A drug has a volume of distribution (Vd) of 700 L in a 70 kg patient and a plasma half-life of 30 hours. Calculate the clearance of this drug. (Cl = 0.693 × Vd / t½)

• A 9.87 L/h
• B 16.2 L/h ✓
• C 23.1 L/h
• D 4.85 L/h

Explanation

Using Cl = 0.693 × Vd / t½: Cl = 0.693 × 700 L / 30 h = 485.1 / 30 = 16.17 L/h ≈ 16.2 L/h. This is the correct calculation. Such a high Vd (10 L/kg) suggests extensive tissue binding; drugs like amiodarone, chloroquine, and imipramine exhibit Vd values in this range. The clearance of ~16.2 L/h (270 mL/min) approximates combined hepatic and tissue clearance for extensively distributed drugs.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.