Background: Dexamethasone and spironolactone are widely used in the management of bronchopulmonary dysplasia in premature infants. There are few data available about adverse effects of this drugs on the urinary excretion of calcium and phosphate in this group of patients.
Patients: 24 h-urine samples could be collected in 85 infants between 8 and 40 days. 31 infants received dexamethasone and 32 spironolactone.
Methods: Multivariate variance analysis was performed to study the influence of dexamethasone and spironolactone on the measured excretion of calcium and phosphate. The influence of gestational and postnatal age, calcium and phosphate intake and theophylline treatment were excluded by use as covariates.
Results: Spironolactone showed no significant influence on the urinary excretion of calcium or phosphate. Dexamethasone treatment increased the daily excretion of phosphate in the urine and decreased the phosphate concentration in serum.
Conclusion: None of the examined drugs showed a significant increase of the renal excretion of calcium in preterm infants. Thus a higher risk of nephrocalcinosis development due to these drugs has not been confirmed. Dexamethasone treatment might increase the risk of osteopenia by enhancing phosphate excretion.