Clinical pharmacokinetics worksheet with answers

Practice exercise (made-up values, not clinical guidance). Just after an IV dose, the gentamicin level is 6 mg/L. The half-life is 2 h, and the drug is eliminated by first-order kinetics. What is the level C 5.5 h later?

Practice exercise (made-up values, not clinical guidance). A patient receives lidocaine as a constant IV infusion without a loading dose. The half-life is 1.5 h. What percentage f of the steady-state level has been reached after 1.5 h?

Practice exercise (made-up values, not clinical guidance). A 76 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 patient has a lidocaine clearance of 850 mL/min. What infusion rate R in mg/min keeps the steady-state level at 2.5 mg/L?

Practice exercise (made-up values, not clinical guidance). A patient's tobramycin half-life is 4 h. The target is a peak of 8 mg/L and a trough of 1 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 kg patient takes oral theophylline (F = 1) every 12 h. The clearance is 0.05 L/kg/h. What dose D in mg gives an average steady-state level of 10 mg/L?