Pharmacokinetics .
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Questions and Answers

Which process is responsible for transporting Vitamin B12 across the gut wall?

  • Exocytosis
  • Active transport
  • Endocytosis (correct)
  • Diffusion
  • What is the main factor affecting drug absorption discussed in the text?

  • Temperature
  • Pressure
  • Light exposure
  • Effect of pH (correct)
  • Why do weak acids pass through membranes more readily?

  • Because the protonated form penetrates through membranes
  • Because the uncharged, protonated form can permeate through membranes (correct)
  • Because they are charged
  • Because they are positively charged
  • What determines the distribution of a drug between its ionized and unionized forms?

    <p>pKa and ambient pH of the drug</p> Signup and view all the answers

    What is the most common and safest route of drug administration?

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

    Why are oral drugs easily self-administered?

    <p>They can be swallowed</p> Signup and view all the answers

    What complicates the pathways involved in oral drug absorption?

    <p>Low gastric pH</p> Signup and view all the answers

    Why is activated charcoal used in cases of oral drug overdose?

    <p>To prevent drug absorption</p> Signup and view all the answers

    What does Volume of Distribution (Vd) compare the distribution of a drug with?

    <p>Volumes of the water compartments in the body</p> Signup and view all the answers

    Which compartment has a low Volume of Distribution similar to plasma volume?

    <p>Plasma compartment</p> Signup and view all the answers

    What is bioavailability?

    <p>The percentage of a drug that reaches the systemic circulation after a specific route of administration</p> Signup and view all the answers

    In which compartment would a hydrophilic drug with low molecular weight distribute more readily?

    <p>Extracellular fluid</p> Signup and view all the answers

    Why does orally administered drugs often undergo first-pass metabolism?

    <p>Because the liver metabolizes the drug before it reaches the systemic circulation</p> Signup and view all the answers

    What is the formula for calculating Volume of Distribution (Vd)?

    <p>Vd = Dose / C0</p> Signup and view all the answers

    What does the area under the curve (AUC) measure in pharmacokinetics?

    <p>Total drug exposure over time after administration</p> Signup and view all the answers

    How does first-pass hepatic metabolism affect bioavailability?

    <p>Decreases the amount of unchanged drug reaching the systemic circulation</p> Signup and view all the answers

    Volume of Distribution (Vd) has a physiologic or physical basis.

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

    A drug with high molecular weight or extensive protein binding would have a low Volume of Distribution (Vd).

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

    Heparin shows characteristics of distribution similar to Extracellular Fluid.

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

    A hydrophilic drug with a low molecular weight can easily distribute into the interstitial fluid.

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

    Metabolism leads to production of products with decreased polarity.

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

    Most drugs are eliminated according to zero-order kinetics.

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

    Drug clearance estimates the amount of drug cleared from the body per unit of volume.

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

    Kidneys can efficiently eliminate lipophilic drugs that are reabsorbed in the distal convoluted tubules.

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

    Drug excretion may occur via sweat, saliva, tears, hair, and skin to a large extent.

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

    Total body clearance and drug half-life are not important measures of drug clearance.

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

    The liver does not contribute to drug clearance through metabolism or excretion into the bile.

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

    The kidney is not a major organ of excretion in drug clearance.

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

    Patients with diminished renal or hepatic blood flow may experience a decrease in drug half-life.

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

    Increased hepatic blood flow can lead to a decrease in the half-life of a drug.

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

    Patients with decreased ability to extract drug from plasma may require an increase in drug dosage.

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

    Which process is NOT involved in the elimination of drugs through the kidneys into urine?

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

    What is the normal glomerular filtration rate (GFR) approximately in mL/min?

    <p>125</p> Signup and view all the answers

    Which factor does NOT influence the passage of drugs into the glomerular filtrate during glomerular filtration?

    <p>Molecular weight</p> Signup and view all the answers

    Where do drugs that were not transferred into the glomerular filtrate leave the glomeruli to enter the proximal tubule?

    <p>Efferent arterioles</p> Signup and view all the answers

    Why is intravenous (IV) injection considered the most common parenteral route of drug administration?

    <p>It allows for rapid drug delivery to the systemic circulation.</p> Signup and view all the answers

    What distinguishes depot preparations used in intramuscular (IM) drug administration from aqueous solutions?

    <p>They are usually suspended in a nonaqueous vehicle.</p> Signup and view all the answers

    Which factor contributes to the higher peak plasma concentrations seen when drugs are administered as an IV bolus compared to IV infusion?

    <p>Immediate full delivery to the systemic circulation</p> Signup and view all the answers

    What is a disadvantage associated with the intradermal route of drug administration?

    <p>High potential for pain and fear</p> Signup and view all the answers

    Which organ is primarily involved in the elimination of anesthetic gases?

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

    Excretion of most drugs into which of the following occurs only to a small extent?

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

    Total body clearance is the sum of clearances from which drug-processing and drug-eliminating organs?

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

    What is a potential source of undesirable side effects to a breast-feeding infant regarding drug clearance through metabolism?

    <p>Medications taken by the mother</p> Signup and view all the answers

    What is the primary location where secretion of drugs occurs in the kidneys?

    <p>Proximal tubules</p> Signup and view all the answers

    How does manipulating urine pH help increase drug clearance in the kidneys?

    <p>By increasing the fraction of ionized drug in the lumen</p> Signup and view all the answers

    Which process is responsible for increasing the elimination of weak bases from the body?

    <p>Acidification of the urine</p> Signup and view all the answers

    What can be done to decrease the reabsorption of weak acids in a patient presenting with an overdose?

    <p>Alkalinization of the urine</p> Signup and view all the answers

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