Cosart-H Tablet is the combination of two medications. It helps to keep high blood pressure under control. Cosart-H Tablet is a mixture of two medications: losartan and hydrochlorothiazide. It is typically used when a single medication is ineffective in managing blood pressure. Losartan works by relaxing and broadening your blood vessels, allowing your blood to flow more easily. This lowers your blood pressure. Hydrochlorothiazide is a diuretic (water pill) that increases urine production, decreasing blood pressure. Controlling your blood pressure reduces your risk of having a heart attack, stroke, or renal problems. To be successful, the medication must be taken on a regular basis, as prescribed. You normally don't notice any direct benefits from taking this prescription, but it works in the long run to keep you healthy.