大建中湯エキスによる薬剤性肺障害が疑われた1例

A Suspicious Case of Drug Induced Lung Injury Caused by Daikenchuto(TU-100)

要旨　【背景】大建中湯は乾式エキス顆粒にしたものが消化器領域で汎用されている．

【症例】76歳，男性．肝細胞がんの手術のため入院し，術後の腸閉塞予防および腫瘍への抗炎症効果を期待して，手術7日前より大建中湯が処方された．術後第4病日より労作時息切れと乾性咳嗽を訴え，胸部単純X線写真で両肺びまん性にすりガラス陰影を認めた．抗菌薬の効果が乏しく，胸部陰影が増悪したため当科を受診した．発症前に服用を開始した大建中湯による薬剤性肺障害を疑い，リンパ球刺激試験で同剤が陽性を示した．同剤の中止後，症状と胸部異常影は軽快し，術後第22病日に治癒した．症状，検査結果，臨床経過より大建中湯による薬剤性肺障害を強く疑った．

【考察】大建中湯は処方頻度が最多の漢方製剤であるが，副作用の発現頻度調査で，肺障害の報告は稀少である．しかし，投与後に呼吸器症状や胸部X線で異常影を呈した際には原因の一つとして考慮すべきである．

　Background:Daikenchuto has frequently been used for several disorders of digestive system.

　Case report:76 years old male had hepatocellular carcinoma and been admitted to our hospital in purpose of an operation of hemihepatectomy. He started to take daikenchuto seven days before the operation. He complained dyspnea on exercise and dry cough on 4^th day post operation. Chest X ray and CT showed diffuse ground grass opacity mainly in lower fields of bilateral lungs. In this stage bacterial pneumonia was suspected, but antibiotics did not effectively improve his condition. The lung opacity gradually got worse. We were consulted to see him and suspected it would be drug-induced lung disorder(DILD)caused by Daikenchuto. After cessation of taking Daikenchuto, his symptoms and lung opacity immediately improved. Later, lymphocyte stimulation test with Daikenchuto was proven to be positive, therefore we diagnosed him as having DILD caused by the medicine.

　Discussion:Although Daikenchuto is the best selling remedy in a field of wakan medicine, there has been a few reports of lung disorder caused by it. When a patient complains any respiratory symptom and diffuse ground grass opacity is observed in chest X-ray or CT after taking Daikenchuto, we should consider it as a cause of drug-induced lung disorder.