CT of Zensartan 40 mg/12.5 mg The two medications in the tablet both aid in the management of hypertension. Telmisartan and chlorthalidone are the two medications that make up Zensartan CT 40mg/12.5mg Tablet. It is typically used when blood pressure cannot be adequately controlled by a single medication. In order to facilitate easier blood flow, telmisartan relaxes and widens your blood vessels. Your blood pressure will drop as a result. Chlorthalidone is a diuretic, or water pill, that lowers blood pressure by increasing urine production. Controlling your blood pressure lowers your risk of heart attack, stroke, and renal issues.