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
t/t½C/Css (%)100%3.5f = ?

Practice exercise (made-up values, not clinical guidance). A patient receives lidocaine as a constant IV infusion without a loading dose. The half-life is 1.5 h. What percentage f of the steady-state level has been reached after 5.25 h?

t½ = 1.5 ht = 5.25 h
f = %
2.Easy
110100t (h)CC₀t½ = ?C₀/2

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

k = 0.347 h⁻¹
t½ = h
3.Medium
VCss​ = 15 mg/LR = ? mg/h · S = 0.8CL = 0.04 L/kg/h82 kg

Practice exercise (made-up values, not clinical guidance). An 82 kg patient is to receive an aminophylline infusion (salt factor S = 0.8: 80% of aminophylline is theophylline). The theophylline clearance is 0.04 L/kg/h. What aminophylline infusion rate R in mg/h gives a steady-state theophylline level of 15 mg/L?

82 kgCL = 0.04 L/kg/hCss = 15 mg/LS = 0.8
R = mg/h
4.Medium
Vd = 0.7 L/kgC = 15 mg/LLD = ? mg79 kg · S = 0.92 · F = 1

Practice exercise (made-up values, not clinical guidance). A 79 kg patient is to be loaded intravenously with phenytoin sodium to reach a phenytoin level of 15 mg/L. The volume of distribution is 0.7 L/kg and the salt factor is S = 0.92. Find the loading dose LD of phenytoin sodium in mg.

79 kgVd = 0.7 L/kgC = 15 mg/LS = 0.92
LD = mg
5.Hard
VCss,avg​ = ?450 mg · q8hCL = 0.045 L/kg/h67 kg · S = 1 · F = 1

Practice exercise (made-up values, not clinical guidance). A 67 kg patient takes oral theophylline (F = 1) every 8 h. The clearance is 0.045 L/kg/h. Each dose is 450 mg of theophylline. Find the average steady-state level Css,avg.

CL = 0.045 L/kg/hτ = 8 hS = 1F = 167 kgD = 450 mg
Css,avg = mg/L
6.Hard
Vd = 0.7 L/kg12 → 20 mg/LLD = ? mg61 kg · S = 0.92 · F = 1

Practice exercise (made-up values, not clinical guidance). A 61 kg patient has a phenytoin level of 12 mg/L; the target is 20 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?

61 kgVd = 0.7 L/kgC = 12 → 20 mg/LS = 0.92
LD = mg

Answer key

  1. 1. f = 91.16 %
  2. 2. t½ = 1.998 h
  3. 3. R = 61.5 mg/h
  4. 4. LD = 901.6 mg
  5. 5. Css,avg = 18.66 mg/L
  6. 6. LD = 371.3 mg

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