Clinical pharmacokinetics worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient who weighs 89 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 who weighs 72 kg needs a loading dose of theophylline to reach a level of 15 mg/L straight away. The volume of distribution is 0.5 L/kg. Find the loading dose LD in mg.

Practice exercise (made-up values, not clinical guidance). A 54 kg patient is to be loaded intravenously with phenytoin sodium to reach a phenytoin level of 20 mg/L. The volume of distribution is 0.7 L/kg and the salt factor is S = 0.92. Find the loading dose LD of phenytoin sodium in mg.

Practice exercise (made-up values, not clinical guidance). A 79 kg patient is to be loaded intravenously with aminophylline to reach a theophylline level of 12 mg/L. The volume of distribution is 0.5 L/kg and the salt factor is S = 0.8. Find the loading dose LD of aminophylline in mg.

Practice exercise (made-up values, not clinical guidance). A patient's gentamicin half-life is 2 h. The target is a peak of 7 mg/L and a trough of 0.5 mg/L. Assuming rapid IV doses and first-order elimination, what dosing interval τ lets the level fall from the peak to the trough? Round to one decimal place.

Practice exercise (made-up values, not clinical guidance). A 73-year-old man weighs 80 kg and has a serum creatinine of 2.2 mg/dL (194 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 tobramycin regimen is 120 mg every 8 h for a creatinine clearance of 120 mL/min. Keeping the dose, the interval is lengthened in proportion to the fall in clearance. Find the new dosing interval τ. Round to one decimal place.