Cimetidine and the potential risk of postoperative sepsis.

The gastric microflora of patients receiving cimetidine for duodenal ulceration has been investigated and the results compared with those from a group of untreated patients. Cimetidine-induced hypochlorhydria allows bacterial proliferation in the stomach; 75 per cent of aspirates from 44 fasting patients taking cimetidine 1 g daily were found to contain bacteria 2--4 h after the last dose. Of 41 patients taking cimetidine 400 mg at night, 34 per cent still had bacteria in their aspirates 12--13 h later. Patients treated with cimetidine are likely to be at an increased risk of postoperative sepsis. The drug should either be withdrawn before gastric surgery is undertaken or patients with gastric contents of pH 4 or above should receive antibiotic cover.