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). Just after an IV dose, the gentamicin level is 8 mg/L. The half-life is 3.5 h, and the drug is eliminated by first-order kinetics. What is the level C 10.5 h later?

Practice exercise (made-up values, not clinical guidance). A patient receives an IV bolus of 190 mg of gentamicin. The level back-extrapolated to time zero is 8 mg/L and the half-life is 3 h. Find the clearance CL in L/h.

Practice exercise (made-up values, not clinical guidance). A 50 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 98 kg patient has a phenytoin level of 9 mg/L; the target is 15 mg/L. The drug is given intravenously as phenytoin sodium (S = 0.92), and the volume of distribution is 0.7 L/kg. What extra loading dose LD raises the level to the target?

Practice exercise (made-up values, not clinical guidance). A patient receives vancomycin IV every 12 h; the vancomycin clearance is 3.5 L/h. What dose D in mg gives an average steady-state level of 20 mg/L?