Time of administration influences gastric inhibitory effects of ranitidine.

The overnight gastric secretion of patients with duodenal ulcer or oesophagitis and of healthy volunteers known to be gastric nocturnal hypersecretors was studied after administration of ranitidine at 1815 h or 2200 h. Patients with oesophagitis showed a significant therapeutic 'gain' after the earlier (1815 h) dosing, with gastric inhibition lasting an average of 5 h longer. A similar pattern was observed in the nine patients with duodenal ulcer, although three of these patients showed some degree of escape from the gastric inhibition after 0400 h following the 1815 h administration of ranitidine. All of the volunteers also had better inhibition before midnight with the earlier dosing, but after midnight the gastric inhibition was significantly less after the 1815 h than after the 2200 h dosing with ranitidine. We conclude that early evening dosing with ranitidine is the treatment of choice for patients with reflux oesophagitis. However, bedtime administration of ranitidine is preferable for individuals with gastric hypersecretion, since earlier dosing may result in failure to inhibit gastric secretion satisfactorily during most of the night.