Beta blockers, also known as beta-adrenergic blocking agents, are a class of medicines that lower blood pressure by blocking the effects of the hormone epinephrine, also known as adrenaline. They cause the heart to beat more slowly and with less force, which lowers blood pressure. Beta blockers also help widen veins and arteries to improve blood flow. Beta blockers are mainly used to treat heart and circulatory conditions, including high blood pressure, irregular heart rhythms, chest pain (angina), heart attacks, heart failure, and aortic dissection. They are also used to prevent, treat, or improve symptoms in other conditions, such as migraines, some types of tremors, and glaucoma. Beta blockers are available in several types, and the best one for an individual depends on their health conditions. Some examples of beta blockers taken by mouth include acebutolol, atenolol, bisoprolol, metoprolol, nadolol, nebivolol, and propranolol. Beta blockers are prescription-only medicines and can only be prescribed by a GP or another suitably qualified healthcare professional. Beta blockers are not suitable for everyone, and it is important to tell a doctor about any other conditions before taking them. Common side effects of beta blockers include tiredness, cold hands and feet, slow heartbeat, and dizziness.