Pharmacology Concepts Quiz

In competitive inhibition, the inhibitor binds to the active site of the enzyme, preventing the substrate from binding. This leads to an increase in the EC50 (concentration required for half-maximal effect) while the Vmax (maximum reaction rate) remains unchanged.

Leucovorin, also known as folinic acid, is a reduced form of folic acid that can rescue cells from the toxic effects of methotrexate by providing a different substrate for dihydrofolate reductase.

Diazepam, a benzodiazepine, is used to treat acute alcohol withdrawal symptoms like nausea, tremors, and hallucinations. It works by enhancing the effects of GABA, an inhibitory neurotransmitter, in the brain.

Tizanidine acts as an α2-receptor agonist in the spinal cord, reducing muscle spasm by inhibiting the release of excitatory neurotransmitters like glutamate and acetylcholine.

The question is asking for the total number of tablets required to administer a specific dosage regimen of prednisolone. To determine this, you need to calculate the total milligrams of prednisolone needed for each day and then figure out how many tablets of each strength are required to achieve that dosage.

The posterior pituitary gland stores and releases two hormones: antidiuretic hormone (ADH), which regulates water balance, and oxytocin, which plays a role in childbirth and lactation.

Mevalonate is an early intermediate in cholesterol biosynthesis. It's formed from acetyl-CoA, and subsequent steps lead to squalene and lanosterol before cholesterol synthesis is complete.

To deliver a single dose of 10 mg from a 6% w/v solution, use the formula: Desired dose (mg) / Concentration (% w/v) = Volume (mL). Therefore, 10 mg / 6% = 1.67 mL. The closest option is 1.6 mL, so the answer is approximately 0.16 mL.

To calculate the amount of hydrocortisone powder needed to increase the concentration of the ointment from 1% to 4%, first calculate the difference in concentration (4% - 1% = 3%). Then multiply this difference by the initial weight of the ointment (3% * 200 g = 6 g).

Transcription is the process of copying genetic information from DNA (deoxyribonucleic acid) into RNA (ribonucleic acid). It's the first step in gene expression, where DNA's code is transcribed into a messenger RNA molecule that can be used to make proteins.

Vitamin A, also known as retinol, is crucial for maintaining healthy vision. Deficiency can lead to night blindness and eventually irreversible blindness.

Cigarette smoking induces the activity of CYP1A2, an enzyme that metabolizes many medications. This increased metabolism can lead to lower plasma concentrations of various drugs, including clozapine, olanzapine, and methadone. However, digoxin is not metabolized by CYP1A2 to a significant extent, so its plasma concentration is not affected by cigarette smoking.

Niacin deficiency causes pellagra, a disease characterized by the “three Ds”: dermatitis, diarrhea, and dementia.

To calculate the volume of distribution (Vd), use the formula: Vd = Dose / Peak Concentration. In this case, Vd = 200 mg / 4 mg/L = 50 L. Therefore, the volume of distribution of phenytoin for this patient is 50 L.

The loading dose for a drug is calculated using the formula: Loading Dose = Target Concentration × Vd. In this case, the target concentration is between 7 and 9 mg/L, and the Vd is 0.25 L/kg × (143 lb / 2.2 lb/kg) = 16.2 kg. Therefore, the loading dose should be between 113 mg and 146 mg.

Filgrastim, a granulocyte colony-stimulating factor (G-CSF), promotes the production and release of neutrophils from the bone marrow. It is used to manage neutropenia, a decrease in neutrophils, which can occur during chemotherapy, especially with drugs like zidovudine.

Abciximab is a monoclonal antibody that prevents platelet aggregation by inhibiting the binding of fibrinogen to the platelet surface. This action helps prevent blood clots in patients undergoing coronary interventions.

Ferritin is a protein found in the liver, spleen, and bone marrow that stores iron. It serves as the primary iron storage depot in the body, providing a reserve when iron levels are low.

Iron deficiency anemia is characterized by low red blood cell count, low hemoglobin levels, and low serum ferritin levels. As the body struggles to produce enough red blood cells, the total iron-binding capacity (TIBC) increases to compensate for the iron deficiency.

Deferoxamine is a chelating agent that binds to iron, effectively removing excess iron from the body. It is used to manage transfusional iron overload, which can occur in patients who receive frequent blood transfusions and accumulate iron.

Filgrastim is a granulocyte colony-stimulating factor (G-CSF) that stimulates the bone marrow to produce more neutrophils. It is used in cancer patients to help recover neutrophil counts after chemotherapy, which often causes neutropenia, a decrease in neutrophils.

FOBT (fecal occult blood test), also known as a guaiac smear test, is used to screen for colorectal cancer. It detects the presence of hidden blood in the stool, which can be an early sign of colorectal cancer.

Lithium, a mood stabilizer, is known to be sensitive to interactions with other medications. NSAIDs, thiazide diuretics, ACE inhibitors, and low sodium intake can increase lithium levels in the blood, potentially leading to toxicity. While increasing sodium intake can generally help reduce lithium levels, it's essential to note that these interactions are complex and require careful monitoring by healthcare professionals.

Digoxin, a cardiac glycoside, binds to sodium/potassium-ATPase, an enzyme involved in regulating the transport of sodium and potassium ions across cell membranes. This binding alters the electrical activity of the heart, leading to a slower heart rate and improved contraction strength in patients with heart failure.

Digoxin can interact with other medications, increasing the risk of toxicity. Amiodarone, verapamil, and quinidine also affect heart rhythm and can enhance digoxin's effects on the heart. However, colestipol, a bile acid sequestrant, does not interact with digoxin and does not pose an increased risk of toxicity.

Glucagon, a hormone secreted by the pancreas, plays a crucial role in gluconeogenesis, the process of producing glucose from non-carbohydrate sources like lactate, amino acids, and glycerol. This occurs in the liver and helps maintain blood glucose levels when there is low blood sugar.

Oprelvekin, a thrombopoietin receptor agonist, promotes platelet production by activating receptors on megakaryocytes, the precursors of platelets. It is used to stimulate platelet production in patients with chemotherapy-induced thrombocytopenia (low platelet count).

Valproic acid, an anticonvulsant, inhibits glucuronidation, a key process in the metabolism of lamotrigine, another anticonvulsant. This interaction results in higher lamotrigine plasma levels, requiring careful monitoring of lamotrigine dosage in patients taking valproic acid.

Terbinafine, an antifungal medication, is not known to be hepatotoxic. However, other drugs like dronaderone, valproic acid, and lithium can cause liver damage, making it crucial to monitor liver function in patients taking these medications.

In a two-compartment IV model, the drug distributes between a central compartment (bloodstream) and peripheral compartment (other tissues). The log plasma concentration-time graph exhibits two phases: a distribution phase with rapid distribution and an elimination phase with gradual elimination. The absorption phase is absent because the drug is administered intravenously. The concentration equation is based on two exponential terms, reflecting the two compartments.

To calculate the gentamicin plasma concentration after 4 hours, use the formula: Concentration at time t = Dose x Vd / (Vd x (1 - exp(-k x t))), where k is the elimination rate constant (ln2 / half-life). First, calculate k: k = ln2 / 3 h = 0.231 h-1. Then, plug in the values: Concentration at 4 h = (5 mg/kg x 0.20 L/kg) / (0.20 L/kg x (1 - exp(-0.231 h-1 x 4 h))) = 3.2 mg/L. However, the answer should be in mcg/L so we multiply 3.2 by 1000 to get 3200 mcg/L.

To determine the administered dose, use the formula: Dose = Concentration x Vd x exp(k x t). First, calculate the elimination rate constant: k = ln2 / half-life = ln2 / 4 h = 0.173 h-1. Then, plug in the values: Dose = 1 mcg/mL x 2.25 L/kg x exp(0.173 h-1 x 6 h) = 7.9 mg/kg. The unit mL should be converted to L, but since the Vd is in L/kg, the mL cancel out on the equation.

Absolute bioavailability (F) is the fraction of an orally administered drug that reaches systemic circulation compared to the same dose administered intravenously. It is calculated using the formula: F = (AUCoral x DoseIV) / (AUCIV x DoseOral), where AUC refers to the area under the plasma concentration-time curve. In this case, F = (126.4 mg.h/mL x 42.5 mg) / (35.84 mg.h/mL x 150 mg) = 0.80.

Streptococcus pyogenes, also known as group A streptococcus, is a common cause of bacterial sore throat (strep throat). It is susceptible to treatment with penicillin G, but if not treated, it can cause more serious complications.

Doxycycline, a broad-spectrum antibiotic, is effective against a wide range of bacteria, including Chlamydia trachomatis. This bacterium is a common cause of sexually transmitted infections (STIs), including urethritis in men and cervicitis in women.

Staphylococcus aureus is a common cause of mastitis, a breast infection that often occurs after childbirth. Staphylococcus aureus can produce toxins and cause a range of infections, including skin infections, food poisoning, and pneumonia.

Ampicillin, a penicillin-type antibiotic, and gentamicin, an aminoglycoside antibiotic, are both effective against Enterococcus faecalis, a common cause of urinary tract infections (UTIs). Combining these antibiotics can address both susceptible Enterococcus faecalis and any accompanying gram-negative bacteria that may contribute to the UTI.

Pasteurella multocida is a common bacterium found in the mouths of dogs and cats, often leading to infections after bites. Amoxicillin/clavulanate, a combination antibiotic, is typically used to treat infections caused by Pasteurella multocida., as the clavulanate component inhibits the breakdown of amoxicillin, enhancing its effectiveness.

Moxifloxacin, a fluoroquinolone antibiotic, is effective against a range of bacteria, including Treponema pallidum, the causative organism of syphilis. Syphilis is a sexually transmitted disease that can cause painless ulcers known as chancres.

Trastuzumab is a monoclonal antibody that targets HER-2 (human epidermal growth factor receptor 2), a protein often overexpressed in breast cancer cells. By binding to HER-2, trastuzumab inhibits cell growth and can improve survival in patients with HER-2 positive breast cancer.

Doxorubicin, an anthracycline antibiotic, is a chemotherapy drug that works by intercalating between DNA strands, inhibiting the action of topoisomerase II. This prevents DNA replication and ultimately leads to cell death.

Leuprolide, a gonadotropin-releasing hormone (GnRH) agonist, is used to treat prostate cancer by suppressing testosterone production. However, while lowering testosterone levels can provide therapeutic benefits, it can also cause side effects like hot flashes due to a reduction in estrogen levels.

Goserelin, another GnRH agonist, inhibits the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. This suppression of FSH and LH ultimately reduces testosterone production, which is beneficial in the treatment of prostate cancer.

The mean corpuscular volume (MCV) is a laboratory test that measures the average volume of red blood cells. It helps determine whether anemia is microcytic (small red blood cells), normocytic (normal-sized red blood cells), or macrocytic (large red blood cells).

Iron deficiency anemia is characterized by a low serum ferritin level, indicating low iron stores. As the body tries to compensate for the iron deficiency, the total iron-binding capacity (TIBC) increases to bind more iron.

Doxorubicin, a chemotherapy drug, can cause heart damage, leading to symptoms like shortness of breath after lying down (orthopnea), rapid heartbeat (tachycardia), fluid buildup in the lungs and ankles (pulmonary and ankle edema), and general fatigue. These symptoms indicate heart failure, a serious complication of doxorubicin treatment.

Etoposide, a topoisomerase II inhibitor, prevents the repair of broken strands of DNA. This disruption of DNA repair leads to cell death, particularly in rapidly dividing cancer cells.

Idarucizumab is a monoclonal antibody that specifically binds to dabigatran, a direct thrombin inhibitor. This binding effectively reverses the anticoagulant effects of dabigatran, allowing for rapid reversal of bleeding in patients who require urgent reversal of their anticoagulation status.

Carbamazepine, an anticonvulsant, induces its own metabolism by increasing the activity of certain CYP enzymes. As a result, the initial dose may be lower than the maintenance dose, which is typically higher to achieve therapeutic blood levels.

Glucuronyltransferase is a key enzyme involved in Phase II metabolic reactions, specifically conjugation reactions where a glucuronic acid molecule is attached to a drug molecule. It is involved in the detoxification and elimination of many drugs.

Angiotensin-converting enzymes (ACE) are a group of enzymes that do not contain heme. While they play a vital role in regulating blood pressure, ACEs are not heme-containing proteins.

Keto-enol tautomerism is a type of isomerism where a ketone and an enol form are interconvertible. This equilibrium is influenced by the presence of acidic or basic catalysts. In the case of acetone, it can exist in both keto and enol forms, with the keto form predominating.

Octreotide is a synthetic somatostatin analog that is administered intravenously or subcutaneously, not orally. It is used to manage acromegaly, a disorder caused by excessive growth hormone production, and to treat severe diarrhea associated with certain conditions. It does not increase growth hormone secretion.

Epinephrine, a potent vasoconstrictor and heart stimulant, is the appropriate antidote for bisoprolol overdose. It works by counteracting the effects of bisoprolol, a beta-blocker, which lowers heart rate and blood pressure.

Atropine, an anticholinergic drug, and pralidoxime, an acetylcholinesterase reactivator, are the antidotes for parathion poisoning. Parathion is an organophosphate insecticide that inhibits acetylcholinesterase, leading to a buildup of acetylcholine in the synapses, causing a wide range of symptoms.

Amitriptyline is a tricyclic antidepressant that can cause confusion, hypotension, seizures, and cardiac arrhythmias in overdose. These symptoms are due to its anticholinergic properties and its effects on the cardiovascular system.

Increased levels of thyroid-stimulating hormone (TSH) can cause weight loss, difficulty sleeping, and nervousness. The body compensates for a low thyroid hormone production by releasing more TSH in an attempt to stimulate the thyroid gland.

Glutathione addition is a Phase II metabolic reaction where glutathione, a tripeptide, is conjugated to a drug molecule. This conjugation often increases the water solubility of the drug, making it easier to excrete from the body.

DNA replicates during the S phase of the cell cycle. During S phase, the cell's entire genome is copied, ensuring that each daughter cell inherits a complete set of chromosomes.

Chancroids is a sexually transmitted disease caused by Haemophilus ducreyi, a gram-negative bacterium. It is characterized by painful, soft sores on the genitals.