Suppression of gastric acid secretion by intravenous administration of famotidine in children.

This study was designed to establish appropriate dosing requirements for intravenous use of famotidine, a new H2-receptor antagonist, in pediatric patients. Eighteen children, 2 to 69 months of age (mean +/- SD: 31 +/- 23 months), were treated with intravenously administered famotidine to prevent bleeding of the upper gastrointestinal tract. Continuous intragastric pH monitoring was carried out to ascertain the effectiveness of various intravenous doses. An initial dose of 0.4 mg/kg was given and repeated only after the intragastric pH had dropped to less than 4.0 for 2 hours. Increased doses were given (0.8, 1.2, and 1.6 mg/kg) if the previous dose did not raise the intragastric pH to greater than 4.0 for greater than or equal to 6 hours. Sixteen patients achieved an intragastric pH greater than or equal to 4.0 for greater than or equal to 6 hours, 13 with a dose of 0.4 mg/kg, and three with a dose of 0.8 mg/kg. The mean duration of continuous pH greater than 4.0 per dose was 9.0 +/- 7.5 hours. Ten patients received two or more intravenous doses of famotidine; the mean duration of pH greater than 4.0 after the second dose was less than that after the first (14.9 +/- 8.0 hours vs 6.9 +/- 3.2 hours, p less than 0.01). We conclude that intravenous famotidine therapy raises gastric pH to greater than 4.0 for approximately 9 hours in most children. Prolonged intravenous use of famotidine rapidly leads to a decreased duration of efficacy, necessitating intragastric pH monitoring to assess the effectiveness of treatment.