A microneedle device of the present invention comprises a substrate, microneedles disposed on the substrate, and a coating formed on the microneedles, wherein the coating comprising dexmedetomidine or a pharmaceutically acceptable salt thereof and isoproterenol or a pharmaceutically acceptable salt thereof. Using said microneedle device, a fast increase rate of dexmedetomidine concentration in plasma after application of the microneedle device is achieved.
