エンドセリン受容体拮抗薬によりエポプロステノール持続静注療法から離脱しえた特発性肺動脈高血圧症の1例

Switchover from Intravenous Epoprostenol Therapy to Oral Bosentan Therapy in a Patient with IPAH

要旨　患者は39歳，女性．特発性肺動脈高血圧症の診断で2004年12月よりエポプロステノールの持続静注療法を導入し，通院加療を続けていた．2005年12月，自宅で中心静脈留置カテーテルが抜けてしまい，当科に緊急入院となった．以前からヒステリー様精神発作やカテーテル損傷などで入退院を繰り返しており，エポプロステノール持続静注療法を継続するうえでの障害が少なくないことから，ボセンタン内服療法への切替えを試みた．62.5mg/日よりボセンタンの内服を開始し，肺動脈圧の上昇がないことを確認しながらエポプロステノールの減量を行った．約4週間後ボセンタンを250mg/日まで増量，ベラプロスト60μg/日の内服を追加し，エポプロステノール持続静注療法からの完全離脱に成功した．この間，ボセンタンによる副作用は出現せず，さらには切替えによる病態の悪化も認められなかった．

　In the case of a 39-year-old woman with idiopathic pulmonary arterial hypertension(IPAH) being treated with intravenous epoprostenol therapy, we attempted to change the treatment to oral bosentan therapy. During her initial admission to our hospital in 2004, intravenous epoprostenol therapy was introduced as a treatment for IPAH, and her health condition improved. She was discharged from the hospital and went back to her daily life with a portable continuous injection pump system. However, she often suffered from mental attacks like hysterics, which made it difficult for her to prepare the epoprostenol by herself. In addition, she had catheter troubles including a pin-hole rupture and the pulling out of the catheter used for the continuous intravenous injection. Because of these factors, we decided to change the epoprostenol therapy to oral bosentan therapy in order to reduce her stressful daily tasks. In December, 2005, with her pulmonary arterial pressure monitored by echocardiogram, bosentan was administered at a low dose(62.5 mg/day), and the amount of the epoprostenol injection was gradually decreased. In January, 2006, we successfully completed the transition from intravenous epoprostenol to oral bosentan(250 mg/day) without any worsening of the parameters for the disease such as pulmonary artery pressure, BNP value, and 6-minute walk distance. Although evidence of the safety and efficacy of the switchover from epoprostenol to bosentan has not yet been fully established, it may be a considerable option for some IPAH patients having trouble with continuous intravenous epoprostenol therapy.