Multi-dose Pharmacokinetics and Dose Ranging of Inositol in Premature Infants (INS-2)

Retinopathy of prematurity (ROP) is an abnormal growth of the blood vessels in the eye that occurs primarily in very premature infants. Eye development occurs normally in the womb; in infants born prematurely, however, the blood vessels must finish developing outside the protective environment of the uterus. Retinopathy of prematurity (also known as retrolental fibroplasia) is a leading cause of blindness and other vision impairments (myopia, strabismus, and amblyopia) in children, both in developed and developing countries. Inositol is a naturally-occurring sugar alcohol produced by the fetus and placenta and is present in high levels in fetal blood throughout pregnancy in humans and other animals. Serum levels fall rapidly after birth, although this fall is moderated in infants who receive breast milk or fortified formula. Two randomized trials have shown that intravenous inositol supplementation in the first week significantly reduced death, bronchopulmonary dysplasia (BPD), and retinopathy. One study of enteral supplements (given orally or via feeding tube) was less convincing, but also supported reduction of retinopathy. This pilot study will evaluate changes in blood and urine inositol levels (half-life pharmacokinetics) of multiple doses of myo-inositol (provided by Abbott Laboratories, Abbott Nutrition Division) given to very low birth weight infants. The premise is that maintaining inositol concentrations similar to those occurring naturally in utero will reduce the rates of retinopathy and bronchopulmonary dysplasia in premature infants. Results from this study will be used to select the dose for a large multi-center trial. In this study, 17 NICHD Neonatal Research Network sites will enroll approximately 96 infants at 12-72 hours of age. Enrolled infants will be randomly assigned to receive either 10mg/kg of 5% inositol, 40 mg/kg of 5% inositol, 80 mg/kg of 5% inositol, or 5% glucose given in the same volumes and timings as the inositol dosage to maintain masking. Inositol will be administered intravenously until babies are feeding normally, at which time the same dose and formulation will be administered enterally (orally or via feeding tube). Concentrations of inositol will be measured in blood, urine, and milk received. Stratification: Recruitment will be stratified by gestational age into infants born at 23 0/7 to 26 6/7 weeks gestational age and infants born at 27 0/7 to 29 6/7 weeks gestational age.