ANTISECRETORY EFFECT OF 3 PREMEAL DOSES OF CIMETIDINE 400 MG VERSUS ASINGLE MORNING DOSE OF OMEPRAZOLE 20 MG - PATHOPHYSIOLOGICAL IMPLICATIONS FOR DUODENAL-ULCER TREATMENT

The success of omeprazole in the healing of duodenal ulcer has been at tributed to its profound and almost around-the-clock inhibition of aci d, but the relevance of reducing meal-stimulated acid secretion exclus ively has recently been emphasized in several clinical trials. For thi s reason, we used 24-h continuous intragastric pH monitoring to compar e the pharmacodynamic effects of placebo, three fractioned premeal dos es of cimetidine 400 mg and omeprazole 20 mg mane. Fifteen patients wi th duodenal ulcer in clinical remission were randomized to receive the above medications in single-blind fashion on three separate occasions , at least 2 wk apart. Both active regimens produced higher pH values (p < 0.05-0.001) than placebo, but omeprazole was much more effective than cimetidine (p < 0.01-0.001) during the various time intervals ana lyzed (24 h, evening, nighttime, daytime). The greater effectiveness o f omeprazole was confirmed by its longer-lasting antisecretory action, insofar as the drug increased gastric pH above 3.0 units for about 21 h, whereas the daytime cimetidine regimen maintained this threshold f or 7.30 h (p < 0.001) over the circadian cycle. As these markedly diff erent pharmacodynamic effects have been proven to produce similar fast rates of duodenal ulcer healing in clinical trials, it is reasonable to assume that a small but well addressed reduction of gastric acidity can ensure the same therapeutic benefit as a strong and continuous ac id inhibition. In this light, the acid peaks in response to meals seem to be important pathophysiological events, whose control is sufficien t to permit quick ulcer healing.