Interaction of roxatidine acetate with antacids, food and other drugs.

The inhibition of hepatic mixed-function oxidase microsomal enzymes by cimetidine can lead to clinically important drug interactions. The metabolism of antipyrine is used as an index of hepatic enzymatic activity. The pharmacokinetic profiles of salivary antipyrine obtained following treatment with roxatidine acetate 75 mg or placebo twice a day for 7 days showed similar characteristics with no difference in the areas under the plasma concentration-time curves. In addition, roxatidine acetate 75 mg daily did not modify the clearance of propranolol, diazepam, desmethyldiazepam or controlled release theophylline preparations. Furthermore, there was no interference in the bioavailability of roxatidine acetate 150 mg daily when administered alone or in combination with a meal or antacids.