Atenolol is used alone or together with other medicines to treat high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. Atenolol is a second-generation β-1–selective adrenergic antagonist that helps lower the heart rate and blood pressure of patients while also decreasing myocardial contractility. Atenolol is approved by the U.S. Food and Drug Administration (FDA) for treating hypertension, angina pectoris, and acute myocardial infarction. Off-label uses of atenolol include the treatment of arrhythmias, migraine prophylaxis, paroxysmal supraventricular tachycardia, alcohol withdrawal, thyrotoxicosis, and ... Atenolol is a beta-blocker that lowers blood pressure and reduces chest pain in people with heart disease. Learn about its dosage, warnings, precautions, and possible side effects from WebMD. Atenolol is a beta blocker used to treat high blood pressure, prevent angina, and improve survival after a heart attack. Learn how to use it, what precautions to follow, what side effects to watch out for, and more.