Effects of cisapride on QTc interval in term neonates

BACKGROUND: Cisapride administration for 48 hours has been shown to increase heart rate corrected QT (QTc) interval in preterm neonates. Accumulation of the drug because of liver enzyme immaturity has been suggested to be the reason. If this is correct, a longer survey of QTc interval should disclose an increase even in term neonates. OBJECTIVE: A prospective survey of the effects of cisapride on QTc interval in term neonates administered cisapride. SETTING: Neonatal Unit of the University Hospital of Dijon, France. DESIGN: QTc interval was determined just before and 48 hours, seven days, and 15 days after the start of treatment. SUBJECTS: Twenty one term newborn infants (mean gestational age 39.3 weeks) given the recommended dose of cisapride (0.2 mg/kg, four times a day). RESULTS: Administration of cisapride caused a significant increase in QTc interval (p < 0. 01). The mean value increased from 0.397 before treatment to 0.418 after 48 hours, 0.431 by day 7, and 0.447 by day 15. A QTc interval exceeding 0.450 was found in six neonates: three at 48 hours, one at day 7, and two at day 15. In two infants, withdrawal of the drug was associated with normalisation of the QTc interval. CONCLUSIONS: These results support the hypothesis of cisapride accumulation in newborns due to enzymatic immaturity and indicate that QTc interval should be monitored in neonates receiving this drug.