Clinical pharmacokinetics worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient who weighs 54 kg needs a loading dose of gentamicin to reach a level of 8 mg/L straight away. The volume of distribution is 0.25 L/kg. Find the loading dose LD in mg.

Practice exercise (made-up values, not clinical guidance). A patient who weighs 50 kg needs a loading dose of vancomycin to reach a level of 25 mg/L straight away. The volume of distribution is 0.7 L/kg. Find the loading dose LD in mg.

Practice exercise (made-up values, not clinical guidance). A patient has a lidocaine clearance of 800 mL/min. What infusion rate R in mg/min keeps the steady-state level at 4 mg/L?

Practice exercise (made-up values, not clinical guidance). A 100 kg patient is to be loaded with digoxin tablets to reach a level of 0.8 mcg/L. The volume of distribution is 7 L/kg and the tablets have a bioavailability F = 0.7. Find the total oral loading dose LD in mcg.

Practice exercise (made-up values, not clinical guidance). A 76 kg patient has a theophylline level of 6 mg/L; the target is 10 mg/L. The drug is given intravenously as aminophylline (S = 0.8), and the volume of distribution is 0.5 L/kg. What extra loading dose LD raises the level to the target?

Practice exercise (made-up values, not clinical guidance). A 51-year-old woman weighs 69 kg and has a serum creatinine of 2.5 mg/dL (221 µmol/L). Estimate the creatinine clearance with Cockcroft–Gault: CrCl (mL/min) = (140 − age) × weight (kg)/(72 × SCr in mg/dL), × 0.85 for women. The usual atenolol dose is 100 mg for a creatinine clearance of 100 mL/min, and a fraction fe = 0.9 of the drug is excreted unchanged by the kidneys. Using the Dettli dose fraction Q = 1 − fe·(1 − CrCl/normal CrCl), find the adjusted dose D. Round to the nearest whole number.