bepridilが原因と考えられた薬剤性間質性肺炎の1例

A Case with Bepridil Induced Interstitial Pneumonitis

要旨　患者は76歳，男性．発作性心房粗・細動に対し，2007年2月5日より内服治療を開始した．数種類の抗不整脈薬を試用したが効果なく，4月13日より開始したbepridilで症状は安定した．同年5月末頃より食欲不振，労作時息切れを自覚し6月3日救急受診，低酸素血症，胸部X線写真およびCTで両側下肺野優位にスリガラス様陰影を認め，間質性肺炎として緊急入院となった．入院後，torsades de pointesが出現したため，bepridilの副作用と考え投与を中止し，magnesium sulfate静注で対応した．間質性肺炎に対し原因検索を行うとともに，診断的治療として抗生剤投与，ステロイドパルス療法を施行した．後日得られた結果では感染症，癌性リンパ管症や膠原病肺は否定され，約1週間の経過で呼吸状態や画像所見は改善した．他の原因疾患の除外および一連の経過からbepridilによる薬剤性間質性肺炎と診断した．

　A 76-year-old man had been prescribed for paroxysmal atrial flutter and fibrillation in our hospital since 5th February, 2007. He was administered a kind of antiarrhythmic(the first group) because of arrhythmic attack, but these medicines were inefficacious. On 13th April, 2007, these medications were terminated and, he was prescribedbepridilat150mgdaily.However, the patient developed exertional dyspnea with hypoxemia and appetite loss at the end of May, 2007 and he was admitted to our hospital. The chest X-ray and chest CT scans showed ground-glass pattern with bilateral lower lobes dominance. After hospitalization, he had an attack of torsades de pointes, which we thought had occurred as a side effect of bepridil, and then we gave him an injection of magnesium sulfate. We tried to find the cause of interstitial pneumonitis by combining diagnosis and treatment,administering antibiotics and steroid pulse therapy. Later, the examinations showed that infection, carcinomatous lymphopathy and interstitial pneumonia due to collagen disease did'nt participate as a cause of interstitial pneumonitis. According to the clinical data, the prompt improvement after cessation of bepridil and the absence of other possible causes led us to conclude that bepridil had induced interstitial pneumonitis as a side effect.