Metoprolol tartrate is a prescription heart medication used primarily to treat high blood pressure, chest pain from angina, and to reduce the risk of death after a heart attack. It belongs to a class of drugs called beta-blockers, and it works by slowing the heart rate and reducing the force of each heartbeat, which lowers the demand on your cardiovascular system.
How Metoprolol Tartrate Works
Metoprolol targets specific receptors on heart cells called beta-1 receptors. By blocking these receptors, it reduces heart rate and cardiac output both at rest and during physical activity. It also lowers systolic blood pressure during exercise. This selective targeting of the heart is what makes metoprolol “cardioselective,” meaning it mostly affects the heart rather than the lungs or blood vessels.
That selectivity isn’t absolute. At higher doses, metoprolol can also block receptors in the airways and blood vessels, which is why people with asthma or severe lung disease need to be cautious. However, compared to older, non-selective beta-blockers, metoprolol causes significantly less airway narrowing at equivalent doses.
After you take a tablet, you’ll typically feel its effects within one hour. How long those effects last depends on the dose: a 50 mg dose, for example, reaches half its peak effect at about 5 hours, while a 100 mg dose lasts closer to 6.4 hours. Because it wears off relatively quickly, metoprolol tartrate is usually taken two or three times per day.
Approved Uses
The FDA has approved metoprolol tartrate for three main conditions:
- High blood pressure (hypertension): It lowers blood pressure by reducing heart rate and the amount of blood the heart pumps with each beat. Treatment typically starts at 100 mg per day, taken as a single dose or split into two doses, and can be adjusted upward over several weeks.
- Chest pain from angina: By reducing how hard the heart works, metoprolol decreases the heart’s oxygen demand, which helps prevent the chest pain episodes that occur when the heart muscle doesn’t get enough blood flow. Starting doses are usually around 100 mg daily, split into two doses.
- After a heart attack (myocardial infarction): In patients who are medically stable after a heart attack, metoprolol tartrate reduces the risk of cardiovascular death. Treatment in this setting typically begins in the hospital, starting at 50 mg every 6 hours for two days before transitioning to 100 mg twice daily.
Off-Label Uses
Doctors sometimes prescribe metoprolol for conditions beyond its FDA-approved indications. Two of the more common off-label uses are migraine prevention and situational anxiety, sometimes called stage fright or performance anxiety. In both cases, the logic is similar: by calming the physical symptoms of a racing heart, trembling, and surging adrenaline, metoprolol can reduce the intensity of migraines triggered by vascular changes or quiet the pounding heart and shaky hands that come with public speaking.
The evidence for migraine prevention with metoprolol is less robust than for some other beta-blockers, but it remains a reasonable option, particularly for people who already take it for blood pressure or heart-related reasons.
Metoprolol Tartrate vs. Metoprolol Succinate
If you’ve seen both “metoprolol tartrate” and “metoprolol succinate” and wondered about the difference, it comes down to how the drug is released into your body. Metoprolol tartrate is an immediate-release tablet, so it enters your bloodstream quickly and needs to be taken two or three times a day to maintain steady levels. Metoprolol succinate is an extended-release formulation that releases the drug gradually, allowing once-daily dosing.
Both contain the same active ingredient, but the succinate form is also specifically approved for heart failure, while the tartrate form is not. Your prescriber will choose between them based on your specific condition and how many daily doses fit your routine.
Common Side Effects
Most side effects of metoprolol tartrate are mild and tend to improve as your body adjusts. In clinical trials for hypertension and angina, the most frequently reported problems were tiredness and dizziness, affecting about 10% of patients. Depression and diarrhea each occurred in roughly 5% of patients, as did skin itching or rash.
About 3% of patients experienced shortness of breath or a noticeably slow heart rate (bradycardia). Less common effects, each reported in about 1% of patients, included cold hands and feet, swelling in the legs, low blood pressure, wheezing, nausea, dry mouth, and stomach pain.
In the setting of a heart attack, side effects tend to be more pronounced because the heart is already under stress. Low blood pressure occurred in about 27% of patients, and a very slow heart rate (below 40 beats per minute) was seen in nearly 16%, compared to about 7% in those given a placebo.
Why You Should Never Stop Abruptly
One of the most important things to know about metoprolol tartrate is that you should not stop taking it suddenly. Abrupt withdrawal of beta-blockers can trigger a rebound effect where angina worsens significantly. In some cases, it has led to heart attacks. This risk exists even in people who were only taking metoprolol for high blood pressure, because undiagnosed coronary artery disease is common.
If you need to stop the medication, the standard approach is to gradually reduce the dose over one to two weeks. If chest pain worsens during this tapering period, the medication is typically restarted right away.
Who Should Avoid Metoprolol Tartrate
Metoprolol tartrate is not appropriate for everyone. People with a very slow resting heart rate, certain types of heart block (where electrical signals in the heart are significantly delayed), or severely low blood pressure generally cannot take this medication safely. It also requires caution in people with decompensated heart failure, where the heart is already struggling to pump enough blood to meet the body’s needs.
People with asthma or severe chronic obstructive pulmonary disease (COPD) should use metoprolol carefully, if at all. While its cardioselectivity means it affects the lungs less than non-selective beta-blockers, higher doses can still trigger airway tightening. Diabetes is another condition that warrants attention, because beta-blockers can mask the rapid heartbeat that normally alerts you to low blood sugar.