Effect of ranitidine on intragastric pH in clinically normal neonatal foals

Abstract

Objective To determine intragastric pH in newborn foals and to examine the effect of IV or oral administration of an H2-receptor antagonist on intragastric pH. Design Prospective controlled study. Animals 6 healthy mixed-breed neonatal foals. Procedure Intragastric pH was measured, using an antimony electrode. Foals were monitored on days 2, 4, and 6 after birth, and each received 3 treatments. The pH was recorded for 4 hours before treatment and for 10 hours after ranitidine administration (2 mg/kg [0.91 mg/lb] of body weight, IV; 6.6 mg/kg [3 mg/lb PO) or 20 hours after corn syrup administration. Mean and median pH and percentage of time pH was ≥ 4 were calculated. Results Mean intragastric pH significantly increased for 5 hours after IV administration of ranitidine, compared with baseline data. Percentage of time intragastric pH was ≥ 4 increased significantly for 4 hours after ranitidine administration, and median pH increased significantly for hours 2 to 4 after administration. Oral administration of ranitidine significantly increased mean and median pH for hours 2 to 8 after administration and percentage of time pH was ≥ 4 for hours 2 to 7 after administration. Clinical Implications Neonatal foals have highly acidic gastric fluid. Intravenous or oral administration of ranitidine significantly increased intragastric pH for 4 and 8 hours, respectively. Suckling affected intragastric pH and underscored the need for frequent feeding of neonatal foals. (J Am Vet Med Assoc 1998; 212:1407–1412)