PROBLEM TO BE SOLVED: To provide a novel prophylactic or therapeutic agent for osteoarthritis capable of suppressing the progression of osteoarthritis, and a pharmaceutical composition containing the prophylactic or therapeutic agent for osteoarthritis. A preventive or therapeutic agent for osteoarthritis contains a G protein-coupled receptor kinase 5 inhibitor as an active ingredient. The pharmaceutical composition for preventing or treating osteoarthritis comprises the prophylactic or therapeutic agent for osteoarthritis and a pharmaceutically acceptable carrier. [Selection diagram] None【課題】変形性関節症の進行を抑制できる新規の変形性関節症の予防又は治療剤及び前記変形性関節症の予防又は治療剤を含む医薬組成物を提供する。【解決手段】変形性関節症の予防又は治療剤は、Ｇタンパク質共役型受容体キナーゼ５阻害剤を有効成分として含有する。変形性関節症の予防又は治療用医薬組成物は、前記変形性関節症の予防又は治療剤、及び薬学的に許容可能な担体を含む。【選択図】なし
