Metoprolol interactions to avoid

In this article:

• Metoprolol-drug interactions
• Other metoprolol interactions
• How to minimize interactions
• When to see a doctor

In this article

• Metoprolol-drug interactions
• Other metoprolol interactions
• How to minimize interactions
• When to see a doctor

Metoprolol is a generic, FDA-approved prescription medication classified as a beta blocker. It’s prescribed to treat hypertension (high blood pressure), angina (chest pain), and heart failure, and to improve survival after a heart attack. Brand names for metoprolol include Lopressor (metoprolol tartrate immediate-release tablets), Toprol XL (metoprolol succinate extended-release tablets), and Kapspargo (metoprolol succinate extended-release capsules).

Like many medications, metoprolol can interact with other drugs, foods, and substances. These interactions can make metoprolol less effective or increase the risk of side effects. Here’s what you need to know to stay safe while taking metoprolol.

Metoprolol-drug interactions

Metoprolol can interact with various prescription and over-the-counter (OTC) medications to varying degrees of severity. Before you take metoprolol, tell your healthcare provider about all the medications you take, including prescription drugs, OTC medicines, vitamins, and supplements. Check with your doctor before starting any new medications while taking metoprolol.

Monoamine oxidase inhibitors (MAOIs)

Drugs in the MAOI class can have an additive effect with beta blockers like metoprolol, which can cause low blood pressure or a slow heartbeat. This can lead to vertigo (a spinning sensation), fainting, or orthostatic hypotension (a drop in blood pressure when you stand up from a sitting or lying down position). If you take an MAOI, your doctor may prescribe a lower dose of metoprolol and monitor you closely. Or, your doctor may choose a different drug to replace the MAOI. Some examples of MAOIs include:

• Azilect (rasagiline)
• Emsam (selegiline)
• Marplan (isocarboxazid)
• Nardil (phenelzine)
• Parnate (tranylcypromine)
• Zyvox (linezolid)

CYP2D6 inhibitors

Metoprolol is metabolized in the body by an enzyme called cytochrome P450 2D6 (CYP2D6). Other medications that inhibit this enzyme can lead to increased levels of metoprolol in the body, which can cause serious side effects. If possible, the combination of interacting drugs should be avoided. If this is not possible, the patient should be closely monitored. Some examples of drugs metabolized by CYP2D6 include:

• Antidepressants such as Paxil (paroxetine), Wellbutrin (bupropion), Prozac (fluoxetine), and Zoloft (sertraline)
• Antipsychotics such as Haldol (haloperidol) or chlorpromazine
• Antiarrhythmics (medicines for an irregular heartbeat) such as quinidine or propafenone
• Antiretrovirals such as Norvir (ritonavir)
• Antihistamines such as Benadryl (diphenhydramine)
• Antimalarial drugs such as Plaquenil (hydroxychloroquine)
• Antifungal medications such as Lamisil (terbinafine)

Drugs that cause bradycardia (slow heart rate)

Beta blockers like metoprolol slow the heart rate, so if metoprolol is combined with another drug that slows the heart rate, there is an increased risk of bradycardia. The patient will be closely monitored if the combination cannot be avoided. Examples of drugs that cause bradycardia include:

• Certain calcium channel blockers, such as verapamil or Cardizem (diltiazem)
• Catapres (clonidine)
• Lanoxin (digoxin)

Alpha-adrenergic blockers

Alpha blockers lower blood pressure, and beta blockers like metoprolol may potentiate the effect. If you take an alpha blocker, consult your healthcare provider for medical advice. 

Different alpha blockers may require different interventions. For example, metoprolol may worsen orthostatic hypotension caused by prazosin. But clonidine has a different interaction—if you are taking both clonidine and metoprolol, and need to stop taking clonidine, you will need to stop taking metoprolol a few days before you stop taking clonidine, to lower the risk of rebound high blood pressure. Examples of alpha blockers include:

• Cardura (doxazosin)
• Catapres (clonidine)
• Minipress (prazosin)

One exception is in people who have an adrenal gland tumor called pheochromocytoma. In these individuals, metoprolol should be used along with an alpha blocker, after the alpha blocker has been started. 

Over-the-counter cough, cold, and flu medicines

Many over-the-counter (OTC) cough, cold, or flu medications contain multiple ingredients that can interfere with heart or blood pressure conditions and interfere with your medication. If you need to take an OTC medication, ask your doctor or pharmacist about the safest options based on your medical conditions. Some examples of drugs that may interact with your condition or medication include:

• Decongestants such as pseudoephedrine or phenylephrine, which can increase blood pressure and/or decrease the effect of metoprolol
• Antihistamines like Benadryl (diphenhydramine), which can increase the risk of metoprolol adverse effects, including low blood pressure and slow heart rate 
• Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, aspirin, or naproxen can make metoprolol less effective

EpiPen (epinephrine)

Epinephrine is a life-saving medicine used for severe allergic reactions. Metoprolol should be used with caution in people who have a history of anaphylactic reactions. These individuals may have more severe reactions to allergens while taking metoprolol—and may also be unresponsive to the usual doses of epinephrine used to treat the allergic reaction. Ask your doctor for medical advice if you have a history of allergic reactions. 

Other metoprolol interactions

In addition to drug-drug interactions, it’s always important to know if your medication interacts with certain foods, drinks, or medical conditions. While metoprolol has no notable food interactions, it is recommended to be taken with or just after a meal. Here are some other interactions and warnings to be aware of. 

Metoprolol and alcohol 

Alcohol and metoprolol can both cause dizziness, lightheadedness, and low blood pressure. Combining them may increase these effects. If you drink alcohol, talk to your provider. People taking Kapspargo should avoid alcohol entirely, as it may cause the drug to release too quickly.

Metoprolol and caffeine 

Caffeine may reduce the effectiveness of beta blockers like metoprolol and raise your heart rate or blood pressure. Small amounts may be okay, depending on your health condition. Ask your provider what’s safe for you.

Metoprolol and certain medical conditions

Before taking metoprolol, tell your physician about all of your medical conditions and medical history, as well as your family history. Metoprolol is not safe for everyone. You should not take this medication if you:

• Are allergic to metoprolol, any beta blocker, or any ingredient in the medication
• Have severe bradycardia (slow heart rate)
• Have second-degree or third-degree heart block (interference with electrical signals that tell your heart when to beat)
• Are in cardiac shock (a life-threatening emergency where the heart cannot pump enough blood and oxygen to the brain and other organs)
• Have decompensated heart failure
• Have sick sinus syndrome (heart rhythm problems caused by the heart’s pacemaker), unless you have a permanent pacemaker
• Have a severe peripheral arterial circulatory disorder (a narrowing or blockage of the vessels that carry blood from the heart to the legs)

Metoprolol may not be appropriate for people with certain other medical conditions. Tell your healthcare provider if you have any medical conditions, including if you are pregnant or breastfeeding.

How to minimize metoprolol interactions

Here are some tips to minimize the risk of metoprolol interactions:

1. Before taking metoprolol, make sure your doctor knows your full medical history and all of the medications you take, so they can screen for drug interactions or other potential problems. While taking metoprolol, do not start any new medications unless approved by your doctor. Keep an updated list of your medications with you. 
2. Metoprolol may cause fatigue and dizziness. Do not drive or operate machinery until you know how metoprolol affects you.
3. Avoid or limit alcohol while taking metoprolol. If you drink alcohol, consult your doctor for medical advice.
4. Know the possible side effects of metoprolol—side effects can worsen if you take an interacting drug. Common side effects include tiredness, dizziness, constipation or diarrhea, depression, shortness of breath, low blood pressure, slow heart rate, and nightmares. Report side effects to your doctor, or get emergency medical help for severe symptoms. You should also get emergency medical help if you experience symptoms of an allergic reaction, such as hives, trouble breathing, or swelling of the face, lips, tongue, or throat. 

When to talk to a healthcare provider about metoprolol interactions

Because there are various potential metoprolol interactions, this article does not provide a complete list. It is important to communicate with your healthcare provider about all of your medical conditions and the medications you take. This will help minimize the risk of interactions and ensure proper management and monitoring.