Practice exercise (made-up values, not clinical guidance). A patient starts regular doses of vancomycin, which has a half-life of 10 h. Using the rule that steady state is reached after about five half-lives, after how many hours tss is steady state reached?
Clinical pharmacokinetics worksheet with answers
Practice exercise (made-up values, not clinical guidance). In a patient, tobramycin has an elimination half-life of 3 h. Find the elimination rate constant k in h⁻¹.
Practice exercise (made-up values, not clinical guidance). A patient receives an IV bolus of 220 mg of gentamicin. 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 patient receives an IV bolus of 130 mg of tobramycin. The level back-extrapolated to time zero is 7 mg/L and the half-life is 3 h. Find the volume of distribution Vd.
Practice exercise (made-up values, not clinical guidance). A vancomycin infusion is started without a loading dose. The half-life in this patient is 10 h. How long t does it take to reach 90% of the steady-state level?
Practice exercise (made-up values, not clinical guidance). A patient's gentamicin half-life is 2.5 h. The target is a peak of 10 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.
Answer key
- 1. tss = 50 h
- 2. k = 0.231 h⁻¹
- 3. Vd = 27.5 L
- 4. Vd = 18.57 L
- 5. t = 33.22 h
- 6. τ = 8.3 h
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