The comparative effects of single intravenous doses of cimetidine, ranitidine, famotidine, and omeprazole on intragastric PH

Abstract

Twelve healthy subject participated in this randomized, double-masked, four-way crossover study to determine treatment schedules for intravenous (IV) administration of various gastric antisecretory drugs. Intragastric pH was monitored continuously for 14 hours after a single IV injection of cimetidine 300 mg, ranitidine 50 mg, famotidine 20 mg, or omeprazole 40 mg, each administered during one of four succcessive treatment periods separated by 6-day washout periods. The primary efficacy variable, the length of time that intragastric pH remained >3.5, was significantly longer after famotidine treatment (516 ± 143 minutes) than after treatment with cimetidine (355 ± 239 minutes), ranitidine (283 ± 235 minutes), or omeprazole (270 ± 253 minutes). Consequently, the duration of the antisecretory effect (the length of time needed for the pH to return to the baseline level) was also significantly longer after famotidine treatment (635 ± 131 minutes) than after cimetidine (451 ± 259 minutes), ranitidine (414 ± 205 minutes), or omeprazole (393 ± 259 minutes). On the basis of the area under the gastric pH profile curve over 14 hours, famotidine was again shown to be a significantly more effective antisecretory agent than the other three drugs. There were no significant differences between the four agents for maximum pH level achieved, length of time to reach the maximum pH level after drug administration, and length of time between drug administration and the first occurrence of pH level >3.5. No adverse events were recorded during the study.