THE EFFECT OF 3 DIFFERENT RANITIDINE DOSAGE REGIMENS ON REDUCING GASTRIC-ACIDITY AND VOLUME IN AMBULATORY SURGICAL PATIENTS

Study Objective. To evaluate three different preoperative oral dosing regimens oi ranitidine in ambulatory patients who had significant risk of aspiration pneumonitis (gastric pH less than or equal to 2.5 or vo lume greater than or equal to 25 ml at intubation or extubation). Desi gn. Double-blind, placebo-controlled, randomized trial. Setting. St. F rancis Hospital of Buffalo, New York. Patients. Two hundred seventy-on e ambulatory patients about to undergo a surgical procedure under gene ral anesthesia, of whom 241 (89%) completed the trial and were conside red evaluable. Interventions. Patients were randomly assigned to recei ve one of four regimens administered orally before surgery: placebo at bedtime the night before and in the morning on the day of surgery; ra nitidine 150 mg at bedtime and in the morning; ranitidine 150 mg at be dtime and placebo in the morning; or ranitidine 300 mg at bedtime and placebo in the morning. Measurements and Main Results. Patients who re ceived ranitidine 150 mg twice/day, ranitidine 150 mg at bedtime, or r anitidine 300 mg at bedtime had a significantly (p<0.05) lower frequen cy of a gastric pH 2.5 or below at intubation or extubation than those taking placebo twice/day (3%, 45%, and 31%, respectively, vs 86%). In addition, gastric volume at intubation or extubation was 25 ml or abo ve in significantly fewer patients receiving ranitidine 150 mg at bedt ime than placebo (37% vs 13%, p<0.05). Overall, the number of patients with risk factors for aspiration pneumonitis was significantly lower with ranitidine 150 mg twice/day (20%), ranitidine 150 mg at bedtime ( 48%), and ranitidine 300 mg at bedtime (35%) than placebo (86%) (p<0.0 01), and significantly lower with ranitidine 150 mg twice/day than ran itidine 150 mg at bedtime (p<0.05). Conclusions. Ranitidine 150 mg twi ce/day preoperatively reduced to the greatest degree the percentage of patients who developed significant risk factors for aspiration pneumo nitis after surgery under general anesthesia.