§These authors contributed equally to this work.
§These authors contributed equally to this work.
患者は満期産で仮死なく出生した完全型心内膜床欠損の男児。生後数時間でチアノーゼが出現，純酸素・静注肺血管拡張薬・一酸化窒素吸入療法を行ったが肺高血圧が改善せず，日齢4 にシルデナフィルの経胃管投与を開始した（1mg/kg/d・4時間毎）。急性効果で酸素化改善が得られたが，開始初期に心房頻拍を合併し，超短時間作用型β遮断薬で改善した。少量頻回投与法を行うことで投与量の漸増が可能だった（最終7mg/kg/d・1時間毎）。一時的に一酸化窒素吸入療法が離脱可能となったが肺高血圧が再増悪して日齢66で死亡した。
シルデナフィルは半減期が短く有効投与量の幅が大きい薬剤であり，血中濃度は併用薬や食事の影響を受ける。血行動態が不安定な重症新生児では少量頻回投与などによる慎重な使用が必要と考えられた。
Sildenafil citrate, an oral phosphodiesterase-5 inhibitor, is a selective pulmonary vasodilator that has been used for treatment of pulmonary hypertension in adults.
Our present case is a male term newborn with severe pulmonary hypertension resistant to iNO. We administered oral sildenafil through an orogastric tube at an initial dosage of 1mg/kg/day for every 4 h. Oral sildenafil improved his oxygenation. Initially an side effect of supraventricular tachyarrhythmia was observed, that was treated with Landiolol successfully. On the other hand, mild side effect of flushing was observed during entire treatment period. Multiple lowdose administrations of oral sildenafil was well tolerated, the final dosage was increased to 7mg/kg/day hourly.
We withdrew him from ventilation and iNO temporarily. However, he had a relapse of severe pulmonary hypertension and died, because of hypoxic heart failure at 2 months of age．
However, oral sildenafil is effective for treatment of severe neonatal pulmonary hypertension, it should be used carefully in very sick neonates.
