Prevention of stress bleeding with ranitidine or pirenzepine and the risk of pneumonia.

In a prospective, controlled, randomized trial of stress bleeding prophylaxis, 400 patients in a surgical intensive care unit received 50 mg pirenzepine (n = 200) or 200 mg ranitidine (n = 200) daily. The drugs were administered continuously via an intravenous line. The mean duration of the treatment was 3.9 days. Patients were included in the study if no long-term ventilation was expected. In patients with a stomach tube in place, the intragastric pH was determined every eight hours. Bleeding was defined as macroscopically visible. Along with stress bleeding, the development of postoperative pneumonia was documented. The intragastric pH was less than 4 significantly more often in patients treated with pirenzepine. In patients treated with ranitidine, six stress bleedings were observed, while in the pirenzepine group three bleeding episodes occurred. Seven of the nine bleeding patients were found to have a very high bleeding risk. In mechanically ventilated patients, a significantly higher risk of pneumonia was observed compared with non-ventilated patients (18.0% vs 2.7%). Fourteen of the 20 pneumonias occurred in patients treated with ranitidine. In ventilated patients treated with ranitidine, the pneumonia rate was 28.6%, while in the pirenzepine group the pneumonia rate reached only 9.1% (p less than 0.05). The increased frequency of pneumonia in patients treated with ranitidine appears to be caused by overgrowth of gram-negative bacteria in the stomach. Pirenzepine provides adequate protection against stress bleeding while also minimizing the danger of pneumonia caused by infection via the gastropulmonary route.