Diovan HCT is a prescription medication used to treat high blood pressure. It is a single product containing 2 medications: valsartan and hydrochlorothiazide. Valsartan is in a class of medications called angiotensin II receptor antagonists. It works by blocking the action of certain natural substances that tighten the blood vessels, allowing the blood to flow more smoothly and the heart to pump more efficiently. Hydrochlorothiazide is in a class of medications called diuretics ('water pills'). It works by causing the kidneys to get rid of unneeded water and salt from the body into the...