Prophylaxis against acid aspiration syndrome. Single oral dose of H2-antagonist on the evening before elective surgery.

We have compared famotidine 40 mg, ranitidine 300 mg and placebo given in a single oral dose at 2200 hours as the sole means of prophylaxis in 286 patients who underwent elective surgery the following day. Standardised premedication was administered and anaesthesia induced. Gastric contents were aspirated by nasogastric suction and the pH and volume measured. Median values of pH after famotidine, ranitidine and placebo were 6.17, 6.74 and 2.45 respectively; median aspirate volumes were 8, 8 and 10 ml respectively. The proportions of patients considered 'not at risk' (pH greater than 2.5) were 90% after famotidine, 91% after ranitidine and 52% after placebo. We conclude that the administration of a potent H2-antagonist in a single oral dose at night offers a convenient routine means of providing extensive prophylactic cover in patients scheduled to undergo elective surgery the following day.