Preventive or therapeutic agent for pain associated with herpes zoster in acute phase

摘要

A P2X₄ receptor antagonist such as paroxetine, a diazepinedione derivative having the following formula (IX) is used as an agent for preventing or treating zoster-associated pain in acute phase:; wherein R¹ is hydrogen, a C_1-8 alkyl group, or the like;each of R² and R³ is hydrogen, a C_1-8 alkyl group, or the like;each of R⁴ and R⁵ is hydrogen or the like; andW is a five-membered or six-membered heterocyclic ring optionally having one or more substituents and comprising one to four nitrogen atoms as the members of the ring.