Pharmacology Week 1 Notes PDF

**Pharmacology week 1 notes** **Chapter 2, pharmacology principles** Drug -- any chemical that affects the physiological processes of a living organism Pharmacology -- broadest term for the study or science of drugs Chemical name: describes the drugs chemical composition and molecular structure...

**Pharmacology week 1 notes** **Chapter 2, pharmacology principles** Drug -- any chemical that affects the physiological processes of a living organism Pharmacology -- broadest term for the study or science of drugs Chemical name: describes the drugs chemical composition and molecular structure Generic name/non-proprietary name: name given to drug approved by health Canada, example, acetaminophen Trade name: the drug has a registered trademark, example, Tylenol. [Pharmaceutics: ] - Dosage form determines the rate at which drug dissolution occurs - A drug to be ingested orally may be in either a solid form (tablet, capsule, or powder) or a liquid form (solution or suspension) - Oral drugs that are liquids (e.g., elixirs, syrups) are already dissolved and are usually absorbed more quickly than solid dosage forms - Enteric-coated tablets have a coating that prevents them from being broken down in the acidic pH environment of the stomach and therefore are not absorbed until they reach the more alkaline pH of the intestines  slower dissolution and slower absorption [Rate of absorption based on drug form: from fastest to slowest ] Liquid, suspension solutions, Powders, capsules, tablets, coated tablets and enteric coated tablets. **[Drug delivery systems]** Combination drugs -- multiple drugs in one dose Time-release technology -- tablets and capsules capable of releasing drug molecules into the GI tract over an extended period of time  Released continuously and more slowly into blood stream Prolonged drug absorption Prolonged duration of action Easily identified by capital letter abbreviations These forms require fewer daily doses - Thin-film drug delivery - Products that dissolve in the mouth - Absorbed by oral mucosa when contact with liquid occurs - Examples - oral disintegrating tablets, thin wafers - Administered and dissolve on the tongue, under the tongue, or in the buccal (cheek) pocket Acronyms SR -- slow release or sustained release SA -- sustained action CR -- controlled release XL -- extended length XT -- extended time IMPACT OF DOSAGE FORM - For a drug to work at a specific site in the body it must either 1. Be applied directly at that site in an active form 2. Have a way of getting to that site **Oral:** **Topical:** - Some topically applied dosage forms work directly on the surface of the skin (immediate action) - Skin acts as a barrier with some topical dosage forms drug must pass to get to the circulation; one there, the drug is carried to the site of action **Parental:** - Delivered via injection - Arteries and veins can be easily damaged if the drug is too concentrated or corrosive - Intravenous administration are directly placed in the bloodstream and absorption occurs immediately PHARMACOKINETICS: Pharmacokinetics: The study of what happens to a drug from the time it is put into the body till the parent drugs and its metabolites leave the body. There are 4 steps: - Absorption - Distribution - Metabolism - Excretion **Absorption.** - Absorption -- the movement of a drug from its site of administration into the bloodstream for distribution to tissues - Bioavailability -- extent of drug absorption - A drug absorbed from the intestine must pass through the liver before it reaches to systemic circulation - If the drug is chemically changed in the liver, a smaller amount will pass into the circulation (i.e., will be bioavailable) This is called first pass effect. - Intravenous drugs are 100% bioavailable because 100% of the drug reaches the systemic circulation - Oral drugs have reduced bioavailability -- only a fraction reaches systemic circulation - **How a drug is administered, or its route of administration, affects the rate and extent of absorption of that drug** **Enteral (GI tract):** Tablets, capsules, oral soluble wafers, pills, time-release capsules, time-release tablets, enteric-coated tablets, elixirs, suspensions, solutions, lozenges or troches, caplets, rectal\* suppositories, sublingual or buccal tablets **Parental:** Injectable forms, solutions, suspensions, emulsions, powders for reconstitution **Topical**: Aerosols, ointments, creams, pastes, powders, solutions, foams, gels, transdermal patches, inhalers, rectal\* and vaginal suppositories. ROUTES OF ADMINISTRATION AND NURDING CONSIDERATIONS **Intravenous (IV)** - Frequent monitoring of volume and amount are administered - Monitor therapeutic blood levels - Check for compatibility - Monitor for redness, swelling, heat, and drainage - Flush line post medication administration **Intramuscular (IM)** - Landmark appropriately - In adults the site of choice is the ventral gluteal muscle - Deltoid muscle in the upper arm is site of choice for vaccine administration (adults) **Subcutaneous (SC:** - Landmark appropriately - Common sites include the lateral and posterior aspects of the upper arm and under the greater trochanter of the femur in the thigh and abdominal area - Given at a 90-degree angle; in emaciated or extremely thin patients, the subcutaneous angle is 45 degrees **Oral (PO)** - With/without food - Sufficient fluid (180 to 240mL) of water - Other medicines taken at the same time and concurrent use of dairy products or antacids - NG or g-tube - Check placement - HOB elevated - Flushing pre/post to maintain patency of tube/prevent clogging - Enteric-coated can\'t be crushed (switch to liquid form) **Sublingual** - Dissolve under the tongue - Once dissolved, can swallow **Rectal** - Erratic and unpredictable absorption rate - Safe alternative when N&V prevents oral administration - Left side so normal anatomy of colon allows safe and effective insertion - Insert using a gloved hand or index finger and water-soluble lubricant **Topical** - Solution, ointment, spray, drops - Max absorption when skin is clean and free of debris - Gloves help minimize cross-contamination and prevent absorption into the nurse\'s own skin - Sterile technique may be needed **Transdermal** - Placed on alternating sites on clean, non-hairy, non-irritated area - Write date/time and initials when applying - Wear gloves to prevent absorption into the nurse's own skin **Inhalation:** - Proper teaching to patient and/or family members for correct usage - Use of spacers and nebulizers can help with absorption **Distribution** - Distribution -- the transport of a drug by the bloodstream to its site of action - Distributed first to those areas with extensive blood supply - Heart, liver, kidneys, and brain - Slower distribution to muscle, skin, and fat - Some sites in the body which may be difficult to distribute a drug - Poor blood supply (e.g., bones) - Physiological barriers that make it difficult to pass through (e.g., blood-brain barrier) In the blood, meds can be bound or unbound. - A drug can be bound to certain proteins when not ready to be used for target system. - Albumin level can influence how much free bound medication is available - Places where it's hard to distribute drub can be due to poor blood flow. - Distribution: how much of drug is free floating, so it can go to its target. **Metabolism** - Metabolism -- involves the biochemical alteration of a drug into: - An inactive metabolite - A more soluble compound - More potent metabolite - Less active metabolite - Liver is most responsible for metabolism - Skeletal muscles, kidneys, lungs, plasma, and intestinal mucosa can also metabolize drugs - Age, genetics, diseases, and/or concurrent use of other medications can alter liver's metabolism abilities Body changes drug to different forms and changes potency \- It can completely inactivate it \- Make it more soluble, from frat soluble to water soluble \- Organ responsible is liver \- Liver involvement- know patient baseline liver function. Baseline liver function, we want to understand where they're at in their liver health. New onset vs long term liver failure. Look at how it is and how is has been to know the trajectory. Liver metabolism- be mindful of age, Liver slows down with age, usually after age 60. Less amount of medication being given due to age. Water soluble medication is easier to metabolism than fat soluble medication. **Excretion:** - Excretion -- elimination of drugs from the body - Kidneys are mostly responsible for elimination of drugs - Most drugs metabolized in the liver by the time the drugs get to the kidneys, they have undergone extensive biotransformation (drug converted to a less active form) and only a small fraction of the original drug is excreted - More polar and water-soluble - Some drugs bypass hepatic (liver) metabolism reach kidneys in original form - Biliary excretion -- drugs taken up by the liver, released in the bile, eliminated in the feces Only unbound drugs are being excreted. - \- Sometimes it takes additional metabolism so it can be unbound and be excreted - \- Some drugs bypass metabolisms. - Focus on kidney health when assessing excretion of a drug - Look at patients with reduced kidney function. - Lower value means higher risk for toxicity. Half-life: - Half-life -- the time required for serum drug levels to be reduced by one-half (50%) during the elimination phase - Measure of the rate at which the drug is eliminated from the body - Steady state -- refers to the physiological state in which the amount of drug removed via elimination is equal to the amount of drug absorbed with each dose Onset, peak and duration Drug actions: - The processes involved in the interaction between a drug and a cell (e.g., a drug's action on a receptor) Onset of actions: - Time required for the drug to elicit a therapeutic response Peak effect: - Time required for it to reach its maximal therapeutic response Duration of action: - Length of time that its concentration is sufficient (without more doses) to elicit a therapeutic response DRUG TOXICITY - Length of time until the onset, peak of action, and duration of action play an important part in determining the peak level (highest blood level) and trough level (lowest blood level) of a drug - If the peak blood level is too high drug toxicity - Toxicity can be mild -- intensification of effects of the drug (e.g., excessive sedation resulting from overdose of a drug) - Toxicity can be severe -- damage to vital organs to due excessive drug exposure - If the trough blood level is too low drug may not be at therapeutic level to produce a response - Therapeutic drug monitoring is required to verify adequate drug exposure, maximize therapeutic effects, and minimize drug toxicity PHARMACODYNAMICS: - Pharmacodynamics -- the relationship between drug concentrations and the pharmacological response (actions of the drug) - A positive change in a faulty physiological system is called a therapeutic effect (goal of drug therapy) - Effects of drugs depend on the cells/tissues targeted - When drug is at the site of action, it can - Modify (increase/decrease) the rate at which the cell or tissue functions - Modify the strength of function of that cell or tissue - Cannot cause a cell or tissue to perform a function that is not part of its natural physiology - Drugs can act on receptors, enzymes, and nonselective interactions **Mechanisms of action** Receptor - a reactive site on the surface or inside of a cell - Once a drug binds and interacts with the receptor, a pharmacological response is produced Enzyme -- substances that catalyze biochemical reactions in a cell - Enzyme interactions can inhibit (most common) or enhance (less common) the action of a specific enzyme Nonselective interaction -- target cell membranes and cellular processes **[Drug type and action: ]** Against: - Drug binds to receptor, there is response Partial agonist: - Drug binds to receptor, response is diminished compared to response elicited by agonist Antagonist: - Drug binds to receptor, there is no response. Drug prevents binding of agonist Competitive antagonist: - Drug competes with agonist to bind to receptor. If binds, no response. Non-competitive antagonist: - Drug combines with different parts of the receptor and inactivates it. Agonist has no effect even if it binds. PHARMACOTHERAPEUTICS - Establish an end point or expected outcome of therapy - Curing a disease - Eliminating or reducing a pre-existing symptom - Arresting or slowing a disease process - Preventing a disease or other unwanted condition - Improving quality of life - Contraindication -- any patient condition, especially a disease state that makes the use of the medication dangerous for the patient - Use of over-the-counter drugs, natural health products, illicit drugs, prescription drugs, pregnancy and breastfeeding status, etc. **Monitoring** - Effectiveness of therapy must be evaluated - Drug's intended therapeutic action - Drug's unintended possible adverse effects (e.g., drug reaction) - Drug interactions - Drugs can interact with other drugs, food, or agents administered as part of lab tests - More drugs a patient receives, the more likely that a drug interaction will occur - Drug interactions can increase or decrease the action of one or both drugs Additive effects (1+1=2) - Drug interaction in which the effect of a combination of two or more drugs with similar actions, administered at the same time, is the action of one plus the action of the other, with the total effect of both drugs being given Synergistic effects (1+1= greater than 2) - When the action of one drug enhances the action of another Antagonistic effects (1+1= less than 2) - When the combination of two drugs results in drug effects that are less than the sum of the effects for each drug given separately Incompatibility - When wo parenteral drugs or solutions are mixed together, and the result is a chemical deterioration of one or both of the drugs PRACTICE QUESTIONS: 1. **A nurse is administering an oral medication. Which dosage form is expected to be absorbed the fastest?** - A\) Enteric-coated tablet - B\) Capsule - C\) Liquid solution - D\) Powder 2. **What is the primary organ responsible for drug metabolism?** - A\) Kidneys - B\) Lungs - C\) Liver - D\) Heart 3. **A patient is prescribed a medication that undergoes significant first-pass metabolism. Which route of administration would provide the most bioavailability?** - A\) Oral - B\) Intravenous - C\) Sublingual - D\) Intramuscular 4. **A nurse is preparing to administer a time-release capsule. What is an important nursing consideration?** - A\) It can be crushed for easier administration. - B\) It should be administered with food. - C\) It must be given at regular intervals for optimal effect. - D\) It should not be crushed or chewed. 5. **When considering the distribution of a drug, which area of the body receives it first?** - A\) Skin - B\) Muscles - C\) Brain - D\) Adipose tissue 6. **A patient with liver dysfunction is prescribed a medication metabolized by the liver. What should the nurse monitor?** - A\) Blood glucose levels - B\) Liver function tests - C\) Electrolyte levels - D\) Renal function tests 7. **A nurse explains the importance of knowing a drug's half-life to a patient. Which statement is correct?** - A\) It determines the drug's therapeutic effect. - B\) It measures how long the drug remains effective in the body. - C\) It indicates how quickly the drug is eliminated. - D\) It reflects the drug\'s potential for toxicity. 8. **Which of the following statements about pharmacodynamics is true?** - A\) Drugs can create new functions in cells. - B\) Drugs modify existing physiological functions. - C\) All drugs have the same mechanism of action. - D\) Drug interactions do not affect pharmacodynamics. 9. **A patient on anticoagulant therapy is prescribed an antibiotic that has additive effects. What does this mean?** - A\) The antibiotic enhances the action of the anticoagulant. - B\) The antibiotic negates the effects of the anticoagulant. - C\) The combined effect is equal to the sum of each drug\'s effect. - D\) The combined effect is less than the sum of each drug\'s effect. 10. **A nurse is administering a drug with a known peak effect time of 2 hours. When should the nurse evaluate the patient for therapeutic response?** - A\) 30 minutes after administration - B\) 1 hour after administration - C\) 2 hours after administration - D\) 4 hours after administration 11. **What is the primary purpose of enteric-coated tablets?** - A\) To enhance absorption in the stomach - B\) To prevent breakdown in the stomach\'s acidic environment - C\) To allow for faster dissolution - D\) To make the medication taste better 12. **A nurse is assessing a patient with decreased renal function. Which aspect of pharmacokinetics is most affected?** - A\) Absorption - B\) Distribution - C\) Metabolism - D\) Excretion 13. **A patient is experiencing excessive sedation after a dose of medication. What is the most likely cause?** - A\) Synergistic effect - B\) Antagonistic effect - C\) First-pass metabolism - D\) Toxicity 14. **Which of the following routes of administration provides the most immediate effect?** - A\) Oral - B\) Subcutaneous - C\) Intramuscular - D\) Intravenous 15. **Which of the following would be considered a contraindication for a prescribed medication?** - A\) Age over 60 - B\) Previous allergic reaction to a similar drug - C\) Current medication regimen - D\) Patient's weight 16. **A nurse is teaching a patient about their oral medication regimen. Which instruction is essential?** - A\) Take medications only when symptoms arise. - B\) Crush enteric-coated tablets for better absorption. - C\) Take medications with a full glass of water. - D\) Skip doses if side effects occur. 17. **Which statement about the pharmacological action of a drug is correct?** - A\) A drug can change a cell's natural function. - B\) A drug can only enhance or inhibit existing cellular functions. - C\) All drugs work on the same receptors. - D\) The effects of a drug are consistent across all patients. 18. **A nurse is administering a medication with a short half-life. How often will this medication need to be administered?** - A\) Every 12 hours - B\) Every 4 hours - C\) Every 24 hours - D\) Once a day 19. **Which factor can affect the metabolism of a drug?** - A\) Route of administration - B\) Time of day - C\) Patient's hydration status - D\) Concurrent use of other medications 20. **When administering a sublingual medication, which nursing action is appropriate?** - A\) Offer water to aid swallowing. - B\) Ensure the patient does not eat or drink until dissolved. - C\) Crush the medication for faster absorption. - D\) Administer the medication through a feeding tube. 21. **What should the nurse monitor in a patient receiving a medication with a narrow therapeutic index?** - A\) Heart rate and rhythm - B\) Serum drug levels - C\) Blood pressure - D\) Liver function tests 22. **What is the expected outcome of pharmacotherapy aimed at reducing a symptom?** - A\) Curing a disease - B\) Improving quality of life - C\) Preventing a condition - D\) Enhancing physiological function 23. **A nurse is teaching about the absorption of oral medications. Which statement is correct?** - A\) All oral medications are absorbed in the stomach. - B\) Liquid medications are generally absorbed faster than solid forms. - C\) Enteric-coated medications dissolve in the stomach. - D\) The gastrointestinal environment has no effect on absorption. 24. **Which of the following describes a non-competitive antagonist?** - A\) Competes with an agonist for the same binding site. - B\) Binds to a different part of the receptor, preventing activation. - C\) Enhances the effect of an agonist. - D\) Completely blocks all receptor activity. 25. **A patient is being treated for chronic pain with a sustained-release medication. What should the nurse advise the patient?** - A\) Take an extra dose if pain increases. - B\) Stop taking the medication if side effects occur. - C\) Do not crush or chew the tablet. - D\) Expect rapid relief of pain. 26. **What is the purpose of therapeutic drug monitoring?** - A\) To ensure that drugs are administered at the correct time. - B\) To verify adequate drug exposure and minimize toxicity. - C\) To evaluate a patient's adherence to the medication regimen. - D\) To determine the route of administration. 27. **A patient is prescribed a new medication. What is the nurse\'s best action before administration?** - A\) Educate the patient about potential side effects. - B\) Administer the medication without further assessment. - C\) Confirm the patient's understanding of the drug\'s purpose. - D\) Review the patient\'s previous medication history. 28. **Which of the following is true regarding the pharmacokinetics of a drug?** - A\) All drugs are absorbed at the same rate regardless of the form. - B\) Drugs are metabolized primarily in the kidneys. - C\) Excretion primarily occurs through urine and feces. - D\) Distribution is uniform across all body tissues. 29. **A nurse is educating a patient about a new medication regimen. What should the nurse include regarding potential drug interactions?** - A\) Most drug interactions only occur with over-the-counter medications. - B\) Drug interactions are rare and not a significant concern. - C\) All medications should be reported to the healthcare provider. - D\) Only prescription medications need to be monitored for interactions. 30. **A patient is receiving a medication that has a known toxic effect. What is a key nursing action?** - A\) Monitor for signs of therapeutic effectiveness only. - B\) Educate the patient about the potential for toxicity. - C\) Administer the medication at higher doses for better effect. - D\) Discontinue the medication if side effects occur. **Select All That Apply Questions** 1. **Which of the following are true about the first-pass effect? (Select all that apply)** - A\) It reduces the bioavailability of oral medications. - B\) It occurs in the liver. - C\) It affects all routes of administration equally. - D\) It is a process of drug metabolism. 2. **What are potential factors that can influence drug metabolism? (Select all that apply)** - A\) Age - B\) Genetics - C\) Diet - D\) Route of administration 3. **Which factors should the nurse consider when administering medications to elderly patients? (Select all that apply)** - A\) Reduced liver function - B\) Increased body fat - C\) Decreased gastric pH - D\) Enhanced renal clearance 4. **Which of the following are characteristics of sustained-release medications? (Select all that apply)** - A\) They provide prolonged drug absorption. - B\) They can be crushed or chewed for faster release. - C\) They require fewer daily doses. - D\) They are designed to release medication over an extended period. 5. **Which of the following statements about drug interactions are true? (Select all that apply)** - A\) Drug interactions can occur with food. - B\) All drug interactions result in toxicity. - C\) Polypharmacy increases the risk of interactions. - D\) Some interactions can enhance therapeutic effects. 6. **Which of the following are nursing considerations when administering topical medications? (Select all that apply)** - A\) Clean the skin before application. - B\) Wear gloves to prevent contamination. - C\) Apply to hairy areas for better absorption. - D\) Monitor for local reactions. 7. **Which factors can affect a patient's response to medication? (Select all that apply)** - A\) Body weight - B\) Ethnicity - C\) Medication adherence - D\) Time of day medication is taken 8. **What are possible adverse effects of drug toxicity? (Select all that apply)** - A\) Nausea - B\) Organ damage - C\) Sedation - D\) Elevated blood pressure 9. **Which nursing interventions are essential when administering intravenous medications? (Select all that apply)** - A\) Monitor for signs of infiltration. - B\) Flush the line before and after administration. - C\) Check compatibility of medications. - D\) Administer medication without checking patient ID. 10. **What should the nurse include in patient education regarding medications? (Select all that apply)** - A\) Importance of adherence to the regimen - B\) Potential side effects and when to report them - C\) The need for routine blood tests - D\) The effects of herbal supplements on prescribed medications Multiple Choice Answers 1. C\) Liquid solution 2. C\) Liver 3. B\) Intravenous 4. D\) It should not be crushed or chewed. 5. C\) Brain 6. B\) Liver function tests 7. C\) It indicates how quickly the drug is eliminated. 8. B\) Drugs modify existing physiological functions. 9. C\) The combined effect is equal to the sum of each drug\'s effect. 10. C\) 2 hours after administration 11. B\) To prevent breakdown in the stomach\'s acidic environment 12. D\) Excretion 13. D\) Toxicity 14. D\) Intravenous 15. B\) Previous allergic reaction to a similar drug 16. C\) Take medications with a full glass of water. 17. B\) A drug can only enhance or inhibit existing cellular functions. 18. B\) Every 4 hours 19. D\) Concurrent use of other medications 20. B\) Ensure the patient does not eat or drink until dissolved. 21. B\) Serum drug levels 22. B\) Improving quality of life 23. B\) Liquid medications are generally absorbed faster than solid forms. 24. B\) Binds to a different part of the receptor, preventing activation. 25. C\) Do not crush or chew the tablet. 26. B\) To verify adequate drug exposure and minimize toxicity. 27. A\) Educate the patient about potential side effects. 28. C\) Excretion primarily occurs through urine and feces. 29. C\) All medications should be reported to the healthcare provider. 30. B\) Educate the patient about the potential for toxicity. Select All That Apply Answers 1. A\) It reduces the bioavailability of oral medications.\ B) It occurs in the liver. 2. A\) Age\ B) Genetics\ C) Diet 3. A\) Reduced liver function\ B) Increased body fat\ C) Decreased gastric pH 4. A\) They provide prolonged drug absorption.\ C) They require fewer daily doses.\ D) They are designed to release medication over an extended period. 5. A\) Drug interactions can occur with food.\ C) Polypharmacy increases the risk of interactions.\ D) Some interactions can enhance therapeutic effects. 6. A\) Clean the skin before application.\ B) Wear gloves to prevent contamination. 7. A\) Body weight\ B) Ethnicity\ C) Medication adherence\ D) Time of day medication is taken 8. A\) Nausea\ B) Organ damage\ C) Sedation 9. A\) Monitor for signs of infiltration.\ B) Flush the line before and after administration.\ C) Check compatibility of medications. 10. A\) Importance of adherence to the regimen\ B) Potential side effects and when to report them\ C) The need for routine blood tests