ATENOLOL+HYDROCHLOROTHIAZIDE contains two medicines: atenolol and hydrochlorothiazide which collectively lowers blood pressure. Atenolol is a beta-blocker that works specifically on the heart to slow down the heart rate. Hydrochlorothiazide (diuretic) works by increasing the amount of urine passed out from the kidneys. It effectively reduces excess fluid overload in the body and treats edema (swelling) associated with heart, liver, kidney, or lung disease. This reduces the heart's workload and makes the heart more efficient at pumping blood throughout the body. Thus, collectively, both help lower high blood pressure, reducing heart attack, or stroke chances.