PROBLEM TO BE SOLVED: To provide a drug having inhibitory activity on ENPP2, which is a different target from those of existing drugs, as a medicament useful for a urinary excretion disorder patient on which the existing drugs have insufficient effects.SOLUTION: The present invention provides a tetrahydrocarboline derivative represented by the general formula (I), a salt thereof or a solvate thereof or a prodrug thereof, and a composition comprising them as an active ingredient.【課題】既存薬では効果が不十分な尿排出障害患者に有用な医薬品として、既存薬とは異なる標的であるＥＮＰＰ２に対して阻害活性を有する薬剤の提供。【解決手段】一般式（Ｉ）で表されるテトラヒドロカルボリン誘導体、その塩もしくはその溶媒和物またはそれらのプロドラッグならびにそれらを有効成分として含有する組成物。【選択図】なし
