Increase in serum digoxin concentrations after indomethacin therapy in a full-term neonate

Digoxin was administered to an 18-day-old infant who showed evidence of cardiac failure. When a Doppler echogram revealed a patent ductus, indomethacin was administered for medical management. Therapeutic digoxin doses then resulted in toxic serum concentrations of 8.2 ng/ml. Serum creatinine rose accordingly. Although this patient did not manifest signs of digoxin toxicity, practitioners should be alerted to the potential complications of these commonly used agents.