CIMETIDINE DOES NOT IMPAIR PULMONARY CLEARANCE OF PSEUDOMONAS-AERUGINOSA IN NORMAL RATS

Histamine (H-2)-receptor blockers are commonly used in critically ill patients to prevent gastric bleeding and have been implicated in the p athogenesis of gram-negative bacterial (GNB) nosocomial pneumonia. The se experiments were undertaken to determine if cimetidine affects pulm onary GNB clearance. Groups of normal Sprague-Dawley rats were given c imetidine (75 mg/kg) or an equal volume of sterile buffer intraperiton eally every 6 hr for 24 hr prior to intratracheal challenge with 1.0 x 10(8) Pseudomonas aeruginosa. At 6 and 24 hr after challenge, animals were sacrificed and gastric pH, quantitative lung cultures, and total and differential [alveolar macrophages (AM) and polymorphonuclear leu kocytes (PMN)] cell counts in bronchoalveolar lavage fluid were perfor med. Results showed that cimetidine therapy resulting in gastric pH gr eater than 4.0 has no effect on the pulmonary clearance of P. aerugino sa.