There is provided a drug therapy for prevention of glaucoma or prevention or treatment of ocular hypertension, with a potent ocular hypotensive effect and prolonged duration thereof. Disclosed is a combination of (S)-(-)-1-(4-fluoro-5-isoquinolinesulfonyl)-2-methyl-1,4-homopiperazine or a salt thereof, or a solvate thereof, and a prostaglandin for prevention or treatment of glaucoma.本發明係提供眼壓下降作用強力且延長持續時間的青光眼或高眼壓症預防或治療之藥物療法。本發明的組合藥劑，係青光眼預防或治療用，由(S)-(-)-1-(4-氟-5-異喹啉磺醯基)-2-甲基-1,4-高哌或其鹽或該等的溶劑化物、與前列腺素類組合而成。
