Pharmacology for EMS - Week 4 Lecture 1
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Questions and Answers

What does pharmacokinetics primarily examine?

  • The psychological effects of drugs
  • How drugs are manufactured
  • The history of drug development
  • What the body does to the drug (correct)

    • Which of the following is NOT a component of pharmacokinetics?

  • Absorption
  • Metabolism
  • Traumatic intervention (correct)
  • Excretion

    • What is absorption in the context of pharmacokinetics?

  • The breakdown of drug in the liver
  • The distribution of drug throughout body tissues
  • The administration of a drug
  • The process by which unchanged drug proceeds from the site of administration to the blood (correct)

    • Which phase of pharmacokinetics is primarily responsible for altering drug concentration in the body?

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

    Which factor does pharmacokinetics determine?

    <p>Duration of action</p> Signup and view all the answers

    What is bioavailability in pharmacology?

    <p>The extent and rate at which the active ingredient is absorbed and becomes available at the site of action</p> Signup and view all the answers

    What does the route of drug administration affect?

    <p>Bioavailability, onset of action, peak plasma concentration, and duration of action</p> Signup and view all the answers

    What organ is primarily involved in the metabolism of drugs?

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

    What is the main site of absorption for orally ingested drugs?

    <p>Small intestine</p> Signup and view all the answers

    Which factor influences drug absorption by affecting the circulation to the site of administration?

    <p>Blood flow</p> Signup and view all the answers

    What effect does first pass metabolism have on a drug's bioavailability?

    <p>Reduces bioavailability</p> Signup and view all the answers

    Which drug is typically administered by injection rather than orally due to its breakdown?

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

    What is a significant disadvantage of intravenous drug administration?

    <p>Invasive nature</p> Signup and view all the answers

    What is the primary characteristic of intramuscular administration compared to intravenous administration?

    <p>Intramuscular administration results in slower absorption.</p> Signup and view all the answers

    Why might a clinician choose a topical administration route over systemic absorption?

    <p>For a localized effect</p> Signup and view all the answers

    Which type of drugs are readily absorbed through unbroken skin?

    <p>Lipid-soluble compounds</p> Signup and view all the answers

    What is distribution in the context of pharmacology?

    <p>The transfer of a drug between locations in the body.</p> Signup and view all the answers

    What characteristic of a drug enhances its absorption across membranes?

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

    Which method results in the fastest drug administration?

    <p>Intravenous injection</p> Signup and view all the answers

    Which factor significantly affects the rate of drug absorption after intramuscular administration?

    <p>Local blood flow to the administration site</p> Signup and view all the answers

    Which characteristic of the blood-brain barrier affects drug permeation?

    <p>It prevents drugs unless they are lipid soluble.</p> Signup and view all the answers

    What is meant by the half-life of a drug?

    <p>The time taken for the drug's plasma concentration to fall by one-half.</p> Signup and view all the answers

    How does drug elimination primarily occur?

    <p>By metabolism in the liver and excretion.</p> Signup and view all the answers

    What determines the rate of termination of a drug's physiological response?

    <p>The amount of drug that is metabolized and excreted.</p> Signup and view all the answers

    What best describes drug metabolism?

    <p>The processes of chemical modification of a drug.</p> Signup and view all the answers

    Which organ is primarily responsible for drug metabolism?

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

    How does drug solubility affect excretion?

    <p>Only water-soluble drugs can be eliminated by the kidneys.</p> Signup and view all the answers

    What role do cytochrome P450 enzymes play in drug metabolism?

    <p>They modify drugs into metabolites.</p> Signup and view all the answers

    Which statement about drug excretion is accurate?

    <p>Drug excretion can occur through sweat or expired air.</p> Signup and view all the answers

    What is a significant effect of reduced renal function on drug elimination?

    <p>It can slow down the rate of drug excretion.</p> Signup and view all the answers

    Which of the following is NOT a route of drug excretion?

    <p>Tissue absorption</p> Signup and view all the answers

    What is the result of drug metabolism?

    <p>The production of less active or inactive metabolites.</p> Signup and view all the answers

    Study Notes

    Pharmacology for EMS - Week 4 Lecture 1: Principles of Pharmacology (ii)

    • This lecture covers the principles of pharmacokinetics, common variables affecting drug absorption and distribution, the concept of drug bioavailability, and different drug administration routes and their effects.

    Pharmacokinetics

    • Pharmacokinetics is defined as "what the body does to the drug."
    • It examines how a drug is altered during absorption, distribution, metabolism, and excretion.
    • Pharmacokinetics involves absorption, distribution, metabolism, and excretion.

    Drug Bioavailability

    • The concept of drug bioavailability is described in week 4.
    • Bioavailability refers to the proportion of an administered drug that reaches the systemic circulation.

    Drug Administration Routes

    • Different administration routes affect bioavailability, onset of action, peak plasma concentration, and duration of action.
    • The lecture details various routes, comparing their effects on these pharmacokinetic parameters.
    • The speed and effectiveness of different administration routes are discussed.
    • Examples include intravenous, intramuscular, oral, and topical routes.

    Variables Affecting Drug Absorption and Distribution

    • Common variables affecting drug absorption and distribution are outlined.
    • Factors impacting absorption and distribution are explained.
    • The lecture notes discuss elements like the absorbing surface area, blood flow, drug solubility, ionization, and formulation.

    Absorption

    • Absorption is the process of an unchanged drug moving from the site of administration to the bloodstream.
    • It's crucial for most drug administration methods (except IV).
    • The route of drug administration impacts absorption.
    • The factors that influence absorption are the nature of the absorbing surface, blood flow, drug solubility, ionization, and formulation of the drug.

    Distribution

    • Distribution is the reversible transfer of a drug between locations within the body.
    • Drugs initially are primarily distributed to organs with good blood supply and slower to those with less.
    • The presence of free drugs and drug-protein complexes, as well as lipid solubility, contribute to the distribution of a drug.

    First Pass Metabolism

    • The liver is the primary site of drug metabolism.
    • Often, a significant portion of the absorbed drug undergoes metabolism before reaching the systemic circulation.
    • First-pass metabolism reduces bioavailability.
    • Factors influencing first pass metabolism are explored.

    Elimination (Metabolism and Excretion)

    • Elimination is the irreversible removal of a drug from the body through metabolism and excretion.
    • Drugs are primarily metabolized by liver enzymes.
    • Metabolites are often less active than the parent drug.
    • Elimination routes, including urine, feces, sweat, expired air, and breast milk are mentioned.

    Renal Clearance

    • Kidneys are the major route for eliminating water-soluble drugs.
    • Lipid-soluble drugs are poorly excreted by the kidneys.
    • Reduced renal function affects excretion and elimination rates.

    Topical Administration

    • Topical administration primarily aims for localized effects.
    • Lipid-soluble drugs are more easily absorbed through the skin.
    • Transdermal patches are used for steady-state delivery.

    Intravenous, Intramuscular Routes

    • Intravenous administration is rapid, but invasive, while intramuscular is less invasive but slower-acting.
    • Slower intramuscular absorption can result in safer plasma concentrations than intravenous.
    • Local blood supply influences absorption rates for intramuscular injections.

    Blood-Brain Barrier (BBB)

    • The BBB prevents many drugs from crossing.
    • Increased lipid solubility of drugs improves their ability to cross the BBB
    • Certain conditions, e.g. inflammation, can affect the integrity of the BBB, allowing greater drug penetration.

    Rate of Elimination

    • The half-life of a drug is the timeframe for plasma concentration to decrease by 50%.
    • Half-life is impacted by distribution volume and clearance rate.
    • Dosing frequency considerations include half-life to avoid large fluctuations in plasma concentration.

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    Related Documents

    EHS 202 Pharmacology for EMS Week 4 Lecture 1 PDF

    Description

    Explore the foundations of pharmacokinetics in this lecture, focusing on drug absorption, distribution, metabolism, and excretion. Understand the concept of drug bioavailability and discover the various routes of drug administration and their effects on treatment outcomes.

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