Oral cimetidine prolongs clarithromycin absorption.

Author(s): Amsden GW, Cheng KL, Peloquin CA, Nafziger AN

Affiliation(s): Clinical Pharmacology Research Center, Bassett Healthcare, Cooperstown, New York 13326, USA. amsden@telenet.net

Publication date & source: 1998-07, Antimicrob Agents Chemother., 42(7):1578-80.

Publication type: Clinical Trial; Randomized Controlled Trial

The present study was conducted to identify any potential interaction between oral cimetidine and clarithromycin. Twelve healthy subjects were administered single doses of clarithromycin alone and with oral cimetidine dosed to steady state. Cimetidine prolonged the absorption of clarithromycin, as evidenced by decreased peak concentrations of both clarithromycin and 14-OH-clarithromycin (14OHC) in serum (46 and 43%, respectively), a delay in the formation of 14OHC (increase of 68%), and increases in both of their half-lives (75 and 82%, respectively), despite no changes in total oral clearance or area under the concentration-time curve for either compound. No mechanism for this interaction has been identified.