This medication is used to treat high blood pressure (hypertension). Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems. This product contains 2 medications: metoprolol and hydrochlorothiazide. Metoprolol belongs to a class of drugs known as beta blockers. It works by keeping certain natural chemicals such as epinephrine from acting on the heart and blood vessels. This effect lowers the heart rate, blood pressure, and strain on the heart. Hydrochlorothiazide is a "water pill" (diuretic) and causes your body to get rid of extra salt and water. This effect may increase the amount of urine you make when you first start the medication.