Charcoal and Rifampicin Pharmacokinetics

We investigated the effect of activated charcoal on rifampicin disposition in six healthy subjects. On three occasions (control, phases II and III, separated by 1 week), each subject received 600 mg of rifampicin with 350 ml of water. On the second and third occasions (phases II and III), each subject received in addition to 600 mg of rifampicin and 7.5 and 15 g of activated charcoal, respectively, in 350 ml of water as charcoal slurry. Plasma rifampicin levels were measured from 1 to 24 h postrifampicin ingestion. Treatment with activated charcoal significantly increased the clearance and decreased the maximum peak concentration, half-lives and area under the curves as compared with control treatment without activated charcoal.