[Influence of cimetidine on bacterial growth in gastric fluid (author's transl)]

Samples of gastric fluid were tested for pH and number of bacteria in 20 patients who received cimetidine 400 mg prior to selective gastric surgery. The results were compared with those obtained in a group of surgical patients who did not receive the drug. The cimetidine-treated patients had alkaline gastric fluid with pronounced bacterial growth (4.7 +/- 0.6 x 10(4) micro-organisms/ml), whereas 18/20 untreated patients has a sterile gastric fluid. Similar results were observed in 14 intensive care patients treated for 24 hours with cimetidine. The effect proved reversible: 12 hours after treatment was discontinued bacterial growth could only be demonstrated in 3/14 patients. Thus, short-term cimetidine treatment results in a rise of gastric pH with marked bacterial proliferation. This may have serious consequences in cimetidine-treated patients about to undergo gastric surgery or likely to develop aspiration pneumonia.