Metoprolol can interact with several medications, including certain blood pressure drugs, monoamine oxidase inhibitors (MAOIs), digoxin, and others.
Metoprolol is a commonly prescribed beta-blocker medication used to treat high blood pressure, angina (chest pain), heart failure, and other heart-related conditions. It is available in immediate-release forms (under the brand name Lopressor) and extended-release forms (Toprol XL, Kapspargo).
If you are taking metoprolol, it's important to be aware of potential drug interactions. Some interactions can be managed by monitoring for side effects and dose adjustment, while others should be avoided entirely.
This is not a comprehensive list of all drugs that may interact with metoprolol. Before starting treatment, be sure to share your medication history with your healthcare provider, including all over-the-counter (OTC) or prescription drugs and dietary supplements you are taking.
1. Monoamine Oxidase Inhibitors (MAOIs)
Monoamine oxidase inhibitors (MAOIs) are a group of drugs that treat conditions like depression and Parkinson's disease, among others.
Some examples of MAOIs include:
- Azilect (rasagiline)
- Nardil (phenelzine)
- Zyvox (linezolid)
Taking an MAOI with a beta-blocker, such as metoprolol, may cause hypotension (low blood pressure) or significant bradycardia (slow heart rate). This could lead to vertigo (a dizzy, spinning sensation), fainting, or orthostatic hypotension (when your blood pressure drops too quickly upon standing up).
Consult your healthcare provider before combining metoprolol with an MAOI. In many cases, your provider will not even prescribe this combination together. If they do decide to prescribe both drugs, you will need to watch for potential side effects.
2. CYP2D6 Inhibitors
Cytochrome P450 family 2 subfamily D member 6 (CYP2D6) is a type of enzyme that helps process drugs in the body. This enzyme is involved in processing about 25% of commonly prescribed medications.
Drugs that inhibit CYP2D6 can slow down the body's processing of metoprolol, leading to higher levels of metoprolol in the body. This can cause or worsen side effects. Examples of drugs that inhibit CYP2D6 include:
- Paxil (paroxetine)
- Propafenone
- Prozac (fluoxetine)
Generally, your provider will avoid combining any medications with this interaction. If taking metoprolol with a CYP2D6 inhibitor cannot be avoided, you'll need to be closely monitored as this combination can cause additional side effects. Lower starting doses of metoprolol may be needed.
Ask your provider if you are unsure whether any of the medications you take are CYP2D6 inhibitors.
3. Digoxin
Lanoxin (digoxin) is a prescription medication used for heart failure and arrhythmias (abnormal heart rhythms). Similar to metoprolol, digoxin works to slow down your heart rate. If digoxin is combined with a beta-blocker like metoprolol, there is a higher chance of bradycardia.
In some cases, you might be prescribed both metoprolol and digoxin. If your healthcare provider prescribes these medications together, they will closely monitor your heart rate.
4. Certain Blood Pressure Medications
While many people require more than one blood pressure medication to control their blood pressure, some medications may interact with metoprolol:
Calcium Channel Blockers
Like metoprolol, calcium channel blockers, such as Cartia XT or Cardizem (diltiazem) and Verelan (verapamil), slow the heart rate. Therefore, combining any of these medications with metoprolol can increase the risk of bradycardia, which can lead to vertigo, fainting, or orthostatic hypotension.
Clonidine
Clonidine can also slow the heart rate. If you currently take clonidine and need to stop it, your healthcare provider will advise you to follow a specific schedule to help you safely stop treatment.
Norvasc (Amlodipine)
Amlodipine is a blood pressure medication sometimes used with metoprolol to help chest pain and exercise tolerance. However, when combined, these medications can cause blood pressure to drop too low. Also, there may be issues with the heart's ability to pump blood, especially in people with certain medical conditions, including:
- Aortic stenosis (narrowing of the aortic valve, causing the heart to pump poorly)
- Heart arrhythmias
- Left ventricular dysfunction (when the heart's left ventricle does not perform properly)
If you take another blood pressure medication, ask your healthcare provider if it is safe to combine it with metoprolol.
5. Medications That Lower Blood Sugar
Taking beta-blockers, such as metoprolol, may make it harder to recognize when your blood sugar is getting low (hypoglycemia). This is because it slows down your heart rate, so you may not notice some effects of hypoglycemia, like tachycardia (a fast heart rate).
Because of this effect, there may be an increased risk for severe or prolonged low blood sugar. The risk is higher in people with diabetes as well as anyone who is fasting or sick with vomiting.
If you use insulin or take medications that lower blood sugar, you should monitor your blood sugar as directed by your healthcare provider. Know what to do if your blood sugar is too low and when to get emergency medical help.
Examples of medicines that lower blood sugar include:
- Insulin, such as Lantus or Novolog
- Januvia (sitagliptin)
- Metformin
- Ozempic (semaglutide)
You may want to ask your healthcare provider about a prescription for Baqsimi (glucagon), which is an emergency treatment for severely low blood sugar.
A Word From Verywell
Many drug interactions with metoprolol can lead to a slowed heart rate, which may cause dizziness, light-headedness, or fainting. Be sure to notify your prescriber if you experience any of these side effects, as they may indicate that your dose needs adjustment. Consult your healthcare provider or pharmacist to understand how this medication might interact with anything else you're taking.
— MARY CHOY, PHARMD, MEDICAL EXPERT BOARD
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6. Over-the-Counter Pain and Cold Medicines
When you have pain, a cough, or a cold, it is tempting t'o reach for an over-the-counter (OTC) treatment. However, not all OTC treatments are recommended if you have high blood pressure and/or take metoprolol.
Examples include:
Benadryl (Diphenhydramine)
Diphenhydramine, the active ingredient in Benadryl and also an ingredient in some combination cough and cold products, is a CYP2D6 inhibitor. This means it can increase the risk of side effects, including low blood pressure and a slowed heart rate, when combined with metoprolol.
Sudafed (Pseudoephedrine)
Pseudoephedrine is an oral decongestant found in Sudafed and other products. Pseudoephedrine can increase blood pressure and heart rate, which can counteract the effects of metoprolol. Depending on your blood pressure control, your healthcare provider may advise you to avoid pseudoephedrine (and instead try a nasal spray, neti pot, and/or home remedies), or only use pseudoephedrine for a short time.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
NSAIDs, like Advil or Motrin (ibuprofen) or Aleve (naproxen), which are available in both prescription and OTC formulations, are commonly used for pain, inflammation (swelling), and fever. If you take metoprolol along with an NSAID, metoprolol may not work as well to lower your blood pressure. Your healthcare provider may recommend that you monitor your blood pressure closely if you mix these medicines.
If you take metoprolol, always check with your pharmacist or healthcare provider before using any OTC drugs.
7. EpiPen (Epinephrine)
Epinephrine is commonly used to treat life-threatening allergic reactions. If you have a history of severe allergic reactions, there may be a possibility that you may not respond as well to the usual doses of epinephrine used for an allergic reaction while taking metoprolol.
However, some research has found that beta-blockers should not significantly affect the amount of epinephrine needed to treat an allergic reaction. Check with your healthcare provider for medical advice.
8. Alcohol
Most metoprolol products do not have a specific warning regarding alcohol, except Kapspargo (metoprolol succinate). Kapspargo contains a specific formulation of metoprolol succinate that is released in a controlled manner over 24 hours.
When Kapspargo is combined with alcohol, the metoprolol is released faster, which can increase the risk of side effects of Kapspargo. If you take Kapspargo, you should avoid alcohol.
Although other metoprolol drugs do not chemically interact with alcohol, you should check with your healthcare provider regarding alcohol consumption. Studies have found that alcohol is associated with increased blood pressure, especially if you drink a lot of it.
Does Metoprolol Interact With Grapefruit?
Grapefruit and grapefruit juice interact with many drugs due to their effect on an enzyme called CYP3A4. Because of this interaction, people who take certain medications, such as some statins for high cholesterol and some antibiotics, are advised to avoid grapefruit juice.
Metoprolol does not interact with grapefruit juice. However, people who take metoprolol may take other drugs that interact with grapefruit, such as cholesterol medication. Check with your healthcare provider regarding any dietary restrictions.
Summary
Metoprolol is a commonly prescribed beta-blocker for conditions like high blood pressure, chest pain, and heart failure. Important interactions to be aware of when taking metoprolol include monoamine oxidase inhibitors (MAOIs), CYP2D6 inhibitors, digoxin, certain blood pressure medications, and insulin or other medicines that lower blood sugar.
Certain OTC medicines can affect how well metoprolol works or may increase side effects. If you take Kapspargo, you should avoid alcohol. However, even if you take another form of metoprolol, you should check with your healthcare provider about alcohol consumption. Be sure your healthcare provider knows about all the medications you take, including prescription and OTC drugs, vitamins, and supplements.
