NURS 1060: Drug Absorption Concepts Exam 1
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Questions and Answers

What is the process that occurs before a drug can be absorbed in the GI tract?

  • Distribution
  • Disintegration (correct)
  • Metabolism
  • Excretion
  • Which route of drug administration is considered parenteral?

  • Sublingual
  • Rectal
  • Oral
  • IV (correct)
  • What is the primary mechanism by which most drugs are absorbed into the bloodstream?

  • Passive Diffusion (correct)
  • Active Transport
  • Endocytosis
  • Facilitated Diffusion
  • What type of molecules can generally cross a lipid membrane?

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

    How does ionization affect a drug's solubility in relation to the environment's pH?

    <p>It causes acids to become charged particles.</p> Signup and view all the answers

    What are the four basic pharmacokinetic processes in sequence?

    <p>Absorption, Distribution, Metabolism, Excretion</p> Signup and view all the answers

    How does the blood-brain barrier affect drug absorption?

    <p>It selectively allows certain drugs to cross into the brain.</p> Signup and view all the answers

    What is the role of P-Glycoprotein in drug absorption?

    <p>It serves as a transporter that can limit drug absorption.</p> Signup and view all the answers

    What is the primary difference between enteral and parenteral routes of administration?

    <p>Parenteral bypasses the digestive system.</p> Signup and view all the answers

    What is meant by the term 'metabolism' in pharmacokinetics?

    <p>The enzymatic breakdown of drugs into metabolites.</p> Signup and view all the answers

    Which process follows drug absorption in pharmacokinetics?

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

    What is the primary characteristic of an acid in relation to protons?

    <p>It acts as a proton donor.</p> Signup and view all the answers

    Why is understanding acid-base balance important in pharmacokinetics?

    <p>It affects the solubility of drugs in the body.</p> Signup and view all the answers

    How does a basic drug behave in an acidic environment?

    <p>It becomes ionized and water soluble.</p> Signup and view all the answers

    What factor significantly contributes to drug absorption in the intestine compared to the stomach?

    <p>More surface area due to villi.</p> Signup and view all the answers

    Which route of drug administration is typically absorbed the fastest?

    <p>Intravenous route.</p> Signup and view all the answers

    Which method is most commonly used by drug developers to ensure a drug crosses cell membranes effectively?

    <p>Direct diffusion across the membrane.</p> Signup and view all the answers

    What type of drugs can most easily cross cell membranes?

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

    In which organ does P-glycoprotein transport drugs out of blood into the urine?

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

    What is the principle of ion trapping based on?

    <p>The pH difference across membranes</p> Signup and view all the answers

    What happens to aspirin when it is in the acidic environment of the stomach?

    <p>It remains non-ionized and easily crosses membranes</p> Signup and view all the answers

    Which of the following accurately describes P-glycoprotein's role?

    <p>It prevents drug absorption</p> Signup and view all the answers

    What type of environment would basic drugs accumulate in during ion trapping?

    <p>Acidic environments</p> Signup and view all the answers

    Which ionized state would aspirin be in a basic environment?

    <p>Fully ionized</p> Signup and view all the answers

    What role do transport systems play in drug movement across cell membranes?

    <p>They actively move drugs against concentration gradients</p> Signup and view all the answers

    How does an acidic pill taken orally dissolve in the stomach?

    <p>It dissolves as non-ionized due to the acidic pH and is lipid soluble.</p> Signup and view all the answers

    What is the pH range of the small intestine where basic pills are absorbed?

    <p>6-7</p> Signup and view all the answers

    Why do basic pills remain in the stomach when taken orally?

    <p>They remain ionized due to the acidic pH of the stomach.</p> Signup and view all the answers

    What characterizes drugs that can cross the blood-brain barrier (BBB)?

    <p>They must be able to pass through cell walls and are mostly lipid-soluble.</p> Signup and view all the answers

    What happens to the drug after it is absorbed from the GI tract?

    <p>It travels to the liver before entering general circulation.</p> Signup and view all the answers

    What impact does the rate of absorption have on the effects of a drug?

    <p>It determines both how soon and how intense the effects will be.</p> Signup and view all the answers

    What is the primary method by which drugs cross membranes during absorption?

    <p>Passive Diffusion</p> Signup and view all the answers

    What property of lipid-soluble drugs enhances their ability to penetrate the blood-brain barrier?

    <p>Increased lipophilicity</p> Signup and view all the answers

    What is the primary mechanism by which lipid-soluble drugs enter the brain through the blood-brain barrier?

    <p>Passive diffusion</p> Signup and view all the answers

    Which of the following factors does NOT affect the permeability of drugs across the blood-brain barrier?

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

    Which type of drug is least likely to penetrate the blood-brain barrier effectively?

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

    Which transport mechanism allows the uptake of larger lipid-soluble compounds into cells?

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

    What type of lipid-soluble drugs are more likely to have increased bioavailability in the central nervous system?

    <p>Drugs that are non-ionized</p> Signup and view all the answers

    Which pathological condition is known to alter the permeability of the blood-brain barrier?

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

    What characteristic do lipophilic drugs generally possess?

    <p>Lower polarity</p> Signup and view all the answers

    Study Notes

    Absorption of Drugs

    • Critical thinking and clinical reasoning are essential for accurate and safe medication administration.
    • Clinical Decision Making involves analyzing patient problems to prioritize responses, minimizing adverse changes in patient conditions.

    Pharmacokinetics Overview

    • Pharmacokinetics studies drug movement through four main processes:
      • Absorption: Drug moves from administration site into the bloodstream.
      • Distribution: Drug travels from blood to action or storage sites.
      • Metabolism: Drug undergoes enzymatic breakdown into metabolites.
      • Excretion: Removal of drug or metabolites from the body.

    Drug Administration Routes

    • Enteral: Absorption occurs in the gastrointestinal (GI) tract (e.g., oral, sublingual, rectal).
    • Parenteral: More direct methods bypassing the GI tract (e.g., intravenous (IV), intramuscular (IM), subcutaneous (SubQ)).

    Drug Absorption Process

    • Oral drug absorption requires disintegration (tablet breaking apart) and dissolution (mixing with stomach fluids).
    • Most drugs utilize passive diffusion for absorption, moving from high to low concentration areas.

    Factors Influencing Drug Absorption

    • Rate of dissolution varies by drug.
    • Surface area: Larger surface area in the intestine facilitates faster absorption compared to the stomach.
    • Blood flow: Higher blood flow areas enable more rapid absorption.

    Drug Passage Mechanisms

    • Drugs can cross membranes via:
      • Direct diffusion: Requires lipid solubility.
      • Channels and pores: Very few drugs can use this method.
      • Transport systems: Includes P-glycoprotein, which transports drugs out of cells, limiting absorption.

    Role of P-Glycoprotein

    • Acts as an anti-absorption transporter in organs such as:
      • Liver: Transports drugs into bile for elimination.
      • Kidney: Moves drugs into urine.
      • Intestine: Transfers drugs from blood into intestinal lumen.
      • Brain: Limits drug access to the brain.

    Ionization and Drug Solubility

    • The ionization state of drugs affects their solubility:
      • Acidic drugs tend to ionize in basic (alkaline) environments while basic drugs ionize in acidic environments.
      • Non-ionized forms are lipid-soluble and can diffuse across membranes.

    Ion Trapping (pH Partitioning)

    • Accumulation of drugs occurs based on pH differing across membranes:
      • Acid drugs accumulate in basic environments and vice versa.
    • Example:
      • Aspirin (acid) in the stomach (pH 1) is non-ionized and lipid-soluble, allowing absorption into the bloodstream.

    Blood-Brain Barrier Considerations

    • Tight junctions in CNS capillaries restrict drug passage; only lipid-soluble drugs can penetrate.

    Summary of Absorption Mechanism

    • Oral absorption involves drug movement from the GI tract into the bloodstream, passing through the liver before entering systemic circulation.
    • Overall absorption rate affects drug onset and intensity of effects.

    Lipid-solubility in Pharmacology

    • Lipid-solubility signifies a drug's capability to dissolve in fats, influencing its ability to traverse cell membranes.
    • Drugs with high lipid-solubility are more proficient at penetrating the Blood Brain Barrier (BBB), which safeguards the brain from harmful substances.
    • Increased lipid solubility generally leads to enhanced bioavailability within the central nervous system (CNS).
    • Lipophilic drugs usually possess lower molecular weight and exhibit non-polar characteristics.
    • Notable examples of lipid-soluble drugs include anesthetics, certain antidepressants, and antipsychotics.

    Drug Permeability Mechanisms

    • Diffusion: Lipid-soluble drugs primarily enter the brain through passive diffusion, thanks to their affinity for lipid bilayers.
    • Transport Mechanisms:
      • Carrier-mediated transport: Certain lipid-soluble substances utilize specific transport proteins for crossing the BBB, often through facilitated diffusion.
      • Endocytosis: This process involves cell membrane engulfment, allowing larger lipid-soluble compounds to be taken up.
    • Factors Affecting Permeability:
      • Molecular Size: Smaller molecules find it easier to traverse the BBB.
      • Ionization: Non-ionized (neutral) drug forms have a higher likelihood of penetrating the BBB.
      • Physicochemical Properties: Factors such as lipophilicity, solubility, and charge significantly affect a drug's BBB crossing ability.
    • Pathological Conditions: Conditions like inflammation or injury can modify BBB permeability, permitting more drugs and potentially harmful elements to reach the CNS.
    • Examples:
      • Lipid-soluble drugs such as diazepam, morphine, and propranolol demonstrate effective penetration into the CNS.
      • Conversely, water-soluble drugs like aminoglycosides and penicillin generally struggle to access the brain.
    • Recognizing the relationship between lipid solubility and drug permeability mechanisms is vital in drug design aimed at CNS therapeutic applications.

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    Description

    Test your understanding of drug absorption and the critical thinking necessary for safe medication administration in nursing. This quiz focuses on clinical decision-making processes essential for providing quality patient care and clinical judgment.

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