Metoprolol Tartrate side effects and drug information

Metoprolol is a prescription medicine that comes in a variety of forms. It is available in two types of tablets, which are immediate-release and extended-release, and is also available as an extended-release oral capsule. Metoprolol comes in an injectable version as well, but a health care practitioner only administers this form.  

Trade Names Lopressor, Metolar XR, others, Lopressor, Metolar XR, Toprol XL
PubChem CID 4171
ChemSpider ID 4027
Protein binding 12%
CAS ID 37350-58-6
Molar mass 267.364 g/mol
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For the oral tablet, it comes as a brand name Lopressor and Toprol XL. These two brand names are both metoprolol, but they each have different salt forms. Lopressor is a metoprolol tartrate, which is an immediate- release form, while Toprol XL is metoprolol succinate and is an extended-release form. The latter stays longer in the bloodstream.

The difference in their salt forms allows each medicine to treat different conditions. This medication is available in a generic version as well.

Side Effects

Metoprolol may potentially cause some side effects, which may be mild or severe. That is why it is essential to always follow your doctor’s instructions on the usage of the drug to prevent or avoid the experience of side effects.

Some of its common side effects include:

  • Diarrhea
  • Drowsiness
  • Tiredness
  • Dizziness
  • Slow heartbeat
  • Decreased libido (though this one is rare)

To lessen lightheadedness and dizziness reaction, slowly get up when rising from a lying or sitting position.  

The patient may also experience their hands and feet to be cold. This is due to the reduction of blood flow that is going through the hands and feet, to not make this effect worse, avoid smoking or the use of tobacco. When feeling cold, and burning, dress warmly to keep yourself warm.

For the serious side effects, some of these are:

  • Very slow heartbeat
  • Severe dizziness
  • Fainting
  • Mood changes that may include depression, mood swings and confusion
  • Fingers or toes turning blue
  • Difficulty in breathing
  • Newly developed or worsening heart failure symptoms such as shortness of breath, sudden weight gain, unusual fatigue, and swelling of the ankles and feet.

Indication and Dosage

The appropriate dosage for this medicine will depend on the medical condition that is being treated as well as the patient’s response to the drug after the initial treatment.

Metoprolol is taken by mouth and should be consumed along with a meal either during or right after. This can be taken 1 to 3 times a day, and it is important always to follow the doctor’s instructions.

To decrease the occurrence of side effects, it is recommended to begin the treatment with a low dosage, then gradually increase according to the doctor’s advice. In order to experience the efficacy of this drug, and improve your condition, take the medicine consistently. Also, do not abruptly stop the treatment as it may cause other side effects. See your health care provider before stopping or changing your dosage.

For the treatment of high blood pressure, it may take longer before feeling the improvement in your condition. Continue with the drug even if you are starting to feel better and finish your recommended treatment.

Taking this medicine constantly as ordered by the doctor will help avoid the experience of chest pain, 2nd heart attack, or migraine. If you are already experiencing chest pain or migraine, do not use this drug to treat these conditions, ask your doctor what to take instead.

If your condition does not improve or gets worse with this treatment, inform your health care provider.

Drug Interaction

Interactions of drugs may alter how each function and may potentially cause severe side effects. Inform your doctor about all your other medications prior to the treatment with this drug to reduce the risk of adverse reactions. Some medicines may contain ingredients that could increase blood pressure, heart rate, or make heart failure worse.

Consult with your doctor before changing your dosage, stopping, or starting the medicine. Also, be aware of safely using other drugs such as the most commonly used ones like cough and cold products, NSAIDs like naproxen and ibuprofen, or diet aids.

Metoprolol may cause interactions with other drugs such as fingolimod, lumefantrine, propafenone, quinidine, SSRI, St. John’s Wort, and antidepressants like fluoxetine and paroxetine.

Warnings and Precautions

Prior to using this product, inform your health care provider if you are allergic to metoprolol or other beta-blockers such as atenolol or propranolol. Also mention if you have other allergies as this drug may have some other inactive components that may lead to an allergic reaction.

It is also necessary that you inform your doctor about any medical conditions or history that you may have especially certain forms of heart rhythm problems. Like sick sinus syndrome, slow heartbeat, 2nd or 3rd-degree atrioventricular block; breathing issues such as emphysema, chronic bronchitis, or asthma; liver disease, heart failure, severe allergic reactions including treatment with epinephrine; blood circulation issues like Raynaud’s disease and peripheral vascular disease; mood disorder like depression, muscle disorder like myasthenia gravis.

For those who have diabetes, be aware that this drug may hide the fast heartbeat that you experience with hypoglycemia. Some other symptoms of hypoglycemia are sweating and dizziness. This medication may cause you difficulty in controlling your blood sugar.  

If you have diabetes and are using this product, check your blood sugar constantly. And if you start having symptoms of high blood sugar such as an increase in urination or thirst, consult your doctor as your dosage may need to be adjusted, or you may be required to have an exercise program or change in diet.

Metoprolol may cause dizziness or drowsiness. Avoid driving or using machinery and limit alcohol use. Inform your doctor as well if you are using cannabis, and if you are pregnant or breastfeeding.

Overdose and Contraindications

Discuss with your doctor about changes in lifestyle that may accompany this treatment to improve your condition better. Some of these are changing in diet, exercise, and stress reduction programs.

If you are taking metoprolol, constantly check your blood pressure and heart rate, as well as do lab tests periodically like liver function test to assess your progress or check if there are side effects.

Clinical Pharmacology

This drug is used to treat hypertension, lower the blood pressure to prevent stroke, heart attack, and other kidney problems, and may also be used as a treatment for chest pain. Metoprolol may also help in improving survival after a heart attack.

This product may also be used along with other medicines.

Medication Guide

If you miss a dosage, never double the dose to catch up. Just take the next one as soon as possible, but if close to the next dosage, take the next dose at the regular time.

Store metoprolol at room temperature and away from light and moisture.