Micardis HCT Hydrochlorothiazide, HCTZ; Telmisartan tablets What do telmisartan-hydrochlorothiazide tablets do?TELMISARTAN-HYDROCHLOROTHIAZIDE (Micardis(R) HCT) is a combination of two drugs used to lower blood pressure. Telmisartan controls high blood pressure (hypertension) by relaxing blood vessels. Hydrochlorothiazide is a diuretic. High blood pressure can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. This medicine does not cure high blood pressure. By lowering blood pressure, telmisartan-hydrochlorothiazide can help reduce your risk of having damage to your kidneys, heart, or other organs.