also a mainstay in the treatment of tuberculosis. Rifampicin induces the following cytochrome enzymes: CYP3A4 CYP1A2 CYP2C9 CYP2C19 CYP3A4 CYP1A2 CYP2C9 CYP2C19 Cytochrome Enzyme Inducers CYP3A4 CYP1A2 Page 22 22 CYP2C9 CYP2C19 G Griseofulvin P Phenytoin R Rifampicin S Smoking Cell Carbamazepine Phone Phenobarbitone Incorrect Options: Option A - Ciprofloxacin: Ciprofloxacin is an enzyme inhibitor. It is commonly used in the treatment of abdominal infections such as infectious diarrhoea and typhoid. This drug will not result in the induction of enzymes. Option B - Isoniazid: Isoniazid is an enzyme inhibitor. It is a mainstay in the treatment of tuberculosis. It doesn’t result in the induction of enzymes. Option C - Ketoconazole: Ketoconazole is an enzyme inhibitor. It is usually used in the treatment of fungal skin infections and seborrheic dermatitis. It has no role in leprosy and is not an enzyme inducer Solution for Question 13: Correct Option C - Clearance decreases with an increase in plasma concentration: Aspirin is a drug that follows zero-order kinetics at higher doses. In zero-order kinetics, clearance is inversely proportional to the plasma concentration. Incorrect Options: Option A - Half-life is constant: The half-life is not constant in zero-order kinetics Page 23 23 The length of half-life is constant in first-order kinetics Half-life increases at high concentrations due to a fixed amount of drug being eliminated. Option B - The rate of elimination is dependent on plasma drug concentration: The rate of elimination of zero-order kinetic drugs doesn’t depend on the plasma concentration of a drug Option D - Majority of the drugs have similar characteristics: Very few drugs follow pure zero-order kinetics. It includes: Warfarin Theophylline Tolbutamide Phenytoin Warfarin Theophylline Tolbutamide Phenytoin Warfarin Theophylline Tolbutamide Phenytoin Solution for Question 14: Correct Option D - The drug is not extensively distributed to tissues: The volume of distribution (Vd) signifies the distribution of a drug in the tissues. Drugs that are lipid soluble are more likely to cross the blood vessel wall and thus have a high volume of distribution. If a drug is highly bound to plasma proteins, it is likelier to stay in the plasma. Therefore, less will go to tissues resulting in a reduced volume of distribution. Incorrect Options: Option A - The drug has a longer half-life: The half-life of a drug depends upon its metabolism and excretion from the body. Half-life (hours) = 0.693 × (Volume of distribution (L) / Clearance (L/hr)) The longer it takes for its metabolism, the longer it will stay in circulation. Thus, the half-life will be longer. Option B - The drug has low bioavailability: Bioavailability is the amount of drug that reaches the systemic circulation. The bioavailability is determined by the route of transmission of a drug. It is not determined by the volume of distribution. Option C - The drug has low efficacy: The efficacy is the magnitude of the drug’s response when it interacts with a receptor. Page 24 24 The efficacy of a drug depends upon its ability to activate the receptor and cause a cellular response, not on its volume of distribution. Solution for Question 15: Correct Option A - Intravenous: The intravenous route is the route that can ensure 100% bioavailability of a drug. Bioavailability is the fraction of administered drugs that reaches the systemic circulation in the unchanged form. Incorrect Options: Option B - Oral route: While the oral route is convenient and commonly used, it is subject to variability i n absorption due to factors such as gastric emptying time, gastrointestinal pH, and first-pass metabolis m in the liver. As a result, bioavailability can vary among individuals and medications. Achieving 100% bioavailability via the oral route is rare, as some portion of the medication may be lost during absorptio n or metabolism. Option C - Intramuscular route: The intramuscular route involves administering the medication into mus cle tissue, which is absorbed into the bloodstream. While this route can provide relatively rapid absorpti on and avoid issues with gastrointestinal absorption, it does not ensure 100% bioavailability. Factors s uch as the injection site, blood flow to the muscle, and medication characteristics can affect absorption rates and bioavailability. Option D - Sublingual route: Sublingual administration involves placing the medication under the tongu e, which is absorbed directly into the bloodstream through the highly vascularized sublingual mucosa. While this route can result in a rapid onset of action and avoid first-pass metabolism, achieving 100% b ioavailability may not be guaranteed for all medications. Variability in absorption and potential medicati on loss through saliva swallowing can affect bioavailability. Solution for Question 16: Correct Option A - Oral: Nitrates, such as nitroglycerin, undergo extensive first-pass metabolism when administered orally. After oral ingestion, nitrates are absorbed from the gastrointestinal tract and undergo significant metabolism in the liver before reaching systemic circulation. This hepatic first-pass metabolism reduces the bioavailability of orally administered nitrates, resulting in lower plasma concentrations and decreased efficacy compared to other routes of administration. Drugs with High First pass Metabolism Incorrect Options: Option B - Intravenous: The drugs administered via IV infusion don't undergo first-pass metabolism. So, via this route, there is no first-pass metabolism and 100% bioavailability. Option C - Sublingual: Page 25 25 Nitrates are most commonly administered sub-lingually because 90% of nitroglycerin is cleared through the first-pass metabolism, if taken orally. The sublingual route bypasses the liver, reducing the first-pass effect, as drugs absorbed under the tongue enter directly into the bloodstream. Option D - Subcutaneous: The subcutaneous method has a moderate first-pass metabolism. Solution for Question 17: Correct Option C - The area under the curve tells the extent of absorption: The graph shown in the image above is a graded dose-response curve. The area under the curve (AUC) is bioavailability. It tells us about the extent of absorption. Incorrect Options: Option A - Tmax of the drug is 3 hours: Tmax is the time required to attain Cmax (Maximum Concentration). It is 2 hours in the graph involved in this case. It describes about the rate of absorption. Option B - The Cmax of the drug in this graph is 100 mg/dl: Cmax is the maximum concentration obtained with a particular dose. It is 120 mg/dL in the given graph Option D - The graph can be used to calculate ED50: The graph involved in this case is a graded dose-response curve. ED50 and LD50 are calculated from the quantal dose-response curve. Page 26 26 Solution for Question 18: Correct Option C - Dose of the drug: The dose of the drug is usually affected by bioavailability. Bioavailability Fraction of dose reaching the systemic circulation. Important in determining the dose required to establish therapeutic effects High bioavailability → lower dose Low bioavailability → higher dose Fraction of dose reaching the systemic circulation. Important in determining the dose required to establish therapeutic effects High bioavailability → lower dose Low bioavailability → higher dose Factors affecting bioavailability Absorption More absorption, more bioavailability First-pass metabolism More first-pass metabolism, less bioavailability Absorption More absorption, more bioavailability More absorption, more bioavailability First-pass metabolism More first-pass metabolism, less bioavailability More first-pass metabolism, less bioavailability Fraction of dose reaching the systemic circulation. Important in determining the dose required to establish therapeutic effects High bioavailability → lower dose Low bioavailability → higher dose Absorption More absorption, more bioavailability More absorption, more bioavailability First-pass metabolism More first-pass metabolism, less bioavailability More first-pass metabolism, less bioavailability More absorption, more bioavailability More first-pass metabolism, less bioavailability Incorrect Options: Option A - Half-life of the drug: The half-life of a drug depends upon its metabolism and excretion from the body. It doesn't depend upon the bioavailability of the drug. Option B - Volume of distribution: Bioavailability is the rate at which a drug reaches systemic circulation. The bioavailability is determined by the route of transmission of a drug. It is not affected by the volume of distribution. Option D - pKa value: Page 27 27 pKa is the pH of the medium at which 50% of the drug can cross the membrane and 50% cannot cross the membrane. It has no role in bioavailability. Solution for Question 19: Option D: TDM can be done if the drug has erratic pharmacokinetics TDM is done if a drug has inconsistent pharmacokinetics. Therapeutic dose monitoring is done only for drugs (with a narrow therapeutic index) whose response cannot be monitored by simple laboratory parameters and have inconsistent/ erratic pharmacodynamics. An antihypertensive's effects can easily be measured via blood pressure monitoring and hence does not require TDM Option A: Done when the clinical response can be easily measured It is not done for drugs whose clinical response can be measured easily, such as antihypertensive drugs. It is done when the therapeutic response cannot be easily measured. Option B: Done for wide therapeutic index drugs TDM is not done for drugs having a wide therapeutic index. It is done for drugs having low therapeutic indexes, such as digoxin and phenytoin. Option C: Atenolol is an example of a drug for which TDM is done TDM is not done for atenolol. TDM is done for the drugs mentioned in the following table: Solution for Question 20: Correct Option D - BCG: BCG vaccine is used for the prevention of tuberculosis. It is given by intradermal route, where the drug is injected into the skin, raising a bleb. Examples of drugs administered through this route are: Rabies vaccine BCG Rabies vaccine BCG BCG vaccine is used for the prevention of tuberculosis. It is given by intradermal route, where the drug is injected into the skin, raising a bleb. Examples of drugs administered through this route are: Rabies vaccine Page 28 28 BCG Rabies vaccine BCG Incorrect Options: Option A- Filgrastim: Filgrastim is a drug which is used to treat low neutrophil count. It is given by subcutaneous route. Filgrastim is a drug which is used to treat low neutrophil count. It is given by subcutaneous route. Option B- Insulin: Insulin is commonly used for the treatment of diabetic patients. It can be given subcutaneously or intravenously. Insulin is commonly used for the treatment of diabetic patients. It can be given subcutaneously or intravenously. Option C- Tetanus toxoid: Tetanus toxoid is given intramuscularly. Tetanus toxoid is given intramuscularly. Solution for Question 21: Correct Option B - Terminal half-life: Gentamicin is an antibiotic with bactericidal activity against gram-negative bacteria. With prolonged dosing, a drug may penetrate beyond the central compartment into secondary body compartments that slowly equilibrate with the plasma. While the drug is clearing from the plasma, it will eventually drop to a point at which net diffusion from the secondary compartments begins, and this slow pseudo-equilibration will produce a prolongation of the half-life, referred to as the terminal half-life. Terminal half-life is the time required for a drug to reach half its concentration after reaching pseudo-equilibrium. Incorrect Options: Option A - Secondary half-life: Secondary half-life is not a term used in pharmacology. Option C - Zero-order half-life: Zero order Kinetics is when the drug concentration decreases linearly. Option D - First-order half-life: Half life is the time needed to reach half of the concentration of the drug. Page 29 29 First-order half-life is not a term that used in pharmacology Solution for Question 22: Correct Option A- Propranolol: Propranolol is a beta blocker frequently used to lower blood pressure. Cytochrome P450 enzymes are expressed mainly in the endoplasmic reticulum of hepatocytes. CYP2D6 enzyme accounts for the clearance of about 20-25% of all drugs. Drugs that act as substrates for the CYP2D6 enzyme are beta blockers, antidepressants, antiarrhythmic drugs, antipsychotics and codeine. CYP 3A4 substrate CYP 2D6 substrate CYP2C19 CYP2C9 Incorrect Options: Option B- Warfarin: The CYP2C9 enzyme metabolizes warfarin in the liver. It is used in the treatment of deep vein thrombosis and pulmonary embolism. Option C- Atorvastatin: Atorvastatin is a CYP3A4 substrate. Atorvastatin is commonly used in the treatment of hyperlipidemia. Option D- Clopidogrel: It is a CYP2C19 substrate. It is an antiplatelet drug. Solution for Question 23: Correct Option A- Hydroxylation: Hydroxylation belongs to phase 1 reactions. Phase 1 reactions These are non-synthetic reactions. The phase 1 enzymes introduce functional groups, such as –OH, –COOH, –SH, –O–, or NH2, to the drug. The enzymes include - Cytochrome P450s, Flavin-containing monooxygenases (FMOs), and Epoxide hydrolases (EHs). This alters the biological properties of the drug. It includes oxidation, reduction, and hydrolytic reactions. These are non-synthetic reactions. The phase 1 enzymes introduce functional groups, such as –OH, –COOH, –SH, –O–, or NH2, to the drug. Page 30 30 The enzymes include - Cytochrome P450s, Flavin-containing monooxygenases (FMOs), and Epoxide hydrolases (EHs). This alters the biological properties of the drug. It includes oxidation, reduction, and hydrolytic reactions. Phase 2 reactions These are synthetic reactions. Phase 2 reactions include conjugation of the products of the phase 1 reactions. They improve the water solubility of the drug and increase its elimination. It includes Glucuronidation (Most common) Acetylation Methylation Sulfation Glycine conjugation These are synthetic reactions. Phase 2 reactions include conjugation of the products of the phase 1 reactions. They improve the water solubility of the drug and increase its elimination. It includes Glucuronidation (Most common) Acetylation Methylation Sulfation Glycine conjugation Glucuronidation (Most common) Acetylation Methylation Sulfation Glycine conjugation These are non-synthetic reactions. The phase 1 enzymes introduce functional groups, such as –OH, –COOH, –SH, –O–, or NH2, to the drug. The enzymes include - Cytochrome P450s, Flavin-containing monooxygenases (FMOs), and Epoxide hydrolases (EHs). This alters the biological properties of the drug. It includes oxidation, reduction, and hydrolytic reactions. These are synthetic reactions. Phase 2 reactions include conjugation of the products of the phase 1 reactions. They improve the water solubility of the drug and increase its elimination. It includes Glucuronidation (Most common) Acetylation Methylation Sulfation Glycine conjugation Glucuronidation (Most common) Acetylation Methylation Sulfation Glycine conjugation Glucuronidation (Most common) Acetylation Methylation Sulfation Page 31 31 Glycine conjugation Incorrect Options: Option B- Methylation: Methylation is a phase 2 reaction. It involves the conjugation of the drug substrate with a methyl group to increase its solubility in water. Option C- Conjugation: Conjugation is an example of phase 2 reactions. Option D- Acetylation: Acetylation is a type of phase 2 reaction involving a drug substrate's ethanoylation. Sulfamethoxazole is an example of a drug that undergoes this reaction. Solution for Question 24: Correct Option C - Amphetamine: In this case, the patient presented in a semi-conscious state with tachypnea and vomiting due to drug overdose toxicity. Most drugs are metabolized in the liver and excreted by the kidneys. During the poisoning of drugs, multiple mechanisms work to remove the drug from the body. Changes in urinary pH affect tubular reabsorption of partially ionized drugs. Weak bases ionize more and are less reabsorbed in acidic urine. Weak acids ionize more and are less reabsorbed in alkaline urine. Urine is acidified in case of amphetamine poisoning, as amphetamine is basic. It ionizes more and reabsorbs less in acidic urine. Incorrect Options: Option A- Salicylates: Urinary pH has a great impact on the reabsorption of a drug. Weak acids ionize more and reabsorb less in alkaline urine. Urine is alkalinized in salicylate poisoning, as salicylate is a weak acid, so it ionizes more and reabsorbs less in alkaline urine. Option B- Barbiturates: Urinary pH has a great impact on the reabsorption of a drug. Weak acids ionize more and reabsorb less in alkaline urine Urine is alkalinized in barbiturate poisoning, as it is a weak acid, so it ionizes more and reabsorbs less in alkaline urine. Option D - Methotrexate: Urinary pH has a great impact on the reabsorption of a drug. Weak acids ionize more and reabsorb less in alkaline urine Page 32 32 Urine is alkalinized in methotrexate poisoning, as it is a weak acid, so it ionizes more and reabsorbs less in alkaline urine. Solution for Question 25: Correct Option A- Drug A does not maintain persistent therapeutic levels when administered every 24 hours: From the graph, Drug, A does not maintain persistent therapeutic levels when administered every 24 hours. The drug concentration reaches zero by the time the next dose is administered. Drug A is non-cumulative when administered every 24 hours because its concentration is never more than first-day peak levels Incorrect Options: Option B- Drug A exhibits cumulative properties: Drug B exhibits cumulative properties, not A and its concentration constantly increases with every dose. Drug A concentration decreases to zero every 24 hours. Option C- Drug B is non-cumulative when administered every 24 hours: Drug A is non-cumulative when administered every 24 hours because its concentration is never more than the first day's peak levels. Drug B exhibits cumulative properties, not A and its concentration constantly increases with every dose. Option D- Drug B is destroyed in less than 24 hours: Drug B is not destroyed in less than 24 hours and shows cumulative properties. Drug A is destroyed in less than 24 hours and its concentration reaches zero by the time the next dose is administered. Solution for Question 26: Correct Option A- They avoid the hepatic first-pass metabolism of the drug: In this case, a patient has been given a transdermal patch of fentanyl for postoperative pain relief a few days after surgery. The transdermal route is employed for highly lipid-soluble drugs that can traverse intact skin. The size of the pores in the transdermal patch is adjusted to produce a uniform and smooth absorption of the drug. They minimize inter-individual variations in the achieved plasma drug concentration. As the drug is going directly into the bloodstream, first-pass hepatic metabolism is avoided. For example, in transdermal patches, Rotigotine is used for Parkinson's disease, and Fentanyl is used for postoperative pain relief. Page 33 33 Incorrect Options: Option B- They produce a high peak plasma concentration of the drug: The transdermal route is employed for lipophilic drugs. The size of the pores in the transdermal patch is adjusted to produce a uniform and smooth absorption of the drug. This will, thus, produce a delayed and smaller peak in the plasma concentration. Option C- They produce fluctuating plasma concentrations of the drug: The size of the pores in the transdermal patch is adjusted to produce a uniform and smooth absorption of the drug. They produce smooth and non-fluctuating plasma concentrations of the drug. Option D- The transdermal route is employed for water-soluble drugs: The transdermal route is employed for highly lipid-soluble drugs that can traverse intact skin. Solution for Question 27: Correct Option D- Chloroquine: The extent of distribution of a drug depends on its; lipid solubility, ionization at physiological pH, the extent of binding to plasma proteins, presence of tissue-specific transporters, and difference in regional blood flow. Chloroquine is highly lipid soluble, with a greater affinity to bind with plasma proteins. Chloroquine has the highest volume of distribution. It is concentrated in the liver and retina and excreted through the liver and kidneys. Incorrect Options: Option A- Haloperidol: Haloperidol is an antipsychotic drug. It is lipid soluble, with a great affinity to bind with plasma protein, resulting in a high volume of distribution. Haloperidol has less volume of distribution as compared to chloroquine. Option B- Gentamicin: Gentamicin is an antimicrobial drug. It is a lipid insoluble drug and because of its polar nature, it cannot cross many membranes. Thus, it has a low volume of distribution. Option C- Heparin: Heparin is an anticoagulant drug. It has a high molecular weight compound, not able to cross most of the membranes. It has a low volume of distribution. It is given in the prophylaxis of venous thromboembolism. Page 34 34 Solution for Question 28: Correct Option A- Tmax: Tmax is the time a drug takes to reach maximum concentration in plasma after oral administration. At Tmax, the rate of absorption is equal to the rate of elimination of the drug. It is a rough marker for an average rate of drug absorption. Incorrect Options: Option B: Cmax: Cmax is the maximum plasma concentration of a drug that can be obtained after giving a particular dose. It depends on the dose administered, the rate constant for absorption and the elimination constant of the drug. Option C- Area under the curve: The area under the curve tells us the extent to which an administered drug reaches the systemic circulation, i.e., the total amount of drug absorbed. Option D- Minimum effective concentration: It represents the minimum concentration of the drug needed to saturate the receptors and produce the required pharmacological effect. Solution for Question 29: Correct Option C- 3.2 days: The patient has digitalis toxicity as the digoxin serum levels are above the therapeutic range, and he's experiencing visual disturbances. Digoxin elimination follows first-order kinetics, i.e., a constant fraction of drugs is eliminated per unit of time, and the half-life remains constant. Page 35 35 The time required to decrease the plasma concentration of digoxin from 4 ng/ml to 1 ng/ml will take approximately two half-lives (From 4 ng/ml to 2 ng/ml in one half-life and from 2 ng/ml to 1 ng/ml in second half-life). Thus, the time required will be two × t½, i.e., two × 1.6 = 3.2 days. Half-life is the time required to change the drug in the body by half during elimination. For drugs following first-order kinetics, the clearance and plasma half-life remain constant. In such drugs, nearly complete drug elimination occurs in 4-5 half-lives. The patient has digitalis toxicity as the digoxin serum levels are above the therapeutic range, and he's experiencing visual disturbances. Digoxin elimination follows first-order kinetics, i.e., a constant fraction of drugs is eliminated per unit of time, and the half-life remains constant. The time required to decrease the plasma concentration of digoxin from 4 ng/ml to 1 ng/ml will take approximately two half-lives (From 4 ng/ml to 2 ng/ml in one half-life and from 2 ng/ml to 1 ng/ml in second half-life). Thus, the time required will be two × t½, i.e., two × 1.6 = 3.2 days. Half-life is the time required to change the drug in the body by half during elimination. For drugs followi ng first-order kinetics, the clearance and plasma half-life remain constant. In such drugs, nearly complete drug elimination occurs in 4-5 half-lives. Incorrect Options: Option A- 1.6 days: This option represents the one-half-life of digoxin, during which the drug concentrat ion would decrease by half. However, reaching a safer yet probably therapeutic level of 1 ng/ml from an initial level of 4 ng/ml would require more than one half-life. Option B- 2.4 days: This option represents one and a half times the duration of one half-life of digoxin. While it would significantly reduce digoxin concentration, it may not be sufficient to reach the target lev el of 1 ng/ml. Option D- 4.8 days: This option represents three times the duration of one half-life of digoxin. While it li kely results in a substantial reduction in digoxin concentration, reaching the target level of 1 ng/ml may take longer than necessary. Solution for Question 30: Correct Option B- 80L: To calculate the volume of distribution Vd, the following formula is used: Vd = amount of drug given (mg)/ plasma drug concentration (mg/L). Amount of drug in the body = 4g = 4000mg Plasma concentration = 50µg/ml = 50mg/L Vd= (4000mg)/(50mg/l)= 80L The volume of distribution is the fluid volume required to contain the entire drug in the body at the same concentration as measured in plasma. Factors determining Vd include fat: lean body mass ratio, PKA value of the drug, degree of plasma protein binding, and the affinity of the drug for different tissues and diseases, e.g., uraemia, heart failure etc. Page 36 36 Solution for Question 31: Correct Option A- More than the GFR: The patient has rheumatoid arthritis for which the doctor prescribed methotrexate. Methotrexate is cleared from the body via glomerular filtration and active tubular secretion, which makes the clearance greater than the GFR. Glomerular filtration rate (GFR) is the rate at which fluid is filtered through the glomeruli of the kidneys. It represents the total filtration rate by all functioning nephrons in the kidneys. Renal clearance includes not only substances that are filtered through the glomeruli but also those that are actively secreted or reabsorbed by the renal tubules. For a drug that is actively secreted by the renal tubules, its renal clearance will be greater than the GFR because it undergoes additional elimination beyond filtration. Incorrect Options: Option B- Less than the GFR: Substances that are not freely filtered or reabsorbed after glomerular filtration in the tubules have a clearance less than the GFR. For example: Cimetidine Option C- Equal to the GFR: If the substance is freely filtered and not reabsorbed along the tubules, and no additional substance is added via tubular secretion, then the renal clearance will be equal to the GFR (125ml/min), e.g., inulin. Option D- Equal to the plasma concentration of the drug: Plasma concentration is a part of the formula to calculate clearance. Clearance (CL) = Rate of elimination/ plasma concentration. Clearance can not be equal to the plasma concentration. These two parameters are not comparable in terms of their units (volume per unit time vs mass per unit volume) Solution for Question 32: Correct Option A- The pKa of a drug is the pH at which the drug is 50% ionized: pKa is the pH of the medium at which the drug is 50% ionized and 50% non-ionized. Most drugs are weak acids or weak bases. They exist in the solution in either ionized or non-ionized form. The ionized form of a weak acid is neutral, hydrophilic, and non-lipid-soluble; hence it can not penetrate the cell membrane. Non-ionized forms of molecules are more lipid-soluble and cross through the cell membrane more easily. Page 37 37 The pKa of the drug is the pH of the solution at which the drug is 50% in ionized form and 50% non-ionized form. When the medium is of the exact nature of the drug, the drug crosses lipid membranes, i.e. acidic drug crosses in acidic medium, whereas basic drug crosses in basic medium. The Handerson-Hasselbalch equation applies to both acidic and basic drugs. It states that the lower the pH relative to the pKa, the greater the fraction of the drug in the protonated non-ionized form will be. Because the uncharged form is more lipid-soluble, acidic drugs will be in the lipid-soluble form at acid pH. In contrast, a basic drug will be in the lipid-soluble form, i.e. unionized at alkaline pH. Incorrect Options: Option B- Small changes in pH near the pKa of a weakly acidic drug will not affect its degree of ionisation: When pH changes near the pKa, the drug's ionization changes significantly. If the pH changes away from pKa, there is a lesser change in ionization of the drug. Option C- Knowledge of the pKa of a drug is not necessary for predicting its behavior in various body fluids: Knowledge of a drug's pKa is always helpful in predicting its behavior in various body fluids, as its penetration in a specific medium depends on the extent of its solubility in that medium. Option D- Phenobarbitone (an acidic drug) with a pKa of 7.2 is largely unionized at alkaline pH: Phenobarbitone is an acidic drug, In an alkaline medium, it will be largely in an ionized form Solution for Question 33: Correct Option B- 400 mg: The distribution volume means the amount of volume required to accommodate the whole drug if the plasma concentration remains uniform throughout that volume. The current plasma concentration is 0.5 mg/L means 1 litre contains 0.5 mg of morphine. Vd of 200 L means 200 litres contains 0.5 x 200 = 100 mg So currently, the total amount of morphine in the body is 100 mg. However, this is the amount present in the body after two half-lives. The half-life is 3 hours, and the patient presented after 6 hours(2 half-lives). After the first T ½, the drug remaining in the body is 50 % of the initial. After the second T ½, the drug remaining in the body is 25 % of the initial. If the initial amount of morphine in the body is x 100 = 25% of x; hence x = 400 mg So the drug present in the body initially was 400 mg. Incorrect Options: Option A- 100 mg: Page 38 38 100 mg is the total amount of drug present in the body currently. Option C- 10 mg: According to the calculation, 400 mg is the correct answer. Option D- 50 mg: This will be the total amount of drugs after 3rd half-lives in the scenario mentioned above. Solution for Question 34: Correct Option B- Volume of distribution: The volume of distribution in the body determines the loading dose of any drug being administered. The distribution volume means how much plasma is required to accommodate the whole drug if the plasma concentration remains constant. The loading dose is a single or few quickly repeated doses given in the beginning to attain the target concentration rapidly. It may be calculated as: Loading dose = volume of distribution x target plasma concentration/fractional bioavailability. Loading dose = volume of distribution x target plasma concentration/fractional bioavailability. Thus, loading dose is primarily governed by the volume of distribution. Loading dose = volume of distribution x target plasma concentration/fractional bioavailability. Incorrect Options: Option A- Drug concentration to be excreted: Loading dose largely depends on the drug concentration to be achieved in a particular volume of distribution rather than the amount to be excreted. Option C- Clearance of the drug: Clearance of the drug does not determine the loading dose, but it's main component when determining the maintenance dose of a drug. Option D- Maintenance dose: Loading dose does not depend on maintenance dose. Solution for Question 35: Correct Option A- Warfarin: Warfarin's TDM does not need to be done as its response can easily be measured by INR monitoring. Therapeutic Drug Monitoring (TDM) is done under the following conditions: When the response of a drug cannot be measured. The drug that has inconsistent pharmacokinetics. Drugs with a narrow therapeutic index (TI), where minor differences in dose can lead to adverse effects. When the response of a drug cannot be measured. Page 39 39 The drug that has inconsistent pharmacokinetics. Drugs with a narrow therapeutic index (TI), where minor differences in dose can lead to adverse effects. The response can be measured in drugs like: Anti-hypertensive drugs: blood pressure can be measured to see their response Anti-diabetic drugs: blood sugar can be measured to see their response Anticoagulants: prothrombin time and INR can be measured to see their response. So, an anticoagulant, warfarin, do not need therapeutic drug monitoring, as its response can be easily measured. Anti-hypertensive drugs: blood pressure can be measured to see their response Anti-diabetic drugs: blood sugar can be measured to see their response Anticoagulants: prothrombin time and INR can be measured to see their response. So, an anticoagulant, warfarin, do not need therapeutic drug monitoring, as its response can be easily measured. So, an anticoagulant, warfarin, do not need therapeutic drug monitoring, as its response can be easily measured. Common indications for warfarin include atrial fibrillation, venous thromboembolism, and prosthetic heart valves. When the response of a drug cannot be measured. The drug that has inconsistent pharmacokinetics. Drugs with a narrow therapeutic index (TI), where minor differences in dose can lead to adverse effects. Anti-hypertensive drugs: blood pressure can be measured to see their response Anti-diabetic drugs: blood sugar can be measured to see their response Anticoagulants: prothrombin time and INR can be measured to see their response. So, an anticoagulant, warfarin, do not need therapeutic drug monitoring, as its response can be easily measured. So, an anticoagulant, warfarin, do not need therapeutic drug monitoring, as its response can be easily measured. So, an anticoagulant, warfarin, do not need therapeutic drug monitoring, as its response can be easily measured. Incorrect Options: Option B- Gentamicin: Gentamicin is an aminoglycoside antibiotic. It has potentially nephrotoxic abilities and needs to be monitored in renal diseases. Option C- Cyclosporin: Cyclosporin is an immunosuppressant drug and has a narrow therapeutic index. So, TDM is necessary. Option D- Phenytoin: Phenytoin, an anticonvulsant, has a narrow therapeutic index, so TDM is necessary. Page 40 40 Solution for Question 36: Correct Option D- Cisapride: Cisapride increases QT interval; if given along with erythromycin, this interaction will make the patient more prone to arrhythmias. Erythromycin is an inhibitor of the microsomal enzyme - CYP3A4 Cisapride works as a stimulant laxative, given in patients with chronic constipation when other laxatives fail to provide adequate relief. CYP3A4 metabolizes cisapride. Cisapride can increase the QT interval. If administered with erythromycin, its metabolism is inhibited, and drug concentration rises. At high plasma concentrations, these drugs block the heart's K+ channel, prolonging QT and possibly Torsades de pointes. Incorrect Options: Option A- Lubiprostone: Lubiprostone is a prostaglandin analogue. It is being used in the treatment of constipation-predominant IBS. It is not affected by erythromycin, as CYP3A4 does not metabolize it. Option B- Streptomycin: Streptomycin is an aminoglycoside antibacterial drug. It is used in the treatment of tuberculosis. Erythromycin does not interfere with its metabolism. Option C- Ebastine: Ebastine is among the second-generation antihistaminics. It also increases QT interval, making it liable to arrhythmogenic potential, and is metabolized CYP3A4. But it is not given as a treatment for constipation. Solution for Question 37: Correct Option A- 12 drops/min: Dose to be given = 10 mcg/min Since one ampoule (5 ml) of 5mg/ml is mixed with normal saline to make a 500 ml volume, Calculations are as follows 500 ml of solution contains = 5 × 5mg = 25 mg NTG 25mg of NTG in 500mL 1mg = 500/25 = 20 mL 1mg = 1000 mcg = 20mL 10mcg = 20/100 = 0.2mL So, we need to infuse 0.2 ml/min of the solution As, 1 ml = 60 drops So, 0.2 ml = 60/1 × 0.2 = 12 drops So, we need to infuse 12 drops/per min 500 ml of solution contains = 5 × 5mg = 25 mg NTG 25mg of NTG in 500mL Page 41 41 1mg = 500/25 = 20 mL 1mg = 1000 mcg = 20mL 10mcg = 20/100 = 0.2mL So, we need to infuse 0.2 ml/min of the solution As, 1 ml = 60 drops So, 0.2 ml = 60/1 × 0.2 = 12 drops So, we need to infuse 12 drops/per min 500 ml of solution contains = 5 × 5mg = 25 mg NTG 25mg of NTG in 500mL 1mg = 500/25 = 20 mL 1mg = 1000 mcg = 20mL 10mcg = 20/100 = 0.2mL So, we need to infuse 0.2 ml/min of the solution As, 1 ml = 60 drops So, 0.2 ml = 60/1 × 0.2 = 12 drops So, we need to infuse 12 drops/per min Solution for Question 38: Correct Option A- Plasma protein binding affects drug distribution: The extent of distribution of a drug depends on the following: Lipid solubility, ionisation at physiological pH, the degree of binding to plasma and tissue proteins, tissue-specific transporter, and regional blood flow differences. Once a drug has gained access to the bloodstream, it gets distributed to other tissues. Movement of the drug proceeds until an equilibrium is achieved between the unbound drug in the plasma and tissue fluids. Drugs extensively bound to plasma proteins are primarily restricted to the vascular compartment. Highly lipid-soluble drugs get initially distributed to organs with high blood flow, i.e. brain, heart, kidney, etc. Later, less vascular but more bulky tissues (muscle, fat) take up the drug. The greater the lipid solubility of the drug, the faster its redistribution. Lipid solubility, ionisation at physiological pH, the degree of binding to plasma and tissue proteins, tissue-specific transporter, and regional blood flow differences. Once a drug has gained access to the bloodstream, it gets distributed to other tissues. Movement of the drug proceeds until an equilibrium is achieved between the unbound drug in the plasma and tissue fluids. Drugs extensively bound to plasma proteins are primarily restricted to the vascular compartment. Highly lipid-soluble drugs get initially distributed to organs with high blood flow, i.e. brain, heart, kidney, etc. Later, less vascular but more bulky tissues (muscle, fat) take up the drug. The greater the lipid solubility of the drug, the faster its redistribution. Page 42 42 Lipid solubility, ionisation at physiological pH, the degree of binding to plasma and tissue proteins, tissue-specific transporter, and regional blood flow differences. Once a drug has gained access to the bloodstream, it gets distributed to other tissues. Movement of the drug proceeds until an equilibrium is achieved between the unbound drug in the plasma and tissue fluids. Drugs extensively bound to plasma proteins are primarily restricted to the vascular compartment. Highly lipid-soluble drugs get initially distributed to organs with high blood flow, i.e. brain, heart, kidney, etc. Later, less vascular but more bulky tissues (muscle, fat) take up the drug. The greater the lipid solubility of the drug, the faster its redistribution. Incorrect Options: Option B- The cell membrane allows more lipid-insoluble molecules to diffuse through it: The cell membrane is a lipid bilayer; hence only lipid-soluble molecules can diffuse through it. Lipid-insoluble compounds need carriers or transporters to cross the cell membrane. Option C- The degree of blood flow does not determine the distribution of a drug: Higher blood flow to organs with high metabolic activity, such as the brain, heart, and kidney, facilitates the initial distribution of highly lipid-soluble drugs. Subsequently, less vascular but more bulky tissues like muscle and fat take up the drug, indicating that increased blood flow contributes to more widespread distribution. Option D- Pathological conditions do not alter the distribution of drug: Pathological states, e.g. congestive heart failure, uremia, cirrhosis, etc., can alter the distribution of many drugs by altering the distribution of body water, the permeability of membranes, or protein bindings. Solution for Question 39: Correct Option B- Clopidogrel: Clopidogrel, a platelet inhibitor, is a prodrug metabolized by CYP2C19 to the active form. CYP2C19 is a gene in the CYP450 system and directly involves the conversion of clopidogrel into its active form. CYP2C19 shows pharmacogenetic variations. Some people are poor metabolizers, and others are extensive metabolizers. Poor metabolites cause inadequate platelet inhibition, but extensive metabolizers may result in bleeding. Drugs that also require CYP2C19 metabolism include omeprazole, lansoprazole, amitriptyline, citalopram, phenytoin, diazepam, propranolol, and clopidogrel. Incorrect Options: Option A- Prasugrel: Prasugrel is an antiplatelet drug. Page 43 43 It works the same as clopidogrel - P2Y12 receptor blocker but does not need CYP2C19 to get activated. Option C- Warfarin: Warfarin is an anticoagulant used to prevent blood clot formation. It does not need CYP2C19 activation. Option D- Omeprazole: Omeprazole is a proton pump inhibitor used to treat peptic ulcer disease. It also needs CYP2C19 for its metabolism but is not an antiplatelet drug Page 44 44 Pharmaco-dynamics 1. Three days after starting a new drug for malaria prophylaxis, a 19-year-old college student had dark-colored urine and fatigue, scleral icterus, and poikilocytes with bite-shaped irregularities. Which drugs will the patient most likely be taking? (or) What drug is the 19-year-old student likely taking if they exhibits dark-colored urine, fatigue, scleral icterus, and irregularities in the peripheral blood smear three days after starting malaria prophylaxis? A. Metronidazole B. Albuterol C. Primaquine D. Erythromycin ---------------------------------------- 2. Which statement accurately describes what can be determined from an individual drug's dose-response curve? (or) Which statement accurately describes what can be determined from an individual drug's dose-response curve? A. Efficacy is the maximum effect produced by a drug regardless of its dose B. Efficacy is the minimum effect produced by a drug regardless of its dose C. A drug is considered more potent if it produces the same response as another drug at a higher dose D. Drugs having steeper DRC have a high therapeutic index ---------------------------------------- 3. Which of the following drugs can be given without the need for therapeutic dose monitoring after calculating the required dose based on the patient's weight, unlike drugs with a narrow therapeutic index? (or) Which of the following drugs can be given without the need for therapeutic dose monitoring after calculating the required dose based on the patient's weight, unlike drugs with a narrow therapeutic index? A. Amikacin B. Penicillin C. Phenytoin D. Cyclosporine ---------------------------------------- 4. Which of the following statements best describes a dose-response curve? (or) Which of the following statements best describes a dose-response curve? A. Dose Response Curve(DRC) has a sigmoid shape 45 B. Area under time and plasma concentration curve signifies the extent of absorption of the drug C. Drug dose is plotted on Y-axis D. Quantal DRC tells about the effect of drugs on an individual ---------------------------------------- 5. A 36-year-old woman with a history of recreational oxycodone use presents with irritability, nausea, and diarrhea, 48 hours after her last dose. Physical examination reveals mydriasis, rhinorrhea, and piloerection. Why does a drug similar to oxycodone, but without euphoria, provide different effects? (or) A 36-year-old woman has mydriasis, rhinorrhea, and piloerection. A drug that provides an effect similar to oxycodone but does not cause euphoria is administered. Which of the following best explains the difference in effect? A. Lower bioavailability B. Lower potency C. Lower efficacy D. Lower affinity ---------------------------------------- 6. A 43-year-old man with epilepsy, stable on phenytoin for 15 years, develops double vision, nystagmus, and gait ataxia after a new medication is added. Which drugs could have been added? (or) A 43-year-old man with a history of epilepsy on stable phenytoin for 15 years presents with new-onset occasional double vision, vertical nystagmus, and gait ataxia after another physician added a medication. What drugs might have been added to his regimen? A. Modafinil B. Nafcillin C. Cimetidine D. Theophylline ---------------------------------------- 7. An investigator is studying the effects of different drugs on the contraction of cardiomyocytes. The myocytes can achieve maximal contractility with the administration of drug A. The administration of drug B produces the response depicted in the graph shown. Which of the following options best describes drug B? (or) The myocytes can achieve maximal contractility with the administration of drug A. The administration of drug B produces the response depicted in the graph shown. Which of the following options best describes drug B? Page 2 46 A. Competitive antagonist B. Non-competitive antagonist C. Partial agonist D. Inverse agonist ---------------------------------------- 8. A 56-year-old man with hypertension takes an oral medication that inhibits the sympathetic activation of β-adrenergic receptors. Which of the following terms best describes a drug that blocks the action of adrenaline at its receptors by occupying them without activating them? (or) Which terms best describes a drug that blocks the action of adrenaline at its receptors by occupying them without activating them? A. Pharmacologic antagonist B. Non-competitive antagonist C. Physiologic antagonist D. Chemical antagonist ---------------------------------------- 9. Which of the following drugs act via the non-receptor tyrosine kinase? (or) An investigator is studying the effects of different drugs on the body. Various drugs are noted that act through the intracellular receptors. Which of the following drugs act via the non-receptor tyrosine kinase? A. Insulin B. Glucagon C. Aldosterone D. Prolactin ---------------------------------------- 10. Adverse drug reactions are unintended pharmacological effects on administering the drug. Which of the following examples refers to a type E adverse drug reaction? (or) Pag

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