How Do You Use Them?

Propranolol

The brand-name drug Inderal has been discontinued, but the generic propranolol immediate-release (IR) is still available. The U.S. Food and Drug Administration (FDA) has approved IR propranolol for:

• Hypertension (high blood pressure)
• Angina (chest pain) to help decrease the frequency of symptoms and increase exercise tolerance
• Atrial fibrillation to control the ventricular rate
• Improving survival after a myocardial infarction (heart attack)
• Migraine prevention
• Management of essential tremor
• Hypertrophic subaortic stenosis, a medical condition in which the heart muscle becomes abnormally thickened
• Pheochromocytoma, which is a rare type of tumor that develops in an adrenal gland

Propranolol extended-release (ER) is available under the brand names Inderal LA and Innopran XL. The FDA has approved propranolol ER for:

• Hypertension
• Angina
• Migraine prevention
• Hypertrophic subaortic stenosis

Propranolol may also be taken off-label (for a non-FDA-approved use) for various indications, such as:

Metoprolol

Metoprolol IR, also known as metoprolol tartrate, is available under the brand name Lopressor. It is also available as a generic. The FDA has approved it for the following conditions:

• Hypertension
• Angina
• To improve survival after a heart attack

Metoprolol ER, also known as metoprolol succinate ER, is available under the brand name Toprol XL (ER tablet) and Kapspargo Sprinkle (ER capsule), as well as generic ER tablets. The FDA has approved it for the following conditions:

• Hypertension
• Angina
• Heart failure (to lower the risk of heart-related death and heart failure hospitalizations)

Metoprolol may also be prescribed off-label for uses such as:

• Atrial fibrillation
• Atrial flutter
• Tremor
• Migraine prevention

How Do They Work?

Propranolol and metoprolol are beta-blockers. Beta-blockers block the action of epinephrine (also known as adrenaline), a substance produced in the body that can increase heart rate and blood pressure. By blocking epinephrine, beta-blockers reduce heart muscle contractions and lower the heart’s demand for oxygen.

Beta-blockers are further classified as selective and nonselective based on the beta receptors they target. Beta receptors are a group of proteins found in different parts of the body, such as the heart. Propranolol is a nonselective beta-blocker and metoprolol is a selective beta-blocker:

• Selective beta-blocker: This type of beta-blocker primarily targets beta-1 receptors, which are found in the heart. This is why selective beta-blockers are mostly taken for heart conditions.
• Nonselective beta-blocker: This type of beta-blocker targets both beta-1 and beta-2 receptors. Beta-2 receptors are found in the lungs and other parts of the body, like the brain. Nonselective beta-blockers can be taken for heart conditions but also for other types of conditions, such as migraines.

Although metoprolol is considered a selective beta-blocker, it may also work on beta receptors in other parts of the body when taken at higher doses.

Side Effects and Safety

Side Effects

Common side effects of both propranolol and metoprolol include the following:

• Dizziness
• Lightheadedness
• Tiredness
• Diarrhea
• Constipation

Some other common side effects of metoprolol include:

• Depression
• Nausea and vomiting
• Dry mouth
• Gastrointestinal issues, such as stomach pain, heartburn, gas, or bloating
• Rash or itching
• Cold hands and feet
• Runny nose

This is not a full list of side effects, and others may occur. Consult your healthcare provider for more information about the side effects of both drugs.

Drug Interactions

Before taking propranolol or metoprolol, tell your healthcare provider about all other medications you are taking, including prescription and over-the-counter (OTC) drugs, vitamins, and supplements. Your provider can check for drug interactions.

Though each drug may have specific interactions, below are some examples of drug interactions that apply to both propranolol and metoprolol.

• Quinidine
• Prozac (fluoxetine)
• Paxil (paroxetine)
• Propafenone 
• Clonidine
• Cardizem (diltiazem)
• Verelan (verapamil)

Other Precautions

Both drugs have several contraindications, or reasons that someone should not use the drug. You should not take propranolol or metoprolol if:

• You are allergic to any ingredient in the medicine.
• You are having a medical emergency called cardiogenic shock (when the heart is unable to pump enough blood).
• You have certain types of heart problems, including sinus bradycardia (a slow heart rate) or certain types of heart block (problems with the heart’s electrical signals).
• You have asthma.

Before taking propranolol or metoprolol, tell your healthcare provider about your medical conditions and history. Some other precautions include but are not limited to:

• Beta-blockers may mask symptoms of hypoglycemia (low blood sugar), especially in people with diabetes who use insulin. Talk to your healthcare provider about the risks versus benefits of beta-blockers if you have diabetes.
• People with lung conditions, such as asthma or chronic obstructive pulmonary disease (COPD), typically should not take beta-blockers. However, recent studies have found that selective beta-blockers may not be associated with a significantly increased risk of asthma exacerbation. In some cases, healthcare providers may determine that the benefits of a beta-blocker outweigh the risks. In this case, they would closely monitor you.
• If you stop taking a beta-blocker, your healthcare provider will instruct you on how to gradually taper your dose. Abruptly stopping a beta-blocker can cause certain problems, such as worsening chest pain or heart attack.

Which One Should You Take?

Only your healthcare provider can determine which medication is best for you, considering various factors such as your health conditions, medical and family history, and other medications you take.

In some cases, one drug may be preferred over the other based on its FDA-approved uses. For example, propranolol is commonly taken to prevent migraines, while metoprolol is not FDA-approved for this purpose (although it may be taken off-label). Conversely, metoprolol ER is approved for heart failure, while propranolol is not.

Both drugs are considered safe and effective and are available in multiple doses and formulations (IR and ER) for precise dosing. Your healthcare provider will also consider side effects, dosing frequency, and how well each medication aligns with your overall treatment plan.

Summary

Propranolol and metoprolol are both beta-blockers taken to treat heart conditions, but they differ in selectivity and uses.

Propranolol is nonselective, meaning it blocks both beta-1 and beta-2 receptors. This makes it useful for migraine prevention and essential tremor as well as certain heart conditions. Metoprolol, a selective beta blocker, primarily targets the heart and is commonly taken for high blood pressure, angina, and heart failure.

Both drugs have similar side effects, including dizziness and tiredness. Consult your healthcare provider for medical advice on the best treatment for you.