Metoprolol succinate

Description

Metoprolol succinate is a beta 1-selective (cardioselective) adrenoceptor blocking agent intended for oral administration, available in the form of extended-release tablets. These tablets are specifically formulated to provide a controlled and predictable release of metoprolol, allowing for once-daily dosing. Each tablet contains a multiple unit system comprising metoprolol succinate in numerous controlled release pellets, with each pellet functioning as an independent drug delivery unit designed to release metoprolol continuously throughout the dosage interval.

The tablets are available in strengths of 23.75 mg, 47.5 mg, 95 mg, and 190 mg of metoprolol succinate, which are equivalent to 25 mg, 50 mg, 100 mg, and 200 mg of metoprolol tartrate, USP, respectively. The chemical name of metoprolol succinate is (±)1-(isopropyl amino)-3-p-(2-methoxyethyl) phenoxy-2-propanol succinate (2:1) (salt), and its structural formula is represented accordingly. Metoprolol succinate, USP appears as a white to off-white powder with a molecular weight of 652.8. It is freely soluble in water, soluble in methanol, sparingly soluble in alcohol, and slightly soluble in isopropyl alcohol.

Inactive ingredients in the formulation include acetyl tributyl citrate, carnauba wax, colloidal silicon dioxide, ethylcellulose, glyceryl dibehenate, hydroxypropyl cellulose, hypromellose, microcrystalline cellulose, polyethylene glycol, sodium stearyl fumarate, and titanium dioxide.

Uses and Indications

Metoprolol succinate is indicated for the treatment of hypertension, angina pectoris, and heart failure. In patients with hypertension, this medication is utilized to lower blood pressure, thereby reducing the risk of both fatal and non-fatal cardiovascular events, including strokes and myocardial infarctions.

In the context of angina pectoris, metoprolol succinate serves to alleviate symptoms associated with this condition. Additionally, it is indicated for the management of heart failure, where it has been shown to reduce the risk of cardiovascular mortality and hospitalizations due to heart failure.

There are no teratogenic or nonteratogenic effects associated with metoprolol succinate.

Dosage and Administration

The medication is to be administered once daily. Dosing should be titrated at weekly or longer intervals as needed and tolerated.

For the management of hypertension, the starting dose is between 25 mg and 100 mg. In cases of angina pectoris, the recommended starting dose is 100 mg. For heart failure, the initial dose may be either 12.5 mg or 25 mg, depending on the patient's condition and response.

When transitioning from immediate-release metoprolol to metoprolol succinate extended-release tablets, it is essential to maintain the same total daily dose of metoprolol succinate extended-release tablets as the patient was receiving with the immediate-release formulation.

Contraindications

Use of this product is contraindicated in patients with known hypersensitivity to any of its components. Additionally, it should not be administered to individuals with severe bradycardia, including those with greater than first-degree heart block or sick sinus syndrome who do not have a pacemaker. The product is also contraindicated in cases of cardiogenic shock or decompensated heart failure, due to the potential for exacerbating these conditions.

Warnings and Precautions

Abrupt cessation of therapy may lead to exacerbation of myocardial ischemia, necessitating careful consideration of discontinuation protocols. In patients with heart failure, there is a risk of worsening cardiac failure, which should be monitored closely.

Beta-blockers are contraindicated in individuals with bronchospastic disease due to the potential for adverse respiratory effects. Additionally, the concomitant use of beta-blockers with glycosides, clonidine, diltiazem, or verapamil may significantly increase the risk of bradycardia, warranting vigilant monitoring of heart rate and rhythm.

For patients diagnosed with pheochromocytoma, it is imperative to initiate therapy with an alpha blocker to mitigate the risk of hypertensive crises. In the context of non-cardiac surgery, high-dose extended-release metoprolol should not be initiated, and chronic beta-blocker therapy should not be routinely withdrawn prior to surgical procedures to avoid complications.

Healthcare professionals should be aware that beta-blockers may increase the risk of hypoglycemia and can mask the early warning signs of this condition, necessitating careful blood glucose monitoring in at-risk patients. In cases of thyrotoxicosis, abrupt withdrawal of beta-blockers may precipitate a thyroid storm, which requires immediate medical attention.

Patients with peripheral vascular disease may experience aggravated symptoms of arterial insufficiency, and caution should be exercised in this population. Furthermore, it is important to note that patients may exhibit unresponsiveness to standard doses of epinephrine used for the treatment of allergic reactions, which could complicate emergency management.

Ongoing assessment and monitoring of these factors are essential to ensure patient safety and effective management during treatment.

Side Effects

Patients receiving treatment may experience a range of adverse reactions. The most common adverse reactions reported include tiredness, dizziness, depression, shortness of breath, bradycardia, hypotension, diarrhea, pruritus, and rash.

Serious adverse reactions may occur, including worsening cardiac failure and exacerbation of myocardial ischemia following abrupt cessation of therapy. Patients with bronchospastic disease should avoid beta-blockers due to the potential for adverse effects. The concomitant use of glycosides, clonidine, diltiazem, and verapamil with beta-blockers can increase the risk of bradycardia. In patients with pheochromocytoma, therapy should be initiated with an alpha blocker.

It is important to note that high-dose extended-release metoprolol should not be initiated in patients undergoing non-cardiac surgery, and chronic beta-blocker therapy should not routinely be withdrawn prior to surgery. Additionally, patients may experience an increased risk of hypoglycemia, with the potential to mask early warning signs. Abrupt withdrawal in patients with thyrotoxicosis may precipitate a thyroid storm, and symptoms of arterial insufficiency may be aggravated in those with peripheral vascular disease. Furthermore, patients may be unresponsive to the usual doses of epinephrine used to treat allergic reactions.

In cases of overdosage, patients may present with severe bradycardia, hypotension, and cardiogenic shock. Other clinical manifestations can include atrioventricular block, heart failure, bronchospasm, hypoxia, impairment of consciousness or coma, nausea, and vomiting.

Contraindications for this treatment include known hypersensitivity to the product components, severe bradycardia (greater than first-degree heart block or sick sinus syndrome without a pacemaker), and cardiogenic shock or decompensated heart failure.

Drug Interactions

Catecholamine-depleting drugs may exhibit an additive effect when administered concurrently with beta-blocking agents, potentially leading to enhanced pharmacological effects. Clinicians should monitor patients closely for signs of increased hypotension or bradycardia and consider dosage adjustments as necessary.

CYP2D6 inhibitors are known to increase the concentration of metoprolol. It is advisable to monitor patients for increased effects of metoprolol, and dosage adjustments may be warranted based on clinical response and tolerability.

Beta-blockers, including metoprolol, have the potential to exacerbate rebound hypertension following the withdrawal of clonidine. It is recommended that clinicians exercise caution when discontinuing clonidine in patients receiving beta-blockers and consider gradual tapering of clonidine to mitigate this risk. Monitoring blood pressure during this transition is essential to ensure patient safety.

Packaging & NDC

The table below lists all NDC Code configurations of Metoprolol Succinate, the U.S. brand-name prescription product. Columns show Packaging, Formulation Type, and Active Ingredient Strength.

Pediatric Use

One hundred forty-four hypertensive pediatric patients aged 6 to 16 years were randomized to receive either placebo or one of three dose levels of metoprolol succinate extended-release tablets (0.2, 1, or 2 mg/kg once daily) over a 4-week period. The study did not achieve its primary endpoint of demonstrating a dose response for reduction in systolic blood pressure (SBP). However, some pre-specified secondary endpoints indicated effectiveness, including a dose-response for reduction in diastolic blood pressure (DBP) and significant changes in SBP when comparing 1 mg/kg and 2 mg/kg doses to placebo.

The mean placebo-corrected reductions in SBP ranged from 3 to 6 mmHg, while reductions in DBP ranged from 1 to 5 mmHg. Additionally, the mean reduction in heart rate was between 5 to 7 bpm, with some individuals experiencing considerably greater reductions.

No clinically relevant differences in the adverse event profile were noted between pediatric patients aged 6 to 16 years and adult patients. It is important to note that the safety and effectiveness of metoprolol succinate extended-release tablets have not been established in patients younger than 6 years of age.

Geriatric Use

Clinical studies of metoprolol succinate extended-release tablets in the treatment of hypertension did not include a sufficient number of subjects aged 65 and older to determine whether these elderly patients respond differently compared to younger individuals. However, other clinical experiences in hypertensive patients have not identified significant differences in responses between elderly and younger patients.

In the MERIT-HF trial, which involved 1,990 patients with heart failure randomized to metoprolol succinate extended-release tablets, 50% of the participants were aged 65 years and older, and 12% were aged 75 years and older. The findings from this trial indicated no notable differences in efficacy or the rate of adverse reactions between older and younger patients.

Given the greater frequency of decreased hepatic, renal, or cardiac function, as well as the presence of concomitant diseases or other drug therapies in elderly patients, it is generally recommended to initiate treatment with a low starting dose in this population. Careful monitoring is advised to ensure safety and efficacy in geriatric patients.

Pregnancy

Untreated hypertension and heart failure during pregnancy can lead to adverse outcomes for both the mother and the fetus. 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. However, there are inconsistent reports regarding intrauterine growth restriction, preterm birth, and perinatal mortality associated with maternal use of beta-blockers, including metoprolol.

In animal reproduction studies, metoprolol has been shown to increase post-implantation loss and decrease neonatal survival in rats at oral dosages of 500 mg/kg/day, which is approximately 24 times the daily dose of 200 mg in a 60-kg patient on a mg/m² basis. Conversely, no fetal abnormalities were observed when pregnant rats received metoprolol orally at doses up to 200 mg/kg/day, equivalent to 10 times the daily dose of 200 mg in a 60-kg patient.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown; however, all pregnancies carry a background risk of birth defects, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications, such as the need for cesarean section and post-partum hemorrhage. Additionally, hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death, necessitating careful monitoring and management of pregnant women with hypertension.

Metoprolol crosses the placenta, and neonates born to mothers receiving metoprolol during pregnancy may be at risk for hypotension, hypoglycemia, bradycardia, and respiratory depression. Therefore, it is recommended that neonates be observed and managed accordingly. While the published literature has reported inconsistent findings regarding intrauterine growth retardation, preterm birth, and perinatal mortality with maternal use of metoprolol, methodological limitations in these studies, such as retrospective design and concomitant use of other medications, hinder definitive conclusions about any drug-associated risk during pregnancy.

Lactation

Limited available data from published literature report that metoprolol is present in human milk. The estimated daily infant dose of metoprolol received from breast milk ranges from 0.05 mg to less than 1 mg, with an estimated relative infant dosage of 0.5% to 2% of the mother's weight-adjusted dosage.

No adverse reactions of metoprolol on the breastfed infant have been identified. However, it is recommended that healthcare professionals monitor the breastfed infant for bradycardia and other symptoms of beta blockade, such as listlessness or hypoglycemia.

There is no information regarding the effects of metoprolol on milk production. In a small study involving three mothers (at least 3 months postpartum) who took metoprolol of unspecified amounts, breast milk was collected every 2 to 3 hours over one dosage interval. The average amount of metoprolol present in breast milk was 71.5 mcg/day (range 17 to 158.7), with an average relative infant dosage of 0.5% of the mother's weight-adjusted dosage. In two women taking unspecified amounts of metoprolol, milk samples taken after one dose indicated that the estimated amount of metoprolol and alpha-hydroxy metoprolol in breast milk was less than 2% of the mother's weight-adjusted dosage.

Renal Impairment

There is no information available regarding dosage adjustments, special monitoring, or safety considerations for patients with renal impairment. Healthcare professionals should exercise caution and consider the lack of specific guidance when prescribing to patients with reduced kidney function.

Hepatic Impairment

There is no information available regarding the use of this medication in patients with hepatic impairment. Consequently, there are no dosage adjustments, special monitoring requirements, or precautions specified for individuals with compromised liver function. Healthcare professionals should exercise caution and consider the overall clinical context when prescribing this medication to patients with liver problems, as the absence of specific guidance necessitates careful evaluation of potential risks and benefits.

Overdosage

Overdosage of metoprolol succinate can result in a range of severe clinical manifestations. The most notable signs and symptoms include severe bradycardia, hypotension, and cardiogenic shock. Additionally, patients may present with atrioventricular block, heart failure, bronchospasm, hypoxia, and varying levels of consciousness, including coma. Gastrointestinal symptoms such as nausea and vomiting may also occur.

In the event of an overdose, it is crucial to consider intensive care management, particularly for patients with underlying conditions such as myocardial infarction or heart failure, as they may experience significant hemodynamic instability. It is important to note that beta-blocker overdose can lead to considerable resistance to resuscitation efforts with adrenergic agents, including beta-agonists.

Management strategies should be tailored based on the pharmacologic actions of metoprolol:

Bradycardia

For bradycardia and associated conduction disorders, the need for atropine should be evaluated. In cases where bradycardia persists, adrenergic-stimulating drugs or the use of a pacemaker may be necessary.

Hypotension

Management of hypotension should focus on addressing the underlying bradycardia. Intravenous vasopressor infusion, such as dopamine or norepinephrine, may be warranted to stabilize blood pressure.

Heart Failure and Shock

In instances of heart failure and shock, appropriate treatment may include volume expansion and the administration of glucagon. If glucagon is utilized, an intravenous infusion may be required following the initial injection. Additionally, intravenous administration of adrenergic drugs such as dobutamine may be beneficial, with α1 receptor agonists considered in the presence of vasodilation.

Bronchospasm

Bronchospasm associated with metoprolol overdose can typically be reversed with bronchodilators.

It is important to note that hemodialysis is unlikely to significantly enhance the elimination of metoprolol from the body. Therefore, supportive care and the aforementioned interventions are critical in managing an overdose effectively.

Nonclinical Toxicology

Long-term studies in animals have been conducted to evaluate the carcinogenic potential of metoprolol tartrate. In two-year studies in rats at three oral dosage levels of up to 800 mg/kg/day (41 times, on a mg/m² basis, the daily dose of 200 mg for a 60-kg patient), there was no increase in the development of spontaneously occurring benign or malignant neoplasms of any type. The only histologic changes that appeared to be drug-related were an increased incidence of generally mild focal accumulation of foamy macrophages in pulmonary alveoli and a slight increase in biliary hyperplasia. In a 21-month study in Swiss albino mice at three oral dosage levels of up to 750 mg/kg/day (18 times, on a mg/m² basis, the daily dose of 200 mg for a 60-kg patient), benign lung tumors (small adenomas) occurred more frequently in female mice receiving the highest dose than in untreated control animals. There was no increase in malignant or total (benign plus malignant) lung tumors, nor in the overall incidence of tumors or malignant tumors. This 21-month study was repeated in CD-1 mice, and no statistically or biologically significant differences were observed between treated and control mice of either sex for any type of tumor.

All genotoxicity tests performed on metoprolol tartrate, including a dominant lethal study in mice, chromosome studies in somatic cells, a Salmonella/mammalian-microsome mutagenicity test, and a nucleus anomaly test in somatic interphase nuclei, were negative. Additionally, metoprolol succinate was also evaluated in a Salmonella/mammalian-microsome mutagenicity test, which yielded negative results.

No evidence of impaired fertility due to metoprolol tartrate was observed in a study performed in rats at doses up to 22 times, on a mg/m² basis, the daily dose of 200 mg in a 60-kg patient.

Postmarketing Experience

No specific postmarketing experience details have been reported. As such, there are currently no additional adverse events or rare case reports to summarize.

Patient Counseling

Patients should be advised to take metoprolol succinate extended-release tablets regularly and continuously, as directed, preferably with or immediately following meals. In the event that a dose is missed, patients should take only the next scheduled dose and should not double the dose. It is important for patients to understand that they should not interrupt or discontinue the use of metoprolol succinate extended-release tablets without first consulting their physician.

Healthcare providers should inform patients to avoid operating automobiles and machinery or engaging in other tasks that require alertness until their response to therapy with metoprolol succinate extended-release tablets has been determined. Patients should be instructed to contact their physician if they experience any difficulty in breathing. Additionally, patients should inform their physician or dentist prior to any type of surgery that they are taking metoprolol succinate extended-release tablets.

For patients with heart failure, it is crucial to advise them to consult their physician if they notice any signs or symptoms of worsening heart failure, such as weight gain or increasing shortness of breath. Patients or caregivers should also be informed about the risk of hypoglycemia when metoprolol succinate extended-release tablets are administered to patients who are fasting or experiencing vomiting. It is essential to instruct patients or caregivers on how to monitor for signs of hypoglycemia effectively.

Storage and Handling

The product is supplied in various package configurations, with specific NDC numbers available upon request. It should be stored at a controlled room temperature of 25°C (77°F). Temporary excursions are permissible within the range of 15 to 30°C (59 to 86°F), in accordance with USP guidelines for controlled room temperature. Proper storage conditions are essential to maintain the integrity and efficacy of the product.

Additional Clinical Information

No further data are available.

FDA Insert (PDF)

This document is the official FDA-approved prescribing information for Metoprolol Succinate as submitted by Granules India Limited. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)