Clinical pharmacokinetics worksheet with answers

Practice exercise (made-up values, not clinical guidance). In a patient, lidocaine has an elimination half-life of 1.5 h. Find the elimination rate constant k in h⁻¹.

Practice exercise (made-up values, not clinical guidance). A patient who weighs 107 kg needs a loading dose of tobramycin to reach a level of 8 mg/L straight away. The volume of distribution is 0.3 L/kg. Find the loading dose LD in mg.

Practice exercise (made-up values, not clinical guidance). A patient receives an IV bolus of 240 mg of gentamicin. The level back-extrapolated to time zero is 10 mg/L and the half-life is 3.5 h. Find the clearance CL in L/h.

Practice exercise (made-up values, not clinical guidance). A patient receives an IV bolus of 190 mg of tobramycin. The level back-extrapolated to time zero is 8 mg/L and the half-life is 2 h. Find the volume of distribution Vd.

Practice exercise (made-up values, not clinical guidance). A 52 kg patient on regular tobramycin doses is at steady state. The target is a peak of 7 mg/L and a trough of 0.5 mg/L, and the volume of distribution is 0.25 L/kg. Assuming rapid IV doses, what dose D raises the level from the trough to the peak?

Practice exercise (made-up values, not clinical guidance). A 63 kg patient has a theophylline level of 7.2 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?