Background: The occurrence of phase III of migrating motor complexes in neonates is inversely related to gestational age, and it can be triggered in some infants by the motilin receptor agonist erythromycin. After intragastric erythromycin, the authors determined 1) the occurrence and characteristics of phase III of migrating motor complexes, 2) the antral and duodenal motor responses, and 3) the dose-response relation among preterm and full-term infants.
Methods: Using an unbalanced, repeated measures design, 25 preterm and term infants were given two of three doses of intragastric erythromycin: 0.75, 1.5, and 3.0 mg/kg. Motor activity was recorded 3 hours before and 2 hours after each dose using a continuous water perfusion manometry system.
Results: Erythromycin failed to induce phase III of migrating motor complexes in infants younger than 31 weeks' gestation; however, it induced phase III in a dose-dependent manner among infants whose gestational ages were 32 weeks and older ( P < 0.05). Erythromycin significantly increased the amplitude and frequency of antral contractions in term infants and significantly increased the duodenal contraction amplitude in older preterm and term infants, but these effects were absent in younger preterm infants.
Conclusions: The ontogenic emergence of the motilin receptor-mediated induction of phase III occurs by 32 weeks' gestation, whereas the non-motilin-mediated response of increased antroduodenal motor activity is not observed until term. Therefore, early use of erythromycin as a prokinetic agent may not be useful in very preterm infants, partially useful in older preterm infants, and useful in full-term infants.