TWICE-DAILY NIZATIDINE OR RANITIDINE IS SUPERIOR TO ONCE-DAILY DOSINGIN ELEVATING 24 H INTRAGASTRIC PH IN PATIENTS WITH DUODENAL-ULCER DISEASE

The present study was performed in six asymptomatic patients with a hi story of resistant duodenal ulcers in whom 24 h intragastric pH, gastr ic juice pepsin and PGE(2) concentrations, as well as serum gastrin co ncentrations, were measured. We wanted to compare the effects on these parameters of a single night time (q.h.s.) dose of nizatidine 300 mg (N-1), nizatidine 300 mg b.i.d. (N-2), ranitidine 300 mg q.h.s. (R(1)) or ranitidine 300 mg b.i.d. (R(2)) compared with placebo (P). During the night (22.00-08.00 h), all treatments gave a higher mean pH than P , but during the day (08.00-22.00 h) the mean pH was higher than P onl y for patients administered R(2) and N-2. Doubling the dose of nizatid ine (N-2, vs N-1) or ranitidine (R(2) vs R(1)) increased the mean dayt ime pH, but had no effect on night time pH. The daytime pepsin concent ration was unaffected by H-2-receptor antagonists, while night time pe psin was lower with R(1) and R(2), but not with N-1 or N-2. The night time gastrin concentration was unaffected by H-2-receptor antagonists; doubling the dose of the H-2-receptor antagonist (R(2) vs R(1) and N- 2 vs N-1) increased daytime gastrin concentration. During the night, e ach treatment increased PGE(2) concentration by at least six-fold comp ared with P. Thus, where it is therapeutically indicated to achieve gr eater suppression of acid secretion, doubling the total daily dose by dosing with twice daily versus once daily night time nizatidine or ran itidine is efficacious.