EVALUATION OF THE PHARMACOKINETIC INTERACTION BETWEEN CIMETIDINE OR FAMOTIDINE AND CYCLOSPORINE IN HEALTHY-MEN

OBJECTIVE: To investigate the potential interaction between cimetidine or famotidine and cyclosporine in healthy men. DESIGN: All subjects r eceived oral cyclosporine at baseline, after the first week of 1 hista mine(2) (H-2)-blocker, and a third time after a 1-week washout plus 1 week of the second H-2-blocker. Blood samples were collected just befo re each dose of cyclosporine and for up to 36 hours afterward for phar macokinetic analysis. SETTING: A college of pharmacy in a university t eaching hospital. PARTICIPANTS: The study population consisted of 8 he althy men at least 19 years of age. MAIN OUTCOME MEASURES: Cyclosporin e concentrations in whole blood were measured using a polyclonal fluor escence polarization immunoassay. Cyclosporine pharmacokinetic paramet ers during each of the 3 treatment periods were compared. RESULTS: The average times to maximum cyclosporine concentrations were similar bet ween baseline (3.2 h), cimetidine (2.9 h), and famotidine (3.6 h) dosi ng periods. There were no significant differences in area under the cu rve, half-life, or maximum concentration during the 3 dosing periods. CONCLUSIONS: Neither cimetidine or famotidine produced a significant c hange in the pharmacokinetics of single-dose oral cyclosporine in heal thy men.