A lack of pharmacokinetic interaction between ranitidine and piroxicam

The effects of piroxicam (40 mg) on the pharmacokinetics of ranitidine (150 mg) and of ranitidine (150 mg bid) on the pharmacokinetics of piroxicam (20 mg) were assessed in two 2-way crossover studies in two groups of 18 healthy male subjects. In the first study there were no statistically significant differences between the pharmacokinetic variables for ranitidine in the presence or absence of piroxicam. The mean maximum plasma concentration (Cmax) was 467 ng.ml-1 for ranitidine alone and 466 ng.ml-1 in the presence of piroxicam: mean area under the plasma concentration vs time curve (AUC) was 2460 h.ng ml-1 and 2551 h.ng ml-1 respectively; and the mean terminal half-life (t 1/2) was 3.6 h and 3.8 h respectively. In the second study there were no statistically significant differences between the pharmacokinetic variables for piroxicam in the presence or absence of ranitidine. The mean Cmax was 2.1 micrograms.ml-1 in the presence of placebo and 2.0 micrograms.ml-1 in the presence of ranitidine respectively; mean AUC was 133 h.microgram ml-1 and 137 h.microgram ml-1 respectively, and the mean t 1/2 was 53.6 h and 54.5 h respectively.