Clinical pharmacokinetics worksheet with answers

Free printable Clinical pharmacokinetics worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
110100t (h)CC₀t½ = 3 hC₀/2

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.

t½ = 3 h
k = h⁻¹
2.Easy
110100t (h)CC₀t½ = ?C₀/2

Practice exercise (made-up values, not clinical guidance). The elimination rate constant of gentamicin in a patient is 0.347 h⁻¹. Find the half-life t½.

k = 0.347 h⁻¹
t½ = h
3.Medium
110t (h)C (mg/L)1 h8 mg/L6 h3 mg/L

Practice exercise (made-up values, not clinical guidance). After an IV dose of gentamicin, the level is 8 mg/L at 1 h and 3 mg/L at 6 h. Assume first-order elimination. Find the half-life t½.

C1 = 8 mg/L (1 h)C2 = 3 mg/L (6 h)
t½ = h
4.Medium
110t (h)C (mg/L)2 h6 mg/L8 h1.5 mg/L

Practice exercise (made-up values, not clinical guidance). After an IV dose of tobramycin, the level is 6 mg/L at 2 h and 1.5 mg/L at 8 h. Assume first-order elimination. Find the elimination rate constant k.

C1 = 6 mg/L (2 h)C2 = 1.5 mg/L (8 h)
k = h⁻¹
5.Hard
Vd = 0.3 L/kg1 → 8 mg/LD = ? mg60 kg

Practice exercise (made-up values, not clinical guidance). A 60 kg patient on regular gentamicin doses is at steady state. The target is a peak of 8 mg/L and a trough of 1 mg/L, and the volume of distribution is 0.3 L/kg. Assuming rapid IV doses, what dose D raises the level from the trough to the peak?

60 kgVd = 0.3 L/kgCpeak = 8 mg/LCtrough = 1 mg/L
D = mg
6.Hard
78 kg81 · manSCr 1.4 mg/dLfe​ = 0.66D = ? mg

Practice exercise (made-up values, not clinical guidance). An 81-year-old man weighs 78 kg and has a serum creatinine of 1.4 mg/dL (124 µmol/L). Estimate the creatinine clearance with Cockcroft–Gault: CrCl (mL/min) = (140 − age) × weight (kg)/(72 × SCr in mg/dL), × 0.85 for women. The usual levetiracetam dose is 1000 mg for a creatinine clearance of 100 mL/min, and a fraction fe = 0.66 of the drug is excreted unchanged by the kidneys. Using the Dettli dose fraction Q = 1 − fe·(1 − CrCl/normal CrCl), find the adjusted dose D. Round to the nearest whole number.

81 years78 kgmanSCr = 1.4 mg/dL1000 mgfe = 0.66CrCl normal 100 mL/min
D = mg

Answer key

  1. 1. k = 0.231 h⁻¹
  2. 2. t½ = 1.998 h
  3. 3. t½ = 3.533 h
  4. 4. k = 0.231 h⁻¹
  5. 5. D = 126 mg
  6. 6. D = 641 mg

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