In the prophylaxis of stress ulcers with antacids in young infants there are no recommendations of dosages that consider the physiologic maturation of gastric acid secretion. During the first six month of life the amount of gastric acid secretion in relation to body weight and body surface area increases exponentially. Therefore adult dosages of antacids cannot be transferred to infants.
Methods: In a cross over study 12 infants aged between 4 and 174 days, who had been undergoing a cardiosurgical intervention with the heart lung machine, were treated during 48 hours with 2 different antacid regimens over a period of 24 hours each, monitoring the gastric pH continuously. The used antacid consisted of an aluminium-magnesium complex (Al(OH)3, 90 mg/ml and Mg(OH)2, 60 mg/ml): Regimen A: 6 x 0.5 ml per kg body weight. Regimen B: 0.25 ml per kg body weight at a gastric pH less than 3, with the pH read every 30 minutes.
Results: Compared to 28 applications under regimen B, 72 single doses were given under regimen A, 58 of them at a gastric pH of higher than 3. Thus, the mean administered dose was significant lower under regimen B (2.2 ml) than under regimen A (12.0 ml). Consequently, the mean level of gastric pH was higher under regimen A (median: 5.96 +/- 1.31 versus 4.94 +/- 1.16). pH-values lower than 3 were more often measured under regimen B, whereas the phases at this pH-level were longer under regimen A.
Conclusion: The usual body weight related dosage of antacids seems to be to high for early infancy. In the face of the discrepancy of the administered antacid quantity comparing regimen A with regimen B, it seems to be reasonable for the studied age group to reduce the single antacid dose to 0.25 ml/kg body weight while adhering to a high application frequency of 6 times a day.