低用量aspirinによる胃粘膜傷害

Gastric Mucosal Injuries by Administration of Low-dose Aspirin

要旨　低用量aspirinは心筋梗塞，脳梗塞などの動脈血栓性疾患の発症予防として用いられている．低用量aspirinの副作用として，胃および十二指腸における潰瘍・びらんの発生が，頻度も高く問題となっている．自覚症状を欠くため，消化管出血などが出現して初めて診断されることが多い．H. pylori陰性の若年健常人ボランティアを対象とした低用量aspirinによる胃粘膜傷害の臨床研究を行った．低用量aspirin単回投与後2時間で，胃粘膜には出血点が高率に出現した．低用量aspirin 1週間継続投与によって発赤，出血点，びらんが有意に増加したが，腹部症状には変化がなかった．低用量aspirinとloxoprofenを併用すると発赤，出血点，びらんなどの胃粘膜傷害が倍近くに増加した．臨床において低用量aspirinによる胃粘膜傷害に対しては内視鏡検査が有用であった．

　Low-dose aspirin is clinically used for prevention of cardiovascular and cerebrovascular events. A problem arises in that low-dose aspirin treatment sometimes causes ulcers and erosions in the stomach and duodenum. Patients are often diagnosed as suffering hemorrhage from the gastrointestinal tract without any abdominal symptoms. A few clinical trials were performed in young healthy volunteers to evaluate low-dose aspirin-induced gastric injury. One-time administration of aspirin at 81 mg induced endoscopically bleeding spots in a high proportion of volunteers. Administration of aspirin at 81 mg for 7 consecutive days induced significant erythema, bleeding spots, and erosions. However, there was no change in abdominal symptoms. Volunteers with concomitant administration of aspirin and loxoprofen had more serious gastric injuries. Endoscopic examination is necessary to screen low-dose aspirin users for gastric mucosal injuries.