Metoprolol

What is Metoprolol?

• Metoprolol (Lopressor; Toprol; Toprol XL) is a beta1-selective adrenoceptor blocking agent is widely used in the treatment of hypertension and angina pectoris.
• Metoprolol also is used in combination with other medications to treat heart failure.

Metoprolol Structure

Metoprolol ball-and-stick

What are the uses of this medicine?

Metoprolol (Lopressor;Toprol;Toprol XL) is used:

• for the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents
• in the long-term treatment of angina pectoris, to reduce angina attacks and to improve exercise tolerance.
• for the treatment of stable, symptomatic (NYHA Class II or III) heart failure of ischemic, hypertensive, or cardiomyopathic origin.

How does this medicine work?

• Metoprolol (met" oh proe' lol) is considered a “selective” beta-adrenergic receptor blocker in that it has potent activity against beta-1 adrenergic receptors which are found in cardiac muscle, but has little or no activity against beta-2 adrenergic receptors found on bronchial and vascular smooth muscle.
• The precise mechanism for the beneficial effects of beta-blockers in heart failure has not been elucidated.
• The mechanism of the antihypertensive effects of beta-blocking agents has not been elucidated.

However, several possible mechanisms have been proposed: (1) competitive antagonism of catecholamines at peripheral (especially cardiac) adrenergic neuron sites, leading to decreased cardiac output (2) a central effect leading to reduced sympathetic outflow to the periphery; and (3) suppression of renin activity.

Who Should Not Use this medicine ?

This medicine cannot be used in patients with:

• severe bradycardia
• second or third degree heart block
• cardiogenic shock
• decompensated cardiac failure
• sick sinus syndrome
• hypersensitive to any component of this product

What drug interactions can this medicine cause?

• Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Be sure to mention any of the following:

• bupropion (Aplenzin, Forfivo, Wellbutrin, Zyban)
• cimetidine
• clonidine (Catapres)
• diphenhydramine (Benadryl)
• fluoxetine (Prozac, Sarafem, Selfemra, in Symbyax)
• hydroxychloroquine
• paroxetine (Brisdelle, Paxil, Pexeva)
• propafenone (Rythmol)
• quinidine
• ranitidine (Zantac)
• reserpine
• ritonavir (Norvir, in Kaletra)
• terbinafine (Lamisil)
• thioridazine

Is this medicine FDA approved?

• Metoprolol was approved for use in the United States in 1978 and is still widely used in the therapy of hypertension and angina pectoris, with more than 27 million prescriptions filled yearly.
• Metoprolol is also used to reduce the risk of cardiovascular mortality after acute myocardial infarction.

How should this medicine be used?

Recommended dosage: Hypertension Adults:

• The usual initial dosage is 25 to 100 mg daily in a single dose.
• The dosage may be increased at weekly (or longer) intervals until optimum blood pressure reduction is achieved.
• In general, the maximum effect of any given dosage level will be apparent after 1 week of therapy.
• Dosages above 400 mg per day have not been studied.

• Metoprolol succinate extended-release is not recommended in pediatric patients < 6 years of age.

Angina Pectoris:

• The usual initial dosage is 100 mg daily, given in a single dose.
• Gradually increase the dosage at weekly intervals until optimum clinical response has been obtained or there is a pronounced slowing of the heart rate.
• Dosages above 400 mg per day have not been studied.

Heart Failure:

• The recommended starting dose of metoprolol succinate extended-release tablets is 25 mg once daily for two weeks in patients with NYHA Class II heart failure and 12.5 mg once daily in patients with more severe heart failure.
• Double the dose every two weeks to the highest dosage level tolerated by the patient or up to 200 mg of metoprolol succinate extended-release tablets.

Administration:

• Metoprolol comes as a tablet and an extended-release (long-acting) tablet to take by mouth.
• The regular tablet is usually taken once or twice a day with meals or immediately after meals.
• The extended-release tablet is usually taken once a day.
• To help you remember to take metoprolol, take it around the same time(s) every day.
• The extended-release tablet may be split.
• Swallow the whole or half tablets whole; do not chew or crush them.
• Your doctor may start you on a low dose of metoprolol and gradually increase your dose.
• Metoprolol controls high blood pressure and angina but does not cure them.
• Metoprolol extended-release tablets control heart failure but does not cure it.
• It may take a few weeks before you feel the full benefit of metoprolol.
• Continue to take metoprolol even if you feel well.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• Metoprolol is available in standard 50 and 100 mg tablets as well as 25, 50, 100 and 200 mg extended release tablets in generic forms as well as under the trade name of Lopressor and Toprol XL, and as a fixed combination with a hydrochlorothiazide as Lopressor HCT and Dutoprolol.
• Parenteral formulations for intravenous use are also available.

This medicine is available in fallowing brand namesː

• Lopressor;Toprol;Toprol XL

What side effects can this medication cause?

The most common side effects of this medicine include:

• tiredness, dizziness, depression, shortness of breath, bradycardia, hypotension, diarrhea, pruritus, rash

Metoprolol may cause serious side effects which may include:

• worsening of psoriasis, Peyronie’s disease, sweating, photosensitivity, taste disturbance
• hepatitis
• vomiting
• Confusion
• short-term memory loss
• headache
• somnolence
• nightmares
• insomnia
• anxiety/nervousness
• hallucinations
• paresthesia
• bronchospasm, dyspnea
• peripheral edema
• syncope
• chest pain
• hypotension

What special precautions should I follow?

• Worsening cardiac failure may occur. It may be necessary to lower the dose of metoprolol succinate extended-release or temporarily discontinue it. Heart failure patients should be advised to consult their physician if they experience signs or symptoms of worsening heart failure such as weight gain or increasing shortness of breath.
• Following abrupt cessation of therapy with certain beta-blocking agents, exacerbations of angina pectoris and, in some cases, myocardial infarction have occurred. Because coronary artery disease is common and may be unrecognized, avoid abruptly discontinuing metoprolol succinate extended-release in patients treated only for hypertension.
• Advise patients (1) to avoid operating automobiles and machinery or engaging in other tasks requiring alertness until the patient’s response to therapy with metoprolol succinate extended-release tablets has been determined; (2) to contact the physician if any difficulty in breathing occurs; (3) to inform the physician or dentist before any type of surgery that he or she is taking metoprolol succinate extended-release tablets.
• Advise patients to take metoprolol succinate extended-release tablets regularly and continuously, as directed, preferably with or immediately following meals. If a dose is missed, the patient should take only the next scheduled dose (without doubling it). Patients should not interrupt or discontinue metoprolol succinate extended-release tablets without consulting the physician.
• Avoid beta-blockers in patients with Bronchospastic Disease.
• If metoprolol succinate extended-release is used in the setting of pheochromocytoma, it should be given in combination with an alpha blocker, and only after the alpha blocker has been initiated. If required, first initiate therapy with an alpha blocker.
• Avoid initiation of high-dose extended release metoprolol in patients undergoing non-cardiac surgery because it has been associated with bradycardia, hypotension, stroke and death. Do not routinely withdraw chronic beta-blocker therapy prior to surgery.
• Beta-blockers may mask tachycardia occurring with hypoglycemia, but other manifestations such as dizziness and sweating may not be significantly affected.
• Consider initiating metoprolol succinate extended-release therapy at doses lower than those recommended for a given indication; gradually increase dosage to optimize therapy, while monitoring closely for adverse events.
• Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism, such as tachycardia. Abrupt withdrawal of beta-blockade may precipitate a thyroid storm.
• Patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction.
• Beta-blockers can precipitate or aggravate symptoms of arterial insufficiency in patients with peripheral vascular disease.
• Because of significant inotropic and chronotropic effects in patients treated with beta-blockers and calcium channel blockers of the verapamil and diltiazem type, caution should be exercised in patients treated with Calcium Channel Blockers concomitantly.
• Metoprolol has been linked to rare cases of drug induced liver injury.

What to do in case of emergency/overdose?

Symptoms of overdose may include:

• bradycardia
• hypotension
• cardiogenic shock
• atrioventricular block
• heart failure
• bronchospasm
• hypoxia
• impairment of consciousness/coma
• nausea and vomiting

Management of overdosage:

• Consider treating the patient with intensive care.
• Hemodialysis is unlikely to make a useful contribution to metoprolol elimination.
• Evaluate the need for atropine, adrenergic-stimulating drugs or pacemaker to treat bradycardia and conduction disorders.
• Treat underlying bradycardia. Consider intravenous vasopressor infusion, such as dopamine or norepinephrine.
• Heart failure and shock may be treated when appropriate with suitable volume expansion, injection of glucagon (if necessary, followed by an intravenous infusion of glucagon), intravenous administration of adrenergic drugs such as dobutamine, with α1 receptor agonistic drugs added in presence of vasodilation.
• Bronchospasm can usually be reversed by bronchodilators.

Can this medicine be used in pregnancy?

• Available data from published observational studies have not demonstrated a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes with metoprolol use during pregnancy.

Can this medicine be used in children?

• Safety and effectiveness of metoprolol succinate extended-release have not been established in patients <6 years of age.

What are the active and inactive ingredients in this medicine?

Active Ingredients:

• METOPROLOL SUCCINATE

Inactive Ingredients:

• ACETYLTRIBUTYL CITRATE
• Silicon Dioxide
• CELLULOSE, MICROCRYSTALLINE
• CROSCARMELLOSE SODIUM
• Hydroxypropyl Cellulose, Unspecified
• HYPROMELLOSES
• POLYETHYLENE GLYCOL 6000
• SODIUM STEARYL FUMARATE
• TALC
• TITANIUM DIOXIDE
• HYDROGENATED COTTONSEED OIL
• METHYLENE CHLORIDE
• ETHYLCELLULOSE

Who manufactures and distributes this medicine?

Manufactured by:

• Dr. Reddy’s Laboratories Limited
• Bachupally - INDIA

What should I know about storage and disposal of this medication?

• Store at 20°-25°C (68°-77°F).

Antihypertensive agents

• Dailymed label info on Metoprolol
• FDA Metoprolol

Metoprolol Resources
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