What are the most common side effects of propranolol? The most common side effects of propranolol are listed below. Tell your healthcare provider if you have any of these side. Some conditions may become worse when the medicine is stopped suddenly, which can be dangerous. Propranolol will add to the effects of alcohol and other central nervous system (CNS) depressants. CNS depressants are medicines that slow down the nervous system and may cause drowsiness. Propranolol is a beta-blocker used to treat high blood pressure, irregular heartbeats, shaking (tremors), and other conditions. It is used after a heart attack to improve the chance of survival. It is also used to prevent migraine headaches and chest pain (angina). This may increase your risk of side effects, such as chest pain and heart attack. If you no longer need to take this medication, your care team will lower the dose slowly over time to decrease the risk of side effects. NHS medicines information on propranolol – what it's used for, side effects, dosage and who can take it. Propranolol appears in the blood after 30 minutes and has a maximum effect between 60 and 90 minutes when taken orally. [11][15] Common side effects include nausea, abdominal pain, and constipation. [11] It may worsen the symptoms of asthma. [11] Common propranolol side effects may include: runny or stuffy nose, cough, sore throat, hoarse voice. Serious side effects. Read on to learn the common and rare side effects for propranolol, and when to reach out to your healthcare team for further guidance. NHS medicines information on side effects of propranolol and what you can do to cope. Learn about the side effects of propranolol, from common to rare, for consumers and healthcare professionals.