Night-time doses of ranitidine have been shown to help in the healing of duodenal and gastric ulcers. A study was designed to determine the potential of larger doses of ranitidine on 24-hour intragastric acidity in duodenal ulcer patients.

In all, 12 patients with duodenal ulcers, in symptomatic remission, were included in the study. They were subjected to three separate 24-hour studies, at least a week apart, on the third day of treatment with placebo, ranitidine 300 mg nocte and ranitidine 300 mg b.d.

Median 24-hour acidity was 79.4 mmol/l with placebo. It came down to 28.2 mmol/l during treatment with ranitidine 300 mg nocte and to 3.6 mmol/l during treatment with ranitidine 300 mg b.d. (P < 0.02 and P < 0.001, respectively, compared to placebo). Median nocturnal acidity with placebo treatment was 100 mmol/l. It decreased to 0.1 mmol/l with bedtime ranitidine treatment, and to 0 mmol/l with twice-daily ranitidine treatment (P < 0.0005 for both compared with placebo).

The two ranitidine regimens led to reduction in intragastric acidity to a similar degree during the night. While a prolonged decrease of acidity was attained with ranitidine 300 mg b.d., investigators confirmed that H2-receptor antagonists are considerably more effective during the nighttime than during the day.

Source: Merki HS, Witzel L, Walt RP, et al. Comparison of ranitidine 300 mg twice daily, 300 mg at night and placebo on 24-hour intragastric acidity of duodenal ulcer patients. Aliment Pharmacol Therap. 1987;1(3):217-223.