Lack of effect of oral activated charcoal on imipramine clearance

The effect of oral activated charcoal on the pharmacokinetics of intravenous imipramine was studied in a randomized, crossover trial. Four normal men received intravenous imipramine (12.5 mg/70 kg) on two separate occasions, followed by either water or water plus high‐surface‐area activated charcoal (180 gm) in divided doses over 24 hours. Serum imipramine concentrations were measured from 0 to 24 hours after the imipramine infusion. There was no difference in the mean (± SE) t ½ (9.0 ± 0.8 vs. 10.9 ± 1.6 hours), apparent volume of distribution (11.2 ± 2.1 vs. 12.4 ± 2.1 L/kg), or systemic clearance (992.2 ± 138.3 vs. 930.3 ± 101.9 ml/min/70 kg) of imipramine after dosing without and with oral activated charcoal, respectively (P > 0.05; paired t test). These results suggest that multiple oral doses of activated charcoal do not increase the clearance of imipramine in man. Clinical Pharmacology and Therapeutics (1985) 38, 350–353; doi: 10.1038/clpt.1985.184