Background: It has been presumed that nocturnal acid breakthrough may pose a risk for the development of nocturnal gastro-oesophageal reflux.

Aim: To investigate the occurrence of gastro-oesophageal reflux and acid breakthrough during polygraphically monitored sleep under conditions of powerful acid suppression with omeprazole 20 mg b.d. and an additional dose of ranitidine at bedtime.

Methods: Nineteen individuals with symptomatic gastro-oesophageal reflux disease were studied. Each individual was studied on two occasions subsequent to 1 week of 20 mg of omeprazole treatment b.d. Subjects underwent 24-h oesophageal and gastric pH recording, with polysomnographic monitoring. Participants received either 150 mg ranitidine at bedtime or placebo, prior to a provocative meal.

Results: Ranitidine administration resulted in a significant (P < 0.01) reduction in the percentage of time the intragastric pH < 4.0. There was no significant difference with regard to measures of gastro-oesophageal reflux, and reflux events were not noted to occur with a significantly greater frequency during periods of nocturnal acid breakthrough compared with control intervals without acid breakthrough.

Conclusions: The administration of 150 mg ranitidine at bedtime did not significantly alter the occurrence of sleep-related gastro-oesophageal reflux.