Practice exercise (made-up values, not clinical guidance). In a patient, digoxin has an elimination half-life of 36 h. Find the elimination rate constant k in h⁻¹.
Clinical pharmacokinetics worksheet with answers
Practice exercise (made-up values, not clinical guidance). A patient starts regular doses of phenobarbital, which has a half-life of 100 h. Using the rule that steady state is reached after about five half-lives, after how many hours tss is steady state reached?
Practice exercise (made-up values, not clinical guidance). After an IV dose of tobramycin, the level is 8 mg/L at 2 h and 1.3 mg/L at 10 h. Assume first-order elimination. Find the half-life t½.
Practice exercise (made-up values, not clinical guidance). After an IV dose of vancomycin, the level is 30 mg/L at 1 h and 6.2 mg/L at 17 h. Assume first-order elimination. Find the elimination rate constant k.
Practice exercise (made-up values, not clinical guidance). A 55 kg patient takes oral theophylline (F = 1) every 8 h. The clearance is 0.03 L/kg/h. What dose D in mg gives an average steady-state level of 15 mg/L?
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 6 mg/L and a trough of 1 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?
Answer key
- 1. k = 0.01925 h⁻¹
- 2. tss = 500 h
- 3. t½ = 3.052 h
- 4. k = 0.09854 h⁻¹
- 5. D = 198 mg
- 6. D = 65 mg
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