Treatment of primary pulmonary hypertension with oral sildenafil.

Sildenafil, a selective phosphodiesterase-5 inhibitor, was administered orally to a 14-year-old girl with primary pulmonary hypertension (PPH) at a dose of 0.5 mg/kg/4 h on a daily basis, increased to doses of 1 and 2 mg/kg at monthly intervals. Following therapy, oxygen saturation increased and exercise capacity improved significantly, but with no change in pulmonary haemodynamics. No side-effects were noted. Sildenafil may be beneficial in children with PPH, but the mechanism of benefit is unclear.