Effects of two dosing regimens of intravenous ranitidine on gastric pH in critically ill children

BACKGROUND: Gastric bleeding in children is associated with critical illness, shock, and physical trauma. Histamine-2 receptor antagonist therapy is used prophylactically to treat gastric bleeding, but it is not known whether bolus dosing or continuous infusion dosing is more effective. OBJECTIVES: To compare the effects of continuous infusion intravenous ranitidine and intravenous bolus dosing of ranitidine on gastric pH in critically ill children and to look for correlation between illness severity scores and gastric pH. METHODS: Sixteen critically ill children were randomized into two groups. Children in group 1 received bolus dosing on day 1 and continuous infusion of ranitidine on day 2. Group 2 received the continuous infusion on day 1 and bolus dosing on day 2. Equivalent doses of ranitidine were based on weight. Continuous infusion regimen: ranitidine bolus of 0.15 mg/kg followed by continuous infusion at 0.15 mg/kg per hour for 12 hours. Bolus regimen: 1 mg/kg, two doses 6 hours apart. Pediatric risk of mortality scores were recorded upon admission to the study. RESULTS: There was no statistically significant difference between regimens. Both raised gastric pH values above 4.0 during the treatment phase. There was no correlation between illness severity scores and gastric pH values. CONCLUSIONS: Both bolus dosing and continuous infusion dosing of 4 mg/kg per day of intravenous ranitidine were effective at raising and maintaining gastric pH in critically ill children.