[The effect of ranitidine on postoperative monocyte and neutrophil granulocyte function]

The histamine H-2-receptor antagonist ranitidine hydrochloride has been shown to alleviate trauma-, blood transfusion- and sepsis-induced immunosuppression. We evaluated the effect of ranitidine on the postoperative impairment of monocyte and neutrophil function in 24 patients undergoing major elective abdominal surgery. The patients were randomized to receive postoperative adjuvant treatment with ranitidine hydrochloride (100 mg) administered intravenously twice daily for four days, followed by oral ranitidine hydrochloride (150 mg) administered twice daily for five days (n = 11), or no adjuvant treatment (n = 13). Blood monocyte and neutrophil chemotaxis and chemiluminescence were analyzed before the operation and on post-operative days one, three and nine. Monocyte chemotaxis to C5a in the 13 control patients was significantly decreased on day one compared to day 0. Chemotaxis in the 11 ranitidine-treated patients increased significantly from day 0 to day one (p < .01 between groups). Neutrophil chemiluminescence to zymosan and N-f-methionyl-leucylphenylalanine was significantly increased in control patients on day one compared to day 0 (p < .05), while ranitidine reduced chemiluminescence to zymosan insignificantly on day one (p < .07 between groups). Five of the 13 control patients developed postoperative infectious complications, which were related to decreased monocyte chemotaxis to C5a and increased neutrophil chemiluminescence to zymosan when compared to noninfected patients. A significant difference (P < .05) in chemiluminescence to zymosan between infected and noninfected control patients was observed on day three, before clinical signs of infectious disease could be detected. There were no infectious complications in ranitidine-treated patients. These results support previous studies on the effect of ranitidine in reducing postoperative immunosuppression.