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Developed more than 50 years ago, propranolol is a prescription drug used for everything from treating high blood pressure to preventing migraine attacks.
Even though it’s an effective drug for treating a number of heart-related conditions, propranolol can also pose potential dangers. For example, it can improve a patient’s survival rate after a heart attack, but if taken improperly, it could also cause a heart attack.
The U.S. Food and Drug Administration (FDA) has given propranolol a black box warning, meaning it has the potential to cause serious and life-threatening side effects. Stopping this medication suddenly can result in chest pain or even a heart attack (FDA, 2010).
It’s important to discuss the risks associated with propranolol with a healthcare professional before starting treatment. Here’s what you need to know about the medication’s side effects, drug interactions, and who should avoid it.
What are the side effects of propranolol?
While propranolol is safe and effective for many people, there are some important warnings to be aware of. Propranolol carries a black box warning—the most severe type issued by the FDA. Do not stop taking propranolol suddenly as this can trigger a heart attack (FDA, 2010). If you would like to stop taking this medication, it’s important to first consult a healthcare professional to get guidance about how to stop it safely.
There are also risk factors that can heighten the chance of adverse reactions from propranolol, like if you have an underlying health condition or are on multiple medications. Some common side effects include: cough, difficulty breathing, dry eyes, dizziness, fatigue, difficulty sleeping, skin rash, itching, tingling hands, digestive problems, and weight gain.
Past studies have found that beta blockers may be linked to depression or changes in mood, although the scientific research on this is mixed (Head, 2016). Beta blockers may also affect sexual function (most notably causing erectile dysfunction for some people) (Nicolai, 2014). If you find that this medication affects your sex life, speak with your healthcare provider. There are alternative treatments that may alleviate this side effect while still controlling your blood pressure.
Propranolol can also cause serious and potentially life-threatening side effects. This is not the full list, but here some of the most important adverse effects of propranolol (FDA, 2010):
- Slow heartbeat (bradycardia): Propranolol slows down your heart rate, but in some cases, it may cause your heart rate to drop too low, which can be dangerous or even life-threatening. Symptoms can include chest pain, dizziness, fatigue, and fainting.
- Low blood pressure (hypotension): Since propranolol is meant to lower blood pressure, sometimes it can lower blood pressure too far, a condition called hypotension—or excessively low blood pressure. Symptoms may include blurred vision, confusion, dizziness, fatigue, and shallow breathing.
- Worsening of lung disease: Propranolol can make lung conditions like asthma or emphysema worse. People with a history of respiratory conditions should avoid taking this drug.
- Masking of low blood sugar: If you have diabetes, use caution when taking propranolol. This medication can mask symptoms of low blood sugar (hypoglycemia)—such as anxiety, shakiness, and heart palpitations—which, if left untreated, can lead to life-threatening complications or even death. Propranolol has also been found to decrease blood sugar levels in people without diabetes.
- Worsening of heart failure: Propranolol can exacerbate heart failure in individuals already living with the condition.
- Masking signs of hyperthyroidism: While propranolol is sometimes prescribed off-label to treat thyroid storm caused by hyperthyroidism, the drug can also mask symptoms of an overactive thyroid.
- Severe allergic reactions: People may experience allergic reactions including difficulty breathing, hives, and swelling of the face and throat while taking propranolol. It can also cause rare, severe skin rashes like Stevens-Johnson syndrome or toxic epidermal necrolysis.
Certain people—including pregnant women and people with conditions like heart failure or lung disease—should use caution taking propranolol or avoid it altogether.
Beta blockers: how they’re used to treat heart conditions
What is propranolol?
Propranolol, also available under the brand name Inderal, falls into a class of drugs called beta blockers, which are used to help lower blood pressure. The medication was developed in the 1960s, and was the first beta blocker invented to treat irregular heartbeats and chest pain from cardiovascular disease (Srinivasan, 2019).
Beta blockers like propranolol are also used for other heart-related issues, such as alleviating angina (chest pain associated with reduced blood flow to the heart muscle) and improving survival rates after a heart attack (AHA, 2017).
Healthcare professionals and researchers have also found propranolol to be effective in the treatment of a range of other conditions, including migraines, essential tremor, atrial fibrillation (“a-fib”), and performance anxiety. Here are the main uses of propranolol (FDA, 2010):
- High blood pressure (hypertension): Beta blockers like propranolol help manage hypertension by blocking adrenaline, a hormone that makes your heart beat harder. Blocking this hormone allows your heart to beat with less force. Beta blockers also relax the blood vessels (the equivalent of adding lanes to a highway), which reduces congestion and lowers blood pressure. Propranolol is frequently taken alongside other drugs—like ACE inhibitors, calcium channel blockers, or diuretics—to manage high blood pressure.
- Chest pain (angina pectoris): Chest pain that results from reduced blood flow to the heart muscle is called angina. Propranolol helps alleviate angina pectoris, or stable angina, and is especially beneficial for angina that occurs during physical activity (UpToDate, 2020).
- Atrial fibrillation (afib): Beta blockers slow down your heart rate, which is beneficial for people living with atrial fibrillation, a condition characterized by rapid and irregular heart rhythms.
- Heart attack (myocardial infarction): Propranolol is frequently prescribed to people who have had a heart attack as studies have shown that it improves long term survival (JAMA, 1981).
- Migraine: One of the most popular first-line drugs for migraine prevention is propranolol (Ha, 2019). Why propranolol helps prevent migraine attacks isn’t fully understood, but it’s been proven to reduce the severity and frequency of attacks.
- Essential tremor: Propranolol helps decrease the visibility of shaking from essential tremor, a condition that causes involuntary shaking in the body, especially in the hands (NIH, 2020).
- Performance anxiety and social phobias: Because beta blockers help slow heart rate, these drugs are commonly prescribed off-label (meaning for something other than its FDA-approved use) for social anxiety. If taken before a performance on stage, for example, propranolol can help reduce symptoms associated with stage fright, such as sweating and heart palpitations.
- Other uses include a heart condition called hypertrophic obstructive cardiomyopathy (HOCM), blood pressure changes associated with rare endocrine tumors called pheochromocytomas, and a rare condition called thyroid storm, which is characterized by a sudden elevation in thyroid hormones.
Propranolol for anxiety: does it work?
There are many drugs propranolol could interact with. Here are the main ones to be aware of (FDA, 2010):
- Drugs affecting the cytochrome P-450 system: Propranolol may change the way your body handles medications processed by a system in your liver.
- Antiarrhythmics: The risk for side effects increase when combining propranolol with antiarrhythmic drugs like amiodarone, digoxin, lidocaine, propafenone, and quinine.
- Calcium channel blockers: Propranolol increases the chance of side effects if taken alongside calcium channel blockers, such as diltiazem, nicardipine, nisoldipine, nifedipine, and verapamil.
- Migraine medication: Levels of zolmitriptan or rizatriptan could increase when used at the same time as propranolol.
- Blood pressure drugs: Beta blockers can enhance the effects of low blood pressure medication, including doxazosin, enalapril, lisinopril, prazosin, and terazosin.
- Diazepam: The effects of diazepam (a medication used for anxiety) are heightened if used at the same time as propranolol, increasing the risk of side effects.
- High cholesterol medication: Cholesterol medications like cholestyramine, colestipol, lovastatin, and pravastatin can impact the concentration levels of propranolol the body.
- Monoamine oxidase inhibitors (MAOIs): The risk of side effects could increase if MAOIs—which are commonly used to treat depression—are taken alongside propranolol. Types of MAOIs include: isocarboxazid, phenelzine, selegiline, and tranylcypromine.
- Warfarin: Combining propranolol and warfarin, a blood thinner, can increase the concentration of warfarin in the body.
- Non-steroidal anti-inflammatory drugs (NSAIDs): NSAIDs like ibuprofen and indomethacin, for example, may decrease how effective propranolol is.
- Alcohol: Alcohol also increases propranolol levels in the blood, which could enhance the chance of adverse reactions.
This does not contain the whole list of potential drug interactions with propranolol. Talk to a healthcare professional about any other health issues or medications you’re taking before starting treatment with propranolol.
What is propranolol used for?
Adding lifestyle changes into the mix—like exercising, eating a healthy diet, and quitting smoking—not only reduces the risk of side effects when taking propranolol, but it also improves your overall health (CDC, 2020).
- American Heart Association (AHA). (2017). How do beta blocker drugs affect exercise? Retrieved Oct. 25, 2020 from https://www.heart.org/en/health-topics/consumer-healthcare/medication-information/how-do-beta-blocker-drugs-affect-exercise
- Centers for Disease Control and Prevention (CDC). (2020). How You Can Prevent Chronic Diseases. Retrieved on Oct. 22, 2020 from https://www.cdc.gov/chronicdisease/about/prevent/index.htm
- DailyMed. (2019). Propranolol hydrochloride capsule. Retrieved Oct. 20, 2020 from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8efc9fc6-6db0-43c9-892b-7423a9ba679f
- Ha, H. & Gonzalez, A. (2019). Migraine Headache Prophylaxis. American Family Physician, 99(1), 17-24. Retrieved from https://www.aafp.org/pubs/afp/issues/2019/0101/p17.html
- Head, G. A. (2016). Impact of Cardiac Medications on Mood. Handbook of Psychocardiology. Retrieved from https://link.springer.com/referenceworkentry/10.1007%2F978-981-287-206-7_65
- National Institute of Neurological Disorders and Stroke (NIH). (2020). Tremor fact sheet. Retrieved from https://www.ninds.nih.gov/tremor-fact-sheet
- Nicolai, M. P., Liem, S. S., Both, S., Pelger, R. C., Putter, H., Schalij, M. J., et al. (2014). A review of the positive and negative effects of cardiovascular drugs on sexual function: a proposed table for use in clinical practice. Netherlands Heart Journal, 22(1). doi: 10.1007/s12471-013-0482-z. Retrieved from https://link.springer.com/article/10.1007%2Fs12471-013-0482-z
- Srinivasan, A. V. (2019). Propranolol: A 50-Year Perspective. Annals of Indian Academy of Neurology, 22(1): 21-26. https://dx.doi.org/10.4103%2Faian.AIAN_201_18. Retrieved from https://www.annalsofian.org/article.asp?issn=0972-2327;year=2019;volume=22;issue=1;spage=21;epage=26;aulast=Srinivasan
- The β-Blocker Heart Attack Trial (JAMA). (1981). JAMA, 246(18): 2073-2074. doi:10.1001/jama.1981.03320180063037. Retrieved from https://jamanetwork.com/journals/jama/article-abstract/363981
- UpToDate. (2020). Patient education: Medications for angina (Beyond the Basics). Retrieved Oct. 25, 2020 from https://www.uptodate.com/contents/medications-for-angina-beyond-the-basics
- U. S. Food and Drug Administration (FDA). (2010). Inderal (propranolol hydrochloride) tablets. Retrieved on Oct. 20, 2020 from https://www.accessdata.fda.gov/drugsatfda_docs/label/2011/016418s080,016762s017,017683s008lbl.pdf
Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.