Side effects of stress bleeding prophylaxis.

Conventional stress bleeding prophylaxis with antacids or histamine (H2)-antagonists, as well as the newer mucosa-protective drugs pirenzepine and sucralfate, are satisfying most of the clinicians with regard to efficacy of stress bleeding prevention. Therefore, potential side effects are attaining crucial importance with regard to the drugs to be used. Pharmacologic blockade of cardiac H2-receptors increases the risk of bradycardia and negative inotropic effects as well as coronary vasoconstriction at least in the presence of elevated plasma histamine levels. Intracardiac injection of pirenzepine can lead to temporary tachycardia. Elderly patients have been shown to be at an increased risk of side effects to the central nervous system when treated with H2-antagonists. These drugs can also induce toxic effects in the liver. Cimetidine leads to interactions with a number of drugs used in the intensive care unit. In patients with pre-existing pulmonary diseases, H2-antagonists have been demonstrated to increase pulmonary bronchoconstriction. Alkalinization of the gastric juice is associated with a significant increase in colonization of gram-negative bacteria in the stomach. In intubated patients, aspiration of stomach contents occurs in 30 to 40 percent of the patients. A number of studies have shown a direct correlation between alkalinization of the gastric juice and pulmonary infections. Sucralfate and to a lesser degree pirenzepine can reduce the risk of pulmonary infections. Sucralfate also exerts a bactericidal effect. Recent investigations support the hypothesis that alkalinization of the stomach also increases the risk of systemic infections. This may be the main reason for the observation that at least in ventilated patients sucralfate, unlike H2-antagonists or antacids, leads to a significant reduction of the mortality rate compared with conventional stress bleeding prophylaxis.