Oxmetidine: clinical pharmacological studies with a new H2-receptor antagonist

The gastric antisecretory effects of oxmetidine, a new H2-receptor antagonist, have been studied in 33 healthy subjects. The relative potency of oxmetidine compared with that of cimetidine depended on the route of administration and the experimental conditions. Oxmetidine intravenously infused was approximately four times as potent as cimetidine, weight for weight, in inhibiting impromidine stimulated gastric acid secretion but was twice as potent when food was used as a stimulus. After oral administration there were no differences in the weight-for-weight potency of oxmetidine and cimetidine, although oxmetidine was twice as potent on a molar basis. These apparent differences according to the route of drug administration are probably due to first pass metabolism of oxmetidine. There were no differences in the duration of action of oxmetidine and cimetidine. Twenty-four hour monitoring of intragastric pH showed that oxmetidine 400 mg twice daily reduced mean hourly 24 hour intragastric pH by 59%, suggesting that a twice daily dosage regimen should be evaluated in the treatment of duodenal ulceration.