Pharmacology and Drug Interactions Quiz
44 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a primary goal in managing drug-drug interactions?

  • Ignore potential side effects
  • Only monitor drug levels after therapy begins
  • Prevent clinically significant interactions (correct)
  • Maximize dosage of all medications

    • Activated Phase II transformations decrease the water solubility of xenobiotic compounds.

    False

    Name one major endogenous antioxidant mentioned in the content.

    Glutathione

    Hepatotoxicity is caused by chemical-driven liver damage due to exposure to reactive metabolites formed by _______ enzymes.

    <p>CYP450</p> Signup and view all the answers

    Match the following substances with their roles in detoxification or metabolism:

    <p>Glutathione = Detoxifies xenobiotics and carcinogens Glucuronic acid = Conjugation for excretion of drugs and pollutants Sulfate group = Detoxification of phenolic drugs ROS = Generation associated with cell damage</p> Signup and view all the answers

    What percentage of single nucleotide polymorphisms (SNPs) significantly impact protein function?

    <p>1%</p> Signup and view all the answers

    Genetic variability has no effect on drug metabolism.

    <p>False</p> Signup and view all the answers

    What is the primary use of Warfarin in medicine?

    <p>Anticoagulant</p> Signup and view all the answers

    Patients with CYP2C92 and CYP2C93 allelic variants are considered to be ________ metabolisers.

    <p>poor</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Pharmacodynamics = Study of the effects and mechanisms of drug action Pharmacokinetics = Study of how drugs are absorbed, distributed, metabolized, and excreted Pharmacogenomics = Study of how genes affect an individual's response to drugs NSAIDs = Nonsteroidal anti-inflammatory drugs used to reduce inflammation and pain</p> Signup and view all the answers

    Which drug administration route provides the fastest absorption?

    <p>Intravenous (IV)</p> Signup and view all the answers

    The bioavailability of a drug is the fraction of administered drug that reaches the blood plasma.

    <p>True</p> Signup and view all the answers

    What is the main site of xenobiotic metabolism in the body?

    <p>Liver</p> Signup and view all the answers

    Drug absorption through the lungs is termed __________.

    <p>inhaled</p> Signup and view all the answers

    Match the following drug administration routes with their corresponding characteristics:

    <p>Intravenous (IV) = Fastest absorption Oral = First-pass metabolism Topical = Through the skin Rectal = Suppository form</p> Signup and view all the answers

    What effect does the first-pass metabolism have on drugs when administered orally?

    <p>Decreases drug concentration before reaching circulation</p> Signup and view all the answers

    Phase I transformations in xenobiotic metabolism increase the water solubility of compounds.

    <p>True</p> Signup and view all the answers

    What is the term for drugs that need to be metabolized to become active?

    <p>Pro-drugs</p> Signup and view all the answers

    What is the primary role of alcohol dehydrogenase in metabolism?

    <p>It converts alcohol into acetaldehyde.</p> Signup and view all the answers

    The therapeutic index measures the safety of a drug by comparing the dose that is effective for 50% of subjects to the dose that is toxic for all subjects.

    <p>False</p> Signup and view all the answers

    What is the effect of liver CYP activity on drugs?

    <p>It generates acetaldehyde and reactive oxygen free radicals.</p> Signup and view all the answers

    The excretion of drugs through the kidneys involves passing through the __________ filter.

    <p>glomerular</p> Signup and view all the answers

    What is the primary function of the therapeutic index?

    <p>To measure the safety of a drug.</p> Signup and view all the answers

    Drugs with a molecular weight greater than 60,000 are typically reabsorbed in the kidneys.

    <p>True</p> Signup and view all the answers

    What harmful products can be generated by the interaction of free radicals with lipids?

    <p>Reactive molecules, including adducts.</p> Signup and view all the answers

    What type of drug receptor interaction prevents the effect of endogenous agonists?

    <p>Antagonists</p> Signup and view all the answers

    Agonists only have affinity for receptors and do not generate a biological response.

    <p>False</p> Signup and view all the answers

    What is the term for the measure of ability of binding to generate an effect?

    <p>Intrinsic activity</p> Signup and view all the answers

    The ______ constant, Kd, indicates the tendency of a drug to bind to its receptor.

    <p>dissociation</p> Signup and view all the answers

    What characterizes all drug targets?

    <p>They are primarily proteins.</p> Signup and view all the answers

    Hydrophobicity, hydrogen bonds, and ionic bonds are all factors governing drug action.

    <p>True</p> Signup and view all the answers

    What is meant by 'ED50' in pharmacodynamics?

    <p>The dose required to achieve 50% of the maximum effect.</p> Signup and view all the answers

    Drugs with high potency can also be highly ______.

    <p>toxic</p> Signup and view all the answers

    Which type of bond is NOT typically involved in the affinity of binding?

    <p>Magnetic bonds</p> Signup and view all the answers

    Which of the following is the most important isoenzyme for drug metabolism in humans?

    <p>CYP3A4</p> Signup and view all the answers

    Cytochrome P450 enzymes are only found in the liver.

    <p>False</p> Signup and view all the answers

    What is the chief phase I reaction carried out by cytochrome P450 enzymes?

    <p>Hydroxylation</p> Signup and view all the answers

    CYP enzymes can be affected by genetic ______ which leads to variations in drug metabolism.

    <p>polymorphisms</p> Signup and view all the answers

    Match the following factors with their respective effects on drug metabolism:

    <p>Age = Babies and older adults require lower drug doses Sex = Differences in metabolism rates Disease = Hepatic disease affects enzyme activity Diet = Nutrition can influence drug metabolism</p> Signup and view all the answers

    Which of the following actions can be taken by inducers of CYP enzymes?

    <p>Accelerate metabolism</p> Signup and view all the answers

    Advanced age has less effect on CYP450 enzyme activity compared to other metabolic pathways.

    <p>False</p> Signup and view all the answers

    What is the role of NADPH-P450 reductase in drug metabolism?

    <p>It provides reducing equivalents necessary for the mono-oxygenation reaction.</p> Signup and view all the answers

    The ______ of drugs by CYP enzymes can lead to adverse reactions, especially in patients with narrow therapeutic ranges.

    <p>metabolism</p> Signup and view all the answers

    Severe drug interactions from CYP activity can result from which of the following?

    <p>Competition for the same isoenzyme</p> Signup and view all the answers

    Study Notes

    Introduction to Pharmacology

    • Pharmacology is the study of medications (chemical compounds) interacting with living systems to produce a certain effect.
    • It involves understanding how molecules interact with cells, tissues, and organisms.

    Learning Outcomes

    • Review basic pharmacology principles.
    • Describe pharmacodynamics, pharmacokinetics, and pharmacogenomics of drugs.
    • Explain drug discovery and development.
    • Review a drug class (e.g., NSAIDs) regarding discovery, development, uses, and potential toxicity.

    Session Outline

    • Definition of pharmacology.
    • Pharmacodynamics.
    • Pharmacokinetics.
    • Pharmacogenomics and personalized medicine.
    • Drug discovery.
    • Case study: NSAIDs (Nonsteroidal Anti-inflammatory Drugs).

    Definitions

    • Drugs are chemicals interacting with molecules in living systems.
    • Exogenous drugs mimic original molecules.
    • Endogenous drugs replace original molecules.
    • Pharmacy is the preparation, dispensing, or developing and synthesizing of drugs.
    • Pharmacology is the study of how drugs interact with living systems.

    Domains of Pharmacology

    • Pharmacotherapy: Application of drugs in prevention, treatment, or diagnosis of diseases.
    • Pharmacodynamics: Drug's action on the body (pharmacodynamics vs pharmacokinetics). Drug-receptor interaction, dose-response, and mechanisms of action.
    • Pharmacokinetics: Body's action on drugs (absorption, distribution, metabolism, excretion).
    • Toxicology: Study of harmful drug effects.
    • Pharmacogenomics: How genes affect drug efficacy.

    The Nature of Drugs: Size

    • Small molecules (molecular weight <1000 Da) can be given orally, distributing appropriately across body compartments.
    • Biopharmaceuticals (molecular weight >1000 Da) typically given parenterally.

    The Nature of Drugs: Shape

    • Many drugs are stereoisomers (chiral enantiomers), differing in their ability to bind to receptors and other functions (Michaelis-Menten kinetics).

    Drug Names: Brand vs Generic

    • Chemical names are based on molecular structure.
    • Generic names are non-proprietary, assigned by regulatory bodies.
    • Brand names are proprietary, used by pharmaceutical companies.

    Pharmacodynamics

    • Action of drugs on the body.
    • Response to a given concentration of a drug depends on the amount of drug at the site of action. Drug concentration surrounding receptors affects response.
    • Response plateaus at high concentrations.

    Pharmacodynamics (detailed)

    • Drugs act by binding to specific molecules in the body, which can be receptors, enzymes, or transporters. Drugs typically mimic, block, or alter the function of these.
    • Types of Drug-Receptor Interactions:
      • Agonists: Drugs that activate receptors.
      • Antagonists: Drugs that block receptors, preventing agonists from binding.

    Types of Drug-Endogenous interactions

    • Antagonists typically compete with endogenous agonists for the same binding site (reversable).

    Factors governing drug action

    • Affinity: Measure of how tightly a drug binds to its receptor.
    • Intrinsic Activity: Measure of a drug's ability to produce an effect once bound to its receptor. Independent of affinity.
    • Agonists have both affinity and intrinsic activity.
    • Antagonists only have affinity.

    Affinity of binding

    • Binding of a drug (D) to a receptor (R) depends on hydrophobicity, hydrogen bonds, ionic bonds, Van der Waals forces, and covalent bonds.

    Receptor occupancy and affinity

    • Strength of binding determined by Michaelis-Menten enzyme kinetics. More receptor sites are occupied as ligand concentration increases. Dissociation constant (Kd) measure of tendency to bind.

    Intrinsic Activity (Efficacy)

    • Drugs vary in their ability to initiate a response.
    • Intrinsic activity measured after binding to receptors.
    • Used to assess the potency of drugs.

    Log Transformation of MM Curve

    • Intrinsic activity is the maximum effect a drug can produce.
    • ED50 is the dose needed to produce 50% of the maximum effect, indicative of potency.
    • Highly potent drugs can be toxic.

    Competitive Antagonist

    • Shifts dose-response curve to the right.
    • More drug needed to overcome inhibition but maximum effect is still achievable.

    Partial Agonists

    • Activate receptors but do not produce a full response.
    • Lower intrinsic activity than full agonists.

    Pharmacokinetics

    • Study of how the body influences drugs.
    • Absorption: Drug movement from administration site to bloodstream.
    • Distribution: Drug movement from bloodstream to tissues.
    • Metabolism: Drug transformation to facilitate elimination.
    • Excretion: Removal of drugs/metabolites from the body (e.g., kidney, liver, bile).
    • ADMET criteria used to assess drug properties.

    Drug Absorption

    • Orally (orally swallowed): Includes dissolution of solid tablets and the first-pass effect.
    • Mucosal Membranes: Absorption through oral, nasal, topical, or rectal routes.

    Faster Absorption

    • Parenterally (injection): (e.g., intravenous, intramuscular, subcutaneous, intraperitoneal).
    • Inhaled: (e.g., through lungs, via airways).

    Drug Distribution

    • Drug movement from bloodstream to tissues.
    • Hydrophobic compounds may bind to proteins (e.g., in the blood)
    • Effective concentration of drug reduces if distributed widely.
    • Targets like the blood-brain barrier are difficult to target.

    Pharmacokinetics Process

    • Drug movement from administration site to elimination.
    • Drugs are transported throughout the body via blood, lymph, and interstitial fluid.
    • Drugs move across membranes based on lipid solubility. Charged molecules require specialised channels.

    Bioavailability

    • Fraction of administered drug that reaches the bloodstream.
    • AUC is the area under a concentration-time curve and helpful to demonstrate bioavailability.

    Blood Levels Determine Dosage

    • Drug levels in blood (peak, trough, therapeutic window, toxic levels) determine dosage.
    • Therapeutic window represents the range of drug concentrations at which beneficial effects are seen without toxic effects

    Xenobiotic Metabolism

    • Body's defense against foreign compounds (xenobiotics).
    • Altering drug effectiveness, drug must be given more frequently, requiring higher doses.
    • Pro-drugs require metabolism to be active.
    • First-pass metabolism alters drug before full circulation.

    Xenobiotic Metabolism: Liver

    • Liver is the primary site of xenobiotic metabolism.
    • Different routes (e.g., oral, topical, IV) of drug administration result in different influence on liver.

    Phase I and Phase II transformations

    • Phase 1 reactions modify compounds to have greater polarity.
    • Phase 2 reactions conjugate and enhance compounds with added water solubility for excretion.

    CYP450 Enzymes (Phase I)

    • Key role in drug metabolism.
    • Family members (isoenzymes) differ in structure and activity.
    • Important for drug metabolism, including cholesterol. Important for many pathways affecting drugs and other chemicals.

    CYP450 Superfamily

    • Classified by amino acid similarity.
    • CYP isoenzymes are important in human drug metabolism. Different isoenzymes impact drugs in different ways.

    CYP3A4

    • Most significant cytochrome P450 enzyme in drug metabolism in the liver and enterocytes (GI tract).

    Phase I Reaction (Hydroxylation)

    • Key phase 1 reaction for drug metabolism
    • Involves the addition of hydroxyl groups (–OH).
    • Converts lipid-soluble drugs to water-soluble drugs for easy excretion.

    Factors affecting metabolism by CYP450

    • Age plays a significant role.
    • Sex, pathological status, diet, hormones, genetic differences, drug-drug interactions affect drug metabolism.

    Genetic Polymorphisms of CYPs

    • Genetic variations (SNPs) in CYP isoenzymes affect drug metabolism rates.
    • This leads to variability in drug response.
    • Results in differences in metabolism of same drugs between individuals
    • Some have poor metaboliser phenotypes, meaning drugs take longer, resulting in toxicity or reduced efficacy.

    Drug-Drug Interactions

    • Inducers accelerate metabolism, resulting in reduced bioavailability.
    • Inhibitors slow metabolism, increasing the risk of toxicity.

    Drug-Drug interactions: Clinical Considerations

    • Must avoid clinically significant interactions by managing drug administration, frequency, and dosing regimens.
    • This is important to ensure therapeutic success and minimize adverse side effects

    Excretion: Bile

    • Compounds actively transported into bile, to the intestine for excretion.
    • Drugs or metabolites further degraded by digestive enzymes before excretion.
    • Enterohepatic recycling refers to reabsorption of drugs into the bloodstream.

    Excretion: Kidneys

    • Drugs passed through the glomerular filter and excreted in urine.
    • Many metabolites and water are reabsorbed. Drugs not reabsorbed will be excreted.

    Excretion affects half life of drugs

    • Elimination of drugs through various routes affects their half-life, and determines appropriate dosing.

    Therapeutic Index

    • TI = ED50 (effective dose)/TD50 (toxic dose).
    • Comparing effective dose and toxic dose for treatment.
    • Higher value of this index indicates greater safety.

    Therapeutic Index: Examples

    • Warfarin (low TI): Requires tightly controlled dosing for optimal treatment.
    • Penicillin (high TI): Has a wide therapeutic window.

    Personalized Medicine

    • Individualized treatment approaches using genetic information to tailor drug selection and dosages.
    • Important to consider genetic variation before prescribing drugs.

    Warfarin: Case study

    • Anticoagulant used to prevent blood clots.
    • Metabolised by CYP2C9 enzymes, leading to significant variable efficacy, requiring dosing changes dependent on different genetic makeup of individuals. Higher risk of bleeding is observed due to a narrow therapeutic window.

    Further Reading

    • Basic pharmacology textbooks available in the library.
    • Additional reading material available on Canvas and reading lists.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Introduction to Pharmacology 2025 PDF

    Description

    Test your knowledge on drug-drug interactions and the complexities of pharmacogenomics. This quiz covers various aspects, including detoxification processes, metabolism, and the impacts of genetic variability on drug efficacy. Challenge yourself with questions on specific substances, metabolic pathways, and clinical implications in pharmacology.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser