Bioequivalence of a new 800-mg cimetidine tablet with commercially available 400-mg tablets

The bioavailability of a new 800-mg tablet of cimetidine was compared with a single dose of two commercially available 400-mg tablets in 23 healthy subjects in a randomized, cross-over study. Mean plasma cimetidine concentration curves, as well as mean values for AUC, C(max), and T(max), were nearly identical for both doses. Bioequivalence of the two dose forms was demonstrated with the Westlake 95% confidence symmetric interval of (0.91; 1.09) for AUC. Comparison of these new data with values previously determined with a variety of cimetidine doses indicates that cimetidine bioavailability and pharmacokinetics are not dose-dependent with single oral doses up to 800 mg.