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Metoprolol-succinate-ER: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Oct 17, 2022.

1. How it works

  • Metoprolol succinate is a heart medication that works by blocking the effects of epinephrine on beta-1 receptors within the heart tissue, causing the heart to pump more slowly and with less force. At high doses, metoprolol succinate also blocks beta-2 receptors within the lungs and breathing tubes (which may affect breathing).
  • Metoprolol is available as two different salts: metoprolol tartrate and metoprolol succinate. These two salts are not interchangeable because they have different dosages, durations of action, and indications for use.
  • Metoprolol succinate belongs to the class of drugs known as beta-blockers.

2. Upsides

  • Lowers blood pressure and relieves symptoms of angina in people with heart disease.
  • Available as an extended-release (ER) tablet which means it can be dosed once a day. ER forms may be beneficial in people with certain types of heart failure.
  • Classified as a "selective" beta-blocker meaning it is less likely than nonselective beta-blockers to affect breathing and insulin response, particularly at lower dosages.
  • Generic metoprolol succinate is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Heart rate slowing, depression, diarrhea, skin rash, and shortness of breath. Side effects are similar for both metoprolol succinate and metoprolol tartrate because they both contain the same active drug, metoprolol.
  • Dry eyes; blurred vision; dizziness, particularly when rising from sitting to a standing position; fatigue; nightmares, slow heartbeat, and sweating are common.
  • Less common side effects include facial and limb swelling, headache, visual disturbances, and tingling of the hands or feet.
  • Avoid abrupt discontinuation; stopping metoprolol (both succinate and tartrate) suddenly can exacerbate angina and may increase the risk of a heart attack. Reduce dosage gradually over a few weeks as instructed by your doctor.
  • May interfere slightly with laboratory cholesterol results.
  • 8% of the Caucasian population and approximately 2% of other populations have a reduced ability to metabolize metoprolol; dosage may need reducing.
  • May not be suitable for some people including those with heart block greater than 1st degree, pheochromocytoma, poor circulation, sick sinus syndrome, a thyroid disorder, overt or decompensated heart failure, or under the age of 18.
  • Should be used with caution in people with pre-existing respiratory disease.
  • Should not be used to prevent heart attacks.
  • May decrease symptoms of hypoglycemia (low blood sugar levels), such as a fast heart rate, palpitations, tremors, and feelings of anxiety, and potentiate the hypoglycemic effects of insulin.
  • May also mask signs of hyperthyroidism (such as a fast heart rate). May precipitate a thyroid storm if abruptly stopped.
  • May interact with some other medications including antidepressants, antipsychotics, ergot alkaloids, or some other blood pressure medications.
  • There are no adequate and controlled studies using metoprolol in pregnant women. Animal studies have reported an increased risk of spontaneous abortion and decreased neonatal survival in rats but no teratogenicity. It is unknown how animal studies translate to humans. Only use if benefits outweigh risks. Metoprolol is excreted in breast milk in very small amounts (approximately 1mg of metoprolol per 1 liter of breast milk daily).

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Metoprolol succinate ER is a selective beta-blocker that is used to lower blood pressure or relieve symptoms of angina in people with heart disease. It may also be used in the treatment of certain types of heart failure. Metoprolol succinate is not interchangeable with metoprolol tartrate. Metoprolol succinate should not be stopped abruptly.

5. Tips

  • Take tablets at the same time each day.
  • Can be taken once daily.
  • Metoprolol succinate tablets can be taken with or without food.
  • Extended-release tablets may be scored or divided; however, do not crush or chew, swallow whole.
  • Report any shortness of breath or facial swelling immediately to your doctor.
  • Also, talk to your doctor if you develop a very slow heartbeat or cold feeling in your hands or feet.
  • If you are diabetic, talk to your doctor about the possibility that metoprolol may reduce symptoms of hypoglycemia.
  • Talk to your doctor if you are having any side effects that are interfering with your quality of life. Do not stop taking metoprolol suddenly.
  • Do not substitute metoprolol succinate with metoprolol tartrate.
  • Always check that your prescription is correct. There have been several dosing errors involving metoprolol tablets.
  • Your doctor will need to regularly monitor your blood pressure and possibly other markers. Keep your appointments.
  • Metoprolol may impair your thinking or reaction time and affect your ability to drive. Drinking alcohol may enhance these effects. Do not drive if you think your driving ability is being compromised by metoprolol.
  • Talk to your doctor before taking metoprolol if you are pregnant, intending to become pregnant, or breastfeeding. Metoprolol may not be suitable for you.

6. Response and effectiveness

  • With oral metoprolol succinate extended-release (ER) tablets, peak concentrations are reached in about seven hours following a single dose. With regular dosing; however, concentrations of metoprolol remain steady and do not tend to fluctuate. Usually dosed once daily.
  • The blood pressure-lowering effects of metoprolol succinate ER tablets persist for about 24 hours following a single dose.

7. Interactions

Medicines that interact with metoprolol succinate may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with metoprolol succinate. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with metoprolol succinate include:

  • antidepressants, such as fluoxetine, paroxetine, St John’s Wort, and monoamine oxidase inhibitors
  • antifungals, such as terbinafine
  • antihistamines, such as diphenhydramine
  • bupropion, which may be used for the treatment of depression and as a stop-smoking aid
  • antimalaria agents, such as hydroxychloroquine
  • fingolimod, which may be used for the treatment of multiple sclerosis
  • HIV medications such as ritonavir
  • indigestion and heartburn medications, such as cimetidine and ranitidine
  • some medications used to treat mental illness, such as thioridazine
  • some heart medications, such as amiodarone, clonidine, digoxin, diltiazem, propafenone, quinidine, and verapamil
  • other medications including celecoxib, clonidine, hydralazine, and rifampicin
  • NSAIDs, such as diclofenac, ibuprofen, and indomethacin, may decrease the blood pressure-lowering capabilities of metoprolol.

People taking oral medications for diabetes may need to talk to their doctor about adjusting the dose of their medicine.

Note that this list is not all-inclusive and includes only common medications that may interact with metoprolol succinate. You should refer to the prescribing information for metoprolol succinate for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use metoprolol-succinate-ER only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: October 17, 2022.