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 received oral cyclosporine at baseline, after the first week of 1 histamine2 (H2)-blocker, and a third time after a 1-week washout plus 1 week of the second H2-blocker. Blood samples were collected just before each dose of cyclosporine and for up to 36 hours afterward for pharmacokinetic analysis.Setting:A college of pharmacy in a university teaching hospital.Participants:The study population consisted of 8 healthy men at least 19 years of age.Main Outcome Measures:Cyclosporine concentrations in whole blood were measured using a polyclonal fluorescence polarization immunoassay. Cyclosporine pharmacokinetic parameters during each of the 3 treatment periods were compared.Results:The average times to maximum cyclosporine concentrations were similar between baseline (3.2 h), cimetidine (2.9 h), and famotidine (3.6 h) dosing periods. There were no significant differences in ar...