Percutaneous administration of theophylline in the preterm infant

The preterm infant's skin is a poor barrier to the absorption of chemical agents. The possibility of turning this to the infant's advantage was explored by using the percutaneous route to administer theophylline. A standard dose of theophylline gel, equivalent to 17 mg anhydrous theophylline, was applied to an area of skin 2 cm in diameter over the upper abdomen under an occlusive dressing, and serial theophylline levels were measured; 25 studies were performed in 20 infants of less than or equal to 30 weeks gestation. Therapeutic theophylline levels (greater than 4 mg/L) were achieved in 11 of 13 infants who had not previously received the drug, and were maintained for up to 72 hours. In 12 studies in infants who were previously receiving aminophylline intravenously, theophylline levels were maintained for up to 70 hours. There was a significant decline in the amount of theophylline absorbed in the first 24 hours after application as the infant's postnatal age increased, but satisfactory blood levels were achieved in infants up to 20 days of age. The percutaneous route is a feasible method of administering theophylline in preterm infants.