Influence of the timing of administration of 300 mg ranitidine on 24-hour gastric pH in patients acute duodenal ulcer.

The 24-hour intragastric pH of 12 patients with an acute duodenal ulcer was recorded with the aim of comparing the effects of two different times of administration of 300 mg ranitidine: post evening meal, or bedtime. This double-blind crossover trial involved 3 centres. Twenty-four-hour gastric pH was measured under standard conditions (meals, time schedule) at the middle of each 14-day treatment period. The analysis was performed on the percentage of times spent at pH levels below 1.5, 2, 3 and 4 for different periods and for the total 24 hours. During the whole day and night combined, as well as during the afternoon (12.00 hours-19.00 hours), there was no difference between the 2 regimens regardless of the pH profile studied. During the morning (07.30 hours-12.00 hours), the time spent below pH 1.5 and 2 was less when the drug was taken at bedtime (P less than 0.05). In contrast, during the whole night (19.00 hours-07.30 hours) the percentage of time spent below pH 1.5, 2 and 3 was significantly less when the drug was taken at post evening meal (P less than 0.05). These results show that in patients with acute duodenal ulcer, 300 mg ranitidine administered at the end of the evening meal provides better control of nocturnal acidity than administration at bedtime and hence is suggested for optimization of therapeutic efficacy.