Patient holding a box of propranolol high blood pressure drug. This drug, a beta-adrenoceptor blocking drug (or beta-blocker) is used to lower blood pressure, correct abnormal heart rhythm (arrhythmia) and to treat angina. It is also used in patients who develop heart symptoms in response to stress or tension. Propranolol may also be used to treat overactive thyroid gland, and to prevent attacks of migraine.