Metoprolol succinate belongs to the class of drugs known as beta-blockers. These drugs are primarily used for treating hypertension (high blood pressure) and angina (chest pain).

This is a prescription drug, meaning you are going to need a doctor's prescription to acquire this drug.

This drug mainly works by blocking beta-1 selective adrenergic receptors. The result of this is a slowing down of the heart rate and the force of contraction, thereby reducing the workload on the heart muscles.

This drug can be used to treat a variety of conditions, including high blood pressure, acute myocardial infarction (heart attack), and congestive heart failure.

Despite all the advantages, this drug also has an extensive side effect profile as well including diarrhoea, nausea and lightheadedness.

In this article, we will discuss what Metoprolol succinate is? What are the clinical indications? What is the mechanism of action? And also, what are the common side effects of this drug.

Generic name:

• Metoprolol succinate

Common brand names:

Some of the common brand names of metoprolol succinate include:

• Dutoprol
• Kapspargo
• Lopresor
• Lopressor
• Lopressor Hct
• Toprol

Drug class:

This belongs to the drug class known as beta-blockers.

Mechanism of action:

This drug is the selective beta-1 receptor antagonist with little to no effect on beta-2 receptors at oral doses of less than 100mg in adults. It decreases cardiac output by negative inotropic and chronotropic effects. There is no intrinsic sympathomimetic or membrane-stabilizing activity with this drug. It has been demonstrated that metoprolol reduces cardiac output and heart rate in normal subjects, the reduction possibly being related to the dose and concentration of the drug.

Clinical indications of Metoprolol Succinate

The following conditions can be treated with metoprolol succinate:

• Hypertension (increased blood pressure)
• Angina pectoris (Chest pain)
• Prophylactic treatment of stable heart failure
• Migraine (off-label)
• Atrial fibrillation (off-label)

Dosage of Metoprolol Succinate

Dosage of Metoprolol Succinate is different for different conditions:

• Hypertension

Initial dose (loading dose):

-Start with 100mg orally once daily

-The dose can be increased after 1 week or as per your doctor's instructions

Maximum dose:

-450 mg/day orally

• Angina

Initial dose (loading dose):

-Start with 100mg orally once daily

-The dose can be increased after 1 week or as per your doctor's instructions

Maximum dose:

-400 mg/day orally

• Heart failure (prophylaxis)

Initial dose (loading dose):

-Start with 25 mg/day orally once daily  in patients with NYHA Class II heart failure

-Start  in patients with more severe heart failure

-Increase the dose after every two weeks or as per your physician's instructions

Maximum dose:

-200 mg/day orally

• Migraine (off-label):

Initial dose (loading dose):

-50 mg orally twice daily

• Arterial fibrillation (off-label):

Initial dose (loading dose):

-Initially, start with 2-5 mg intravenously every 5 minutes

-Do not exceed the dose over 15 mg over 10- 15 minutes

Maintenance dose:

-25-100 mg orally twice daily

Formulations:

Metoprolol succinate is available in the following formulations:

• Oral tablet
• IV injections

Side effects of Metoprolol Succinate

The side effect profile of each drug varies from person to person. You may not get any of the side effects given below or may get only a few. This article only covers the side effects that are common among the general population. Exceptions are always there. Some of the common side effects of this drug include:

• Dizziness
• Tiredness
• Breathing difficulties such as wheezing, coughing, and shortness of breath
• Headache
• Diarrhoea
• Bradycardia (slow heart rate)
• Reduced libido (reduced interest in sex)
• Rash
• Decreased exercise tolerance
• Confusion 
• Memory problems
• Nightmares
• Trouble sleeping

Contraindications of Metoprolol Succinate

Metoprolol is contraindicated in the following conditions:

• Patients having sick sinus syndrome ( a condition in which normal pacemakers of the heart does not function normally)
• Second or third-degree heart block ( abnormal heart rhythm results due to blockage in the conduction pathway of the heart)
• Hypotension (decreased blood pressure)
• Having hypersensitivity (allergic reaction) to the metoprolol itself or any of the other inactive ingredients of the drug.

Precautions of Metoprolol Succinate

The medicine can be taken with or without food, as per the direction of your doctor. If you are self-medicating yourself with this drug, make sure you thoroughly read all the instructions given on the product leaflet.

If you're taking this medicine in liquid form, measure the dose carefully with a special measuring spoon usually provided with the medicine. Do not measure your dose with household items such as spoons etc., because you might not get the correct dosage.

You have to remember that the dosage of any drug may differ based on age, condition, and a patient's response to therapy. Make sure you do not take this medicine above the recommended dose. In case your doctor prescribed this drug to you, follow his directions.

Before starting any medication, keep the following points in mind:

• Before starting any medication, tell your pharmacist about your drug allergies (if any) because sometimes a drug contains inactive ingredients along with the salts that may flare up your allergies.
• You should let your physician know about any of your other medical conditions such as liver disease, renal disease, etc.
• Always make sure that you read the medication guide carefully. When in doubt about any medication, it is best to consult your pharmacist or your physician.
• You should let your doctor know if you are pregnant or planning on becoming pregnant during the course of therapy.
• You should take your medications at the proper time and not try to alter the dosage yourself.
• To get the most benefit from your medications, you must take them on time.
• If you are taking any other medications, vitamins or herbal products along with. In that case, it is best to let your pharmacist or your doctor know about that medication so that any adverse effects due to drug interaction can be avoided.
• Tell your doctor if your condition persists or worsens over time.

Special instructions of Metoprolol Succinate

• Pregnancy: Though not enough studies are available to know for certain about the safety of this drug during pregnancy. Do not stop using this drug without consulting your physician first, as sudden discontinuation may result in withdrawal syndrome.
• Nursing mothers: Metoprolol dose gets excreted in the breast milk, but the quantity is so low that it does not result in any potential side effects. If you are uncertain about the use of this drug while nursing, consult your physician.
• In the event of abrupt discontinuation, a withdrawal syndrome could result, potentially resulting in myocardial infarction and or angina. Both hypertension and tachycardia are common in withdrawal syndrome.

Drug interactions of Metoprolol Succinate

When your physician or pharmacist prescribes you a medication, they are already aware of any possible interactions. You mustn't make any change in the medication prescribed to you by your physician.

If you are unsure about the drug interactions or have any queries about your prescription, you can talk to your doctor or pharmacist. You can also keep a list of your medication and show that to your pharmacist or your physician so they may know all the drugs you are using and make their decision accordingly.

This article does not contain all the possible drug interactions, but it will cover some of the more basic interactions:

• Monoamine oxidase inhibitors (MAOIs): co-administration of MAOIs and metoprolol results in increased plasma concentrations of metoprolol. As a result, a patient may feel lightheaded. Some of the common MAOIs include isocarboxazid, selegiline and phenelzine etc.
• Calcium channel blockers: Calcium channel blockers are also used to treat several heart conditions. When these drugs are co-administered with metoprolol, the result may be severely decreased heart rate. Some examples of Ca+ channel blockers include amlodipine and diltiazem.
• Alpha-blockers: Alpha-blocker drugs are also used to lower blood pressure, and when used simultaneously with metoprolol, the result can be an abnormal lowering of blood pressure. Some of the examples of alpha-blockers are prazosin and clonidine.

Overdose of Metoprolol Succinate

Overdose may be accidental or purposeful. You should keep in mind that if you miss a dose, do not try to compensate by taking the extra dose when the next dose is due. You can consult your physician or your pharmacist about the doses you missed.

If the patient has collapsed, has trouble breathing, or can't be awakened, you should immediately call your physician.

Treatment will vary according to the amount of drug consumed, age of,.the patient other comorbidities.

Some of the common symptoms of poisoning include:

• Irregular heartbeat
• Decreased blood pressure
• Lightheadedness
• Heart failure

Storage of Metoprolol Succinate

Following steps must be taken to store medicine properly:

• Keep your medications in the same container they came in.
• Store your medicine at room temperature. Keep your medication away from direct sunlight and excessive moisture.