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 area under the curve, half-life, or maximum concentration during the 3 dosing periods.

CONCLUSIONS

Neither cimetidine or famotidine produced a significant change in the pharmacokinetics of single-dose oral cyclosporine in healthy men.