RANITIDINE SUSPENSION OR FAMOTIDINE RESORIBLETTE AND GASTRIC FLUID VOLUME AND PH

We studied the effect of two new formulations of H-2-receptor antagoni sts on gastric fluid pH and volume. Forty-five healthy, elective adult in-patients in three study groups, 15 in each, were premedicated usin g oral diazepam 10 mg with 100 ml of a dose of water soluble suspensio n of ranitidine 300 mg with sodium citrate/bicarbonate, or a resorible tte of famotidine 40 mg, or placebo. Gastric fluid samples were obtain ed by blind aspiration after anaesthesia induction, 50-70 min from pre medication, and again 90 min from premedication. After a mean period o f 60 min from ingestion the patients medicated with H-2-antagonists ha d higher gastric juice pH than those in the control group (1.5 (1.1-6. 3), median (range)) (P < 0.0001) for ranitidine (6.8 (4.1-7.8)) P < 0. 01 for famotidine (3.9 (1.5-7.6)); P < 0.05 ranitidine vs famotidine). Recovered volumes were similar for the groups (median 3-4 ml range 0- 50 ml). None of the H-2 patients had pH < 3.5 and volume greater than or equal to 0.3 ml . kg(-1) (P < 0.05 vs placebo). In second aspiratio ns, taken 90 min from premedication, the group differences from contro l in pH persisted. Famotidine patients had the lowest volumes (P < 0.0 5 vs controls); yet one famotidine patient had a pH < 2.5 and volume g reater than or equal to 0.3 ml . kg(-1). It is concluded that, at the moment of oral anxiolytic premedication, ranitidine-buffer suspension effectively reduced gastric juice acidity, whereas famotidine resoribl ette failed to increase reliably gastric pH in 50-90 min.