The effects of theophylline on renal function in the premature newborn.

The effects of aminophylline on renal function in 10 premature infants with idiopathic apnea are evaluated. The percent increases in creatinine clearance (128 +/- 339%, mean +/- SD) and sodium clearance (196 +/- 304%, mean +/- SD) are variable while the percent increase in fractional sodium excretion (69 +/- 109%, mean +/- SD) is significant. This effect is postulated to be at the proximal tubule and may be modified by the effects of postnatal age and infusion of albumin. Gestational age, birth weight, heart disease, water and sodium intake and ventilatory support did not appear to influence the results. Hyponatremia is a potential consequence of theophylline therapy for apnea.