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.
