Urinary excretion of prostaglandin E following the administration of furosemide and indomethacin to sick low-birth-weight infants.

Urinary excretion of prostaglandin E was measured in seven sick low-birth-weight infants. Four had severe hyaline membrane disease and one had chronic bronchopulmonary dysplasia; all received furosemide. Two infants had patent ductus arteriosus and received indomethacin. Following administration of furosemide, urine volume and the excretion rates of sodium and calcium were significantly increased; such changes were not seen following the administration of indomethacin. Prostaglandin E excretion rate was increased from 0.4 +/- 0.04 to 1.3 +/- 0.2 ng/mg Cr (mean +/- SEM) following administration of furosemide, but decreased in two patients following administration of indomethacin. The present results demonstrate that furosemide enhances urinary excretion of prostaglandin E by mechanisms which may reflect an increase in prostaglandin synthesis, a decrease in prostaglandin renal metabolism, or both. Indomethacin, which is a prostaglandin synthetase inhibitor, decreases the urinary excretion of prostaglandin E. These observations suggest that furosemide therapy in patients receiving indomethacin may be ineffective.