PROBLEM TO BE SOLVED: To provide a pharmaceutical composition in which a side effect is few and that is useful for treating and/or preventing glaucoma, comprising a specific sulfonamide compound.SOLUTION: Provided is a pharmaceutical composition comprising a pyridylamino acetic acid compound represented by general formula (1) or a pharmacologically acceptable salt thereof as an active ingredient. In the formula, R, Rand Reach independently represent a hydrogen atom or a 1-6C alkyl group; Y represents a dicyclic heteroaromatic ring group or the like; and Z represents an aromatic ring group or a 5-membered or 6-membered ring heteroaromatic group which may be substituted by a group chosen from the group consisting of a halogen atom, a 1-6C alkyl group, a 1-6C halogenoalkyl group, a 1-6C alkoxy group or a 1-6C halogenoalkoxy group.【課題】副作用が少なく、緑内障の治療及び/又は予防に有用な特定のスルホンアミド化合物を含有する医薬組成物を提供。【解決手段】一般式(1)[式中、R1、R2及びR3は、各々独立して、水素原子又はC1-C6アルキル基を示し、Yは、2環式複素芳香環基等を示し、Zは、ハロゲン原子、C1-C6アルキル基、ハロゲノC1-C6アルキル基、C1-C6アルコキシ基及びハロゲノC1-C6アルコキシ基よりなる群から選択される基で置換されていてもよい芳香環基若しくは5乃至6員環複素芳香環基を示す]で表されるピリジルアミノ酢酸化合物又はその薬理上許容される塩を有効成分として含有する医薬組成物。【選択図】なし