PROBLEM TO BE SOLVED: To provide a novel therapeutic agent for persistent somatoform pain disorder.SOLUTION: The invention provides a chronic pain therapeutic agent containing as an active ingredient aripiprazole (7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl] butoxy}-3,4-dihydrocarbostyril or 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl] butoxy}-3,4-dihydro-2(1H)-quinolinone) which is an atypical antipsychotic agent useful for the therapy of schizophrenia and an acid addition salt thereof or a solvate thereof. The invention also provides an administration method of a chronic pain therapeutic agent, in which the dosage of aripiprazole to a patient is around 0.05-10 mg/kg body weight/day.
CHRONIC PAIN THERAPEUTIC AGENT