Pharmacokinetics Flashcards
7 cards from real Pharmacy 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 flashcards as text
Which plasma protein is the primary binding protein for most acidic drugs?
Answer: Albumin
Albumin is the predominant plasma protein for binding acidic drugs (e.g., warfarin, NSAIDs), while alpha-1-acid glycoprotein primarily binds basic drugs.
A patient with severe hypoalbuminemia is receiving a drug that is 95% protein-bound. What effect would you expect?
Answer: Increased free drug concentration and potential toxicity
With less albumin available for binding, more drug remains unbound (free), increasing the pharmacologically active fraction and the risk of toxicity.
Which of the following best describes zero-order pharmacokinetics?
Answer: Drug concentration decreases by a fixed amount per unit time and half-life increases with dose
Zero-order kinetics occur when elimination capacity is saturated; a constant amount (not percentage) of drug is eliminated per unit time, so half-life is not constant and increases with higher doses.
Creatinine clearance (CrCl) is most commonly used clinically to estimate:
Answer: Renal function for drug dosing adjustments
CrCl is the standard marker for glomerular filtration rate (GFR) and is used to estimate renal function to guide dose adjustments for renally eliminated drugs.
The Cockcroft-Gault equation is used in pharmacy practice to estimate:
Answer: Creatinine clearance (CrCl) as a surrogate for GFR
The Cockcroft-Gault equation estimates CrCl using serum creatinine, age, weight, and sex, and is the standard method for renal dose adjustment calculations.
A drug follows first-order kinetics with a half-life of 6 hours. After 18 hours, approximately what percentage of the original dose remains?
Answer: 12.5%
After 3 half-lives (18 hours = 3 × 6h), 50% → 25% → 12.5% remains; each half-life reduces the remaining drug by 50%.
Steady-state plasma concentration during continuous dosing is typically reached after approximately:
Answer: 3–5 half-lives
Steady state is reached when the rate of drug input equals the rate of elimination, which occurs after approximately 3–5 half-lives regardless of dose or dosing interval.