A retrospective study of nine sick premature infants with chronic lung disease who received captopril for control of systemic hypertension (systolic blood pressure (BP) greater than 113 mm Hg) was carried out to determine efficacy of therapy and associated complications. All nine infants had markedly elevated peripheral renin values, 134.3 +/- 128.1 ng/mL/hr (mean +/- SD). Five infants had abnormal renal sonographic and perfusion scans with evidence of renal artery thrombosis, parenchymal disease, or both. Captopril therapy (0.3 mg/kg) was instituted at a postnatal age of 123 +/- 108 days. After the initial dose, the systolic BP decreased significantly in all infants, the decrease ranging from 21% to 58% of the pretreatment value. Dosage was subsequently halved in all infants. Seventeen episodes of unpredictable decreases in BP more than 40% from baseline occurred during the reduced maintenance therapy. Four infants had a total of seven episodes during which the BP decreased by 57 +/- 10% from baseline; this decrease persisted for 17 +/- 6 hours and was unresponsive to volume reexpansion and inotropic therapy. All seven episodes were accompanied by oliguria (urine output less than 1 mL/kg/hr) that persisted for 18 +/- 12 hours. These episodes were accompanied by neurologic signs (subtle seizures, lethargy, and/or apnea) within 18 +/- 6 hours after the onset of oliguria. The remaining five infants had a total of 13 episodes of decreased BP of 50 +/- 8% of baseline, which were of significantly shorter duration and responded to volume reexpanders, inotropic therapy, or both and were unaccompanied by oliguria. These data suggest the need for close observation of BP in infants receiving maintenance captopril therapy.
