NSAID起因性小腸病変

NSAID Induced Small Intestinal Lesions

要旨　小腸内視鏡の進歩は，非ステロイド性抗炎症薬（NSAID）により，胃のみならず小腸に多彩な病変が高頻度に起こることを明らかにした．特に通常型NSAIDでは2週間で50％を超える服用者に小腸粘膜障害が現れる．NSAID起因性小腸粘膜傷害には粘膜障害と絨毛欠損という異なる2種類の形態があり，小腸粘膜傷害の起因には複数の因子が関与している．NSAID起因性胃粘膜傷害に対して予防法・治療法が確立したため，NSAID服用者の下部消化管傷害に対する対応の確立が急務となっている．本邦を中心として，NSAID起因性小腸粘膜傷害に対する予防薬・治療薬の候補を探すため二重盲検無作為化比較試験を含む複数の試験が小規模ながら行われた．今後は見込みのある薬に対して，より大規模な臨床試験が望まれる．

　Capsule endoscopy and balloon endoscopy, advanced modalities that allow full investigation of the entire small intestine, have revealed that NSAID（nonsteroidal anti-inflammatory drug）can cause a variety of abnormalities in the small intestine. Recently, several reports show that NSAID included acetylsalicylic acid can induce small intestinal injuries with high prevalence in patients taking these drugs. These reports have shown that the preventive effect of PPIs（proton pump inhibitors）does not extend to the small intestine, suggesting that concomitant therapy may be required to prevent small intestinal side effects associated with NSAID use. Recently, several randomized controlled trials used capsule endoscopy to evaluate the preventive effect of mucoprotective drugs against NSAID-induced small intestinal injury. However, those studies were limited to a small number of subjects and tested only short-term NSAID treatment. Therefore, further extensive studies are clearly required to ascertain the beneficial effect of these drugs.