Effect of metoclopramide on prolonged intraesophageal pH testing in infants with gastroesophageal reflux.

The effect of metoclopramide (MCP) on prolonged intraesophageal pH testing was evaluated in 42 infants with gastroesophageal reflux (GER). Following a baseline period of intraesophageal pH monitoring, MCP was administered by injection at 0.1 mg/kg/dose (10 patients), 0.2 mg/kg/dose (11 patients), or 0.3 mg/kg/dose (21 patients). The percentage of time of intraesophageal pH less than 4, reflux frequency, and acid clearance time were calculated for each subject before and after MCP for both 5% dextrose and formula feedings. These parameters were further separated into 2-hour or shorter and more than 2-hour postprandial periods. No significant differences with either type of feeding were noted at either 0.1 or 0.2 mg/kg/dose. Significant decreases in the percentage of time the intraesophageal pH was less than 4 (30.0 +/- 2.9 versus 15.6 +/- 3.1, p = 0.001), the reflux frequency (episodes/hour; 6.5 +/- 0.9 versus 4.0 +/- 0.6, p = 0.004), and the acid clearance time (minutes/episode; 3.8 +/- 0.7 versus 2.2 +/- 0.3, p = 0.047) were noted in the 2-hour or shorter period following 5% dextrose feedings but not following the formula feedings in the subjects receiving 0.3 mg/kg/dose. Three of the 42 study patients developed increased irritability, and one developed dystonia following MCP. These data suggest that if a clinical trial of MCP in infants with GER is performed, a larger dose of the medication than previously appreciated might be required.