Pharmacokinetics and Biopharmaceutics Flashcards
7 cards from real KAPS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pharmacokinetics and Biopharmaceutics flashcards as text
Which route of administration MOST effectively avoids first-pass hepatic metabolism?
Answer: Sublingual tablet
Sublingual administration allows drugs to be absorbed directly through the oral mucosa into systemic circulation, completely bypassing the GI tract and hepatic first-pass effect.
Why is the protein binding of a drug clinically significant?
Answer: Only the free (unbound) drug fraction is pharmacologically active and available for distribution
Only free (unbound) drug can cross membranes, interact with receptors, be metabolized, and be excreted; protein-bound drug acts as an inactive reservoir.
Which formulation strategy would MOST effectively increase the oral bioavailability of a poorly water-soluble drug (BCS Class II)?
Answer: Micronization to reduce particle size
Micronization increases the surface area of drug particles, which enhances dissolution rate and thereby improves oral bioavailability for poorly soluble drugs.
Enterohepatic recirculation refers to:
Answer: Drug cycling between the intestine and liver via biliary excretion followed by intestinal reabsorption
Enterohepatic recirculation occurs when drug or its metabolites excreted into bile are reabsorbed from the intestine, prolonging the drug's half-life and duration of action.
The Henderson-Hasselbalch equation is MOST useful in pharmacokinetics for predicting:
Answer: The degree of ionization of a drug at a given pH
The Henderson-Hasselbalch equation (pH = pKa + log[A⁻]/[HA]) predicts the ionization state of a drug at any given pH, which directly governs membrane permeability and absorption.
Which statement about zero-order elimination kinetics is CORRECT?
Answer: A fixed absolute amount of drug is eliminated per unit time
In zero-order kinetics, a constant amount (not fraction) of drug is eliminated per unit time because the elimination pathway is saturated, as seen with ethanol and phenytoin at high doses.
A patient with severe renal impairment is prescribed a drug that is 90% renally eliminated unchanged. What is the MOST appropriate dosing adjustment?
Answer: Reduce the dose or extend the dosing interval to prevent toxicity
Renal impairment reduces clearance of renally eliminated drugs, causing drug accumulation; the dose should be reduced and/or the interval extended to prevent toxic plasma concentrations.