Clinical pharmacokinetics worksheet with answers

Practice exercise (made-up values, not clinical guidance). A patient starts regular doses of gentamicin, which has a half-life of 2.5 h. Using the rule that steady state is reached after about five half-lives, after how many hours t_ss is steady state reached?

Practice exercise (made-up values, not clinical guidance). A patient who weighs 67 kg needs a loading dose of vancomycin to reach a level of 20 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). Vancomycin is given as a continuous infusion to a patient whose vancomycin clearance is 85 mL/min. What infusion rate R in mg/h gives a steady-state level of 25 mg/L?

Practice exercise (made-up values, not clinical guidance). A 75 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 96 kg patient takes oral theophylline (F = 1) every 12 h. The clearance is 0.045 L/kg/h. Each dose is 500 mg of theophylline. Find the average steady-state level C_ss,avg.

Practice exercise (made-up values, not clinical guidance). A 64 kg patient has a theophylline level of 3.6 mg/L; the target is 12 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?