Metoprolol is available as immediate-release metoprolol tartrate (Lopressor) or extended release metoprolol succinate (Toprol-XL). It is also found combined with hydrochlorothiazide (as Dutoprol in the metoprolol succinate form and Lopressor HCT in the metoprolol tartrate form).
Overview
Metoprolol belongs to the group of heart/blood pressure drugs known as beta-blockers. That means they work partly by blunting the action of adrenaline, the body’s natural fight-or-flight chemical. People normally respond to stressful situations with a rapid pulse, a pounding heart and an increase in blood pressure. Metoprolol helps block such reactions by slowing the heart rate and relaxing the blood vessels so the heart does not have to pump as hard.
This medication is usually prescribed for high blood pressure, chest pain, heart attacks, and prevention of a second heart attack. The extended release metoprolol is also used in combination with other medications to treat heart failure. Although the FDA has not specifically approved its use for other purposes, doctors sometimes prescribe it to treat irregular heart rhythms or tremors and to prevent migraine headaches.
People’s Pharmacy Perspective
Beta blockers have been around a long time and generally have low cost generics available. One word of caution, however: We have heard from a significant number of people that not all generic Toprol XL (metoprolol succinate) is created equal. Some people have seen their blood pressure skyrocket while others have developed irregular heart rhythms. See their stories.
Beta blockers such as metoprolol should probably not be considered as first-line treatments for high blood pressure (1,2). British hypertension experts reserve beta blockers almost as a last resort, when other blood pressure medicines don’t work (3). Since beta blockers have the potential to cause numerous side effects (and negatively impact blood fats), we agree that they should be used cautiously.
Beta blockers are valuable for managing chest pain and preventing another heart attack after someone has already had one. They may also be valuable when adequate blood pressure control is not achieved with other classes of drugs. You and your physician will need to decide if the benefits outweigh the risks. The information provided here is not a substitute for the medical advice or care of a physician or other health care professional.
Special Precautions
DO NOT stop taking metoprolol (Lopressor, Toprol-XL) suddenly without first talking to your doctor. Stopping abruptly may trigger potentially fatal heart problems.
Pregnancy/Breastfeeding
Consult your doctor if you are pregnant or planning a pregnancy, or will be breastfeeding while taking this medication.
Who Should Avoid Metoprolol
Metoprolol is not recommended for some people: People who have had an allergic reaction to beta-blockers, metoprolol and people with certain serious heart problems, such as heart rates less than 45 beats per minute (for heart attack patients) or abnormal heart rhythms. The medication could occasionally lead to serious cardiac complications for these individuals. Note that only metoprolol succinate, the extended release tablet, is indicated for heart failure. Metoprolol tartrate is not recommended for people with heart failure.
Some people must be very carefully monitored if they take beta-blockers such as metoprolol. In general, people with heart failure must be extremely cautious if prescribed beta blockers because the medicine could lead to cardiac complications. Those prescribed metoprolol succinate are no exception; other medications they are on may need to be adjusted, and most importantly, they must be closely monitored for worsening of their heart condition.
Asthmatics and patients with other respiratory problems are especially vulnerable, as these drugs can make breathing worse. Metoprolol may be a little better than other beta-blockers in this regard, but monitor breathing carefully.
Diabetics should inform their physicians if they are taking metoprolol, since the medication may mask the signs of low blood sugar levels.
People with a history of depression should inform their doctors to ensure both their depression and beta-blocker therapy is well managed. Metoprolol is more likely to affect the nervous system than others in its class and may contribute to depression. People with a thyroid disorder should also be carefully monitored as metoprolol may mask signs of an overly active thyroid. Lastly, people with liver impairments may also need to be very carefully monitored.
Be certain to inform your doctor of any other conditions you may have. This information may affect your dose, whether you should even take this medication, or require you to take special tests during treatment.
Taking the Medicine
Metoprolol is best absorbed when taken with or right after meals. Food may reduce the risk of digestive tract upset and taking the drug at roughly the same time each day allows your body to maintain a constant level of the medication in your blood stream. This medication should be taken with a full glass of water. Avoid alcohol while on metoprolol because it could increase drowsiness or dizziness. Do not take calcium supplements or antacids within two hours of metoprolol because they may reduce absorption.
If surgery is scheduled, ask your surgeon and anesthesiologist to see if your beta blocker dose will need to be adjusted. Never stop taking metoprolol suddenly. Your doctor must reduce your dose gradually to prevent serious heart problems.
Adverse Effects and Interactions
Common Side Effects
- anxiety, nervousness
- dizziness or vertigo
- sleep problems (daytime drowsiness or insomnia)
- tired feeling
- abdominal pain or diarrhea
- decreased sex drive, impotence, or difficulty having an orgasm
- arthritis or gout pain
- elevated triglycerides and lower HDL cholesterol; a lipid test before treatment and periodically thereafter would be prudent.
Serious Side Effects
Obtain emergency medical care if you experience these signs of a potential allergic reaction:
- breathing difficulties
- swelling in your face, lips, tongue, or throat
Call your doctor promptly if you experience any of these serious side effects:
- feeling light-headed, fainting
- worsening depression, memory loss or mood swings
- wheezing, worsening asthma
- feeling short of breath, even with mild exertion
- extra-slow or uneven heartbeats
- stomach upset, low fever, lack of appetite, dark urine, pale-colored stools, jaundice (yellowing of the skin or eyes)
- swelling of your ankles or feet
- cold feeling in your hands and feet
- hives, itchiness, rash, increased susceptibility to sunburn
There may be other side effects not listed here. Talk to your doctor if your condition worsens and ask about any side effect that seems unusual or is especially bothersome. Never stop taking any beta blocker medication abruptly unless you are under very close medical supervision. Angina or a heart attack could occur.
Drug Interactions
- celecoxib (Celebrex): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- cimetidine (Tagamet): The combination could slow heart rate.
- clonidine (Catapres): If you are on both blood pressure medications, do not suddenly discontinue either medicine, as the increase in blood pressure could be life threatening.
- diclofenac (Cataflam, Voltaren): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- dolasetron (Anzemet): The combination increases the risk of heart rhythm disturbances.
- etodolac (Lodine): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- fenoprofen (Nalfon): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- flurbiprofen (Ansaid): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- hydralazine (Apresoline), propafenone (Rythmol), quinidine, and calcium channel blockers (verapamil (Calan), diltiazem (Cardizem CD)): These are also heart/blood pressure medications, which would have increased effects if given together with metoprolol. Taking beta-blockers with calcium channel blockers is generally not advised since the combined effects may lead to serious heart problems. If they must be taken together, the dose of one or both medications may need to be reduced and cardiac function should be carefully monitored.
- ibuprofen (Advil, Motrin): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- indomethacin (Indocin): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- insulin: Adding a beta-blocker such as metoprolol to the diabetes injection insulin can increase the risk of low blood sugar and make it harder to detect.
- ketorolac (Toradol): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- meloxicam (Mobic): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- naproxen (Aleve, Naprosyn): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
- propylthiouracil or methimazole (Tapazole): Beta-blockers may make treatment of thyroid disorders more complicated. Your physician will need to monitor such conditions closely.
- saquinavir (Invirase): The combination can increase the risk of irregular heart rhythms.
- sulindac (Clinoril): This NSAID could reduce the effectiveness of metoprolol and make you retain sodium and fluid.
Not every drug interaction could be listed here. Do not start any new medications or make changes to your treatment without first consulting your prescribing physician.
References
1. Lindholm, L. H., et al. “Should Beta-Blockers Remain First Choice in the Treatment of Primary Hypertension? A Meta-Analysis.” Lancet 2005; 366:1545-1553.
2. Kaplan, N.M., and Opie, L.H. “Controversies in Hypertension.” Lancet 2006; 367:168-176.
3. Beevers, D.G. “The End of Beta-Blockers for Uncomplicated Hypertension?” Lancet 2005; 366:1510-1512.
Be certain to consult a physician about your health, especially with regard to any signs or symptoms that may require diagnosis or medical attention. Information provided is not a substitute for the medical advice or care of a physician or other health care professional.
