Dosage Form
Tablet
Route
ORAL
About This Medication
11 DESCRIPTION Metoprolol tartrate tablets, USP contain metoprolol tartrate, USP a selective beta 1 -adrenoreceptor blocking agent. Metoprolol tartrate, USP is (±)-1-(Isopropylamino)-3-[p-(2-methoxyethyl) phenoxy]-2-propanol L-(+)tartrate (2:1) salt, and its structural formula is Metoprolol tartrate, USP is a white, practically odorless, crystalline powder with a molecular weight of 684.82. It is very soluble in water; freely soluble in methylene chloride, in chloroform, and in alcohol; slightly soluble in acetone; and insoluble in ether. Metoprolol tartrate tablets, USP are available as 25 mg, 50 mg and 100 mg tablets for oral administration containing 25 mg, 50 mg and 100 mg metoprolol tartrate, respectively. Inactive Ingredients: microcrystalline cellulose, lactose monohydrate, povidone, croscarmellose sodium, colloidal silicon dioxide, magnesium stearate hypromellose, titanium dioxide and polyethylene glycol. In addition, the 50 mg product contains D&C Red No. 30 Aluminum Lake and the 100 mg product contains FD&C Blue No. 2 Aluminum Lake and FD&C Blue No. 1 Aluminum Lake as coloring agents. metoprolol-tartrate-structure
Active Ingredients
| Ingredient |
Strength |
| Metoprolol Tartrate |
- |
Indications & Usage
1 INDICATIONS AND USAGE Metoprolol tartrate tablet is a beta-adrenergic blocker indicated for the treatment of: • Hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions. ( 1.1 ) • Angina Pectoris. ( 1.2 ) • Myocardial Infarction, to reduce the risk of cardiovascular mortality when used in conjunction with intravenous metoprolol therapy in patients with definite or suspected acute myocardial infarction in hemodynamically stable patients. ( 1.3 ) 1.1 Hypertension Metoprolol tartrate tablets are indicated for the treatment of hypertension in adult patients, to lower blood pressure. Lowering blood pressure lowers the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including metoprolol. Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than 1 drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal. Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of therapy. Metoprolol tartrate tablets may be administered with other antihypertensive agents. 1.2 Angina Pectoris Metoprolol tartrate tablets are indicated in the long-term treatment of angina pectoris, to reduce angina attacks and to improve exercise tolerance. 1.3 Myocardial Infarction Metoprolol tartrate tablets are indicated in the treatment of hemodynamically stable patients with definite or suspected acute myocardial infarction to reduce cardiovascular mortality when used alone or in conjunction with intravenous metoprolol.
How It Works
12.1 Mechanism of Action Metoprolol is a beta 1 -selective (cardioselective) adrenergic receptor blocking agent. This preferential effect is not absolute, however, and at higher plasma concentrations, metoprolol also inhibits beta 2 -adrenoreceptors, chiefly located in the bronchial and vascular musculature. Metoprolol has no intrinsic sympathomimetic activity, and membrane-stabilizing activity is detectable only at plasma concentrations much greater than required for beta-blockade. Animal and human experiments indicate that metoprolol slows the sinus rate and decreases AV nodal conduction. The relative beta 1 -selectivity of metoprolol has been confirmed by the following: (1) In normal subjects, metoprolol is unable to reverse the beta 2 -mediated vasodilating effects of epinephrine. This contrasts with the effect of nonselective beta-blockers, which completely reverse the vasodilating effects of epinephrine. (2) In asthmatic patients, metoprolol reduces FEV1 and FVC significantly less than a nonselective beta-blocker, propranolol, at equivalent beta 1 -receptor blocking doses. Hypertension: 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. Angina Pectoris: By blocking catecholamine-induced increases in heart rate, in velocity and extent of myocardial contraction, and in blood pressure, metoprolol reduces the oxygen requirements of the heart at any given level of effort, thus making it useful in the long-term management of angina pectoris. Heart Failure: The precise mechanism for the beneficial effects of beta-blockers in heart failure has not been elucidated.
Dosage & Administration
2 DOSAGE AND ADMINISTRATION • Administer once daily with food or after a meal. Titrate at weekly or longer intervals as needed and tolerated. ( 2 ) • Hypertension: Recommended starting dosage is 100 mg daily, in single or divided doses. ( 2.1 ) • Angina Pectoris: Recommended starting dosage is 100 mg daily, given as two divided doses. ( 2.2 ) • Myocardial Infarction: The starting dosage depends upon tolerance of intravenous metoprolol, see full prescribing information. ( 2.3 ) 2.1 Hypertension Individualize the dosage of metoprolol tartrate tablets. Metoprolol tartrate tablets should be taken with or immediately following meals. The usual initial dosage is 100 mg daily in single or divided doses. Adjust dosage 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. The effective dosage range of metoprolol tartrate tablets is 100 mg to 450 mg per day. Dosages above 450 mg per day have not been studied. While once-daily dosing can maintain a reduction in blood pressure throughout the day, lower doses (especially 100 mg) may not maintain a full effect at the end of the 24-hour period. Larger or more frequent daily doses may be required. Measure blood pressure near the end of the dosing interval to determine whether satisfactory control is being maintained throughout the day. 2.2 Angina Pectoris The dosage of metoprolol tartrate tablets should be individualized. Metoprolol tartrate tablets should be taken with or immediately following meals. The usual initial dosage is 100 mg daily, given in two divided doses. Gradually increase the dosage at weekly intervals until optimum clinical response has been obtained or there is a pronounced slowing of the heart rate. The effective dosage range of metoprolol tartrate tablets is 100 to 400 mg per day. Dosages above 400 mg per day have not been studied. If treatment is to be discontinued, reduce the dosage gradually over a period of 1 to 2 weeks [see Warnings and Precautions (5.1)]. 2.3 Myocardial Infarction See prescribing information of intravenous metoprolol for dosage instructions for intravenous therapy. In patients who tolerate the full intravenous dose, initiate metoprolol tartrate tablets, 50 mg every 6 hours, 15 minutes after the last intravenous dose of metoprolol and continue for 48 hours. In the case of intolerance, reduce dose to 25 mg and administer for 48 hours. Titrate, based on tolerability, to a maintenance dosage of 100 mg twice daily. Continue therapy for at least 3 months. Although the efficacy of metoprolol tartrate beyond 3 months has not been conclusively established, data from studies with other beta-blockers suggest that treatment should be continued for 1 to 3 years.
Side Effects Overview
6 ADVERSE REACTIONS The following adverse reactions are described elsewhere in labeling: Worsening angina or myocardial infarction [see Warnings and Precautions (5)] Worsening heart failure [see Warnings and Precautions (5)]. Worsening AV block [see Contraindications (4)]. • Most common adverse reactions: tiredness, dizziness, depression, shortness of breath, bradycardia, hypotension, diarrhea, pruritus, rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Alembic Pharmaceuticals Limited at 1-866-210-9797 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Hypertension and Angina Most adverse effects have been mild and transient. Central Nervous System: Tiredness and dizziness have occurred in about 10% of patients. Depression has been reported in about 5 of 100 patients. Mental confusion and short-term memory loss have been reported. Headache, nightmares, and insomnia have also been reported. Cardiovascular: Shortness of breath and bradycardia have occurred in approximately 3% of patients. Cold extremities; arterial insufficiency, usually of the Raynaud type; palpitations; heart failure exacerbations; peripheral edema; and hypotension have been reported in about 1% of patients. Gangrene in patients with pre-existing severe peripheral circulatory disorders has also been reported [see Contraindications (4) and Warnings and Precautions (5.2)]. Respiratory: Wheezing (bronchospasm) and dyspnea have been reported in about 1% of patients [see Warnings and Precautions (5.3)]. Rhinitis has also been reported. Gastrointestinal: Diarrhea has occurred in about 5% of patients. Nausea, dry mouth, gastric pain, constipation, flatulence, and heartburn have been reported in about 1% of patients. Vomiting was a common occurrence. Hypersensitive Reactions: Pruritus or rash have occurred in about 5% of patients. Photosensitivity and worsening of psoriasis has been reported. Miscellaneous: Peyronie’s disease, musculoskeletal pain, blurred vision, and tinnitus has been reported. Myocardial Infarction In general, the adverse reactions observed in trials with metoprolol in MI are consistent with the hypertension and angina experience. In a randomized comparison of metoprolol tartrate and placebo in the setting of acute MI the following adverse reactions were reported: Metoprolol Tartrate Placebo Hypotension (systolic BP < 90 mm Hg) 27.4% 23.2% Bradycardia (heart rate < 40 beats/min) 15.9% 6.7% Second- or third-degree heart block 4.7% 4.7% First-degree heart block (P-R ≥ 0.26 sec) 5.3% 1.9% Heart failure 27.5% 29.6% 6.2 Post-Marketing Experience The following adverse reactions have been identified during post approval use of metoprolol tartrate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Central Nervous System: Reversible mental depression progressing to catatonia; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability, slightly clouded sensorium, and decreased performance on neuropsychometrics. Cardiovascular: Intensification of AV block [see Contraindications (4)]. Hematologic: Agranulocytosis, nonthrombocytopenic purpura and thrombocytopenic purpura. Hypersensitive Reactions: Fever combined with aching and sore throat, laryngospasm and respiratory distress. Laboratory Findings: Increase in blood triglycerides, elevated transaminase and decrease in High Density Lipoprotein (HDL)
Warnings & Precautions
5 WARNINGS AND PRECAUTIONS • Abrupt cessation may exacerbate myocardial ischemia. ( 5.1 ) • Heart Failure: Worsening cardiac failure may occur. ( 5.2 ) • Bronchospastic Disease: Avoid beta-blockers. ( 5.3 ) • Pheochromocytoma: Initiate therapy with an alpha blocker. ( 5.4 ) • Major Surgery: Avoid initiation of high-dose extended-release metoprolol in patients undergoing non-cardiac surgery. Do not routinely withdraw chronic beta-blocker therapy prior to surgery. ( 5.5 , 6.1 ) • Diabetes: May mask symptoms of hypoglycemia. ( 5.6 ) • Thyrotoxicosis: Abrupt withdrawal in patients with thyrotoxicosis might precipitate a thyroid storm. ( 5.7 ) • Peripheral Vascular Disease: Can aggravate symptoms of arterial insufficiency. ( 5.9 ) 5.1 Abrupt Cessation of Therapy Following abrupt cessation of therapy with certain beta-blocking agents, exacerbations of angina pectoris and, in some cases, myocardial infarction have occurred. When discontinuing chronically administered metoprolol tartrate, particularly in patients with ischemic heart disease, gradually reduce the dosage over a period of 1 to 2 weeks and monitor the patient. If angina markedly worsens or acute coronary ischemia develops, promptly reinstate metoprolol tartrate, and take measures appropriate for the management of unstable angina. Warn patients not to interrupt therapy without their physician’s advice. Because coronary artery disease is common and may be unrecognized, avoid abruptly discontinuing metoprolol tartrate in patients treated only for hypertension. 5.2 Heart Failure Worsening cardiac failure may occur during up-titration of metoprolol tartrate. If such symptoms occur, increase diuretics and restore clinical stability before advancing the dose of metoprolol tartrate [see Dosage and Administration (2)]. It may be necessary to lower the dose of metoprolol tartrate or temporarily discontinue it. Such episodes do not preclude subsequent successful titration of metoprolol tartrate. 5.3 Bronchospastic Disease Patients with bronchospastic disease, should in general, not receive beta-blockers, including metoprolol tartrate. Because of its relative beta 1 cardio-selectivity, however, metoprolol tartrate may be used in patients with bronchospastic disease who do not respond to, or cannot tolerate, other antihypertensive treatment. Because beta 1 -selectivity is not absolute, use the lowest possible dose of metoprolol tartrate. Bronchodilators, including beta 2 -agonists, should be readily available or administered concomitantly [see Dosage and Administration (2)]. 5.4 Pheochromocytoma If metoprolol tartrate 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. Administration of beta-blockers alone in the setting of pheochromocytoma has been associated with a paradoxical increase in blood pressure due to the attenuation of beta-mediated vasodilatation in skeletal muscle. 5.5 Major Surgery Avoid initiation of a high-dose regimen of beta-blocker therapy in patients undergoing non-cardiac surgery, since such use in patients with cardiovascular risk factors has been associated with bradycardia, hypotension, stroke and death. Chronically administered beta-blocking therapy should not be routinely withdrawn prior to major surgery, however, the impaired ability of the heart to respond to reflex adrenergic stimuli may augment the risks of general anesthesia and surgical procedures. 5.6 Hypoglycemia Beta-blockers may prevent early warning signs of hypoglycemia, such as tachycardia, and increase the risk for severe or prolonged hypoglycemia at any time during treatment, especially in patients with diabetes mellitus or children and patients who are fasting (i.e., surgery, not eating regularly, or are vomiting). If severe hypoglycemia occurs, patients should be instructed to seek emergency treatment. Beta-blockers may mask some of the manifestations of hypoglycemia, particularly tachycardia. 5.7 Thyrotoxicosis Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism, such as tachycardia. Abrupt withdrawal of beta-blockade may precipitate a thyroid storm. 5.8 Risk of Anaphylactic Reaction While taking beta-blockers, patients with a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated challenge, either accidental, diagnostic, or therapeutic. Such patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction. 5.9 Peripheral Vascular Disease Beta-blockers can precipitate or aggravate symptoms of arterial insufficiency in patients with peripheral vascular disease.
Contraindications
4 CONTRAINDICATIONS Metoprolol tartrate tablets are contraindicated in severe bradycardia, second-or third-degree heart block, cardiogenic shock, systolic blood pressure <100, decompensated heart failure, sick sinus syndrome (unless a permanent pacemaker is in place), and in patients who are hypersensitive to any component of this product. • Known hypersensitivity to product components. ( 4 ) • Severe bradycardia: Greater than first degree heart block, or sick sinus syndrome without a pacemaker. ( 4 ) • Cardiogenic shock or decompensated heart failure. ( 4 )
Pharmacokinetics
12.3 Pharmacokinetics Absorption: The estimated oral bioavailability of immediate release metoprolol is about 50% because of pre-systemic metabolism which is saturable leading to non-proportionate increase in the exposure with increased dose. Distribution: Metoprolol is extensively distributed with a reported volume of distribution of 3.2 to 5.6 L/kg. About 10% of metoprolol in plasma is bound to serum albumin. Metoprolol is known to cross the placenta and is found in breast milk. Metoprolol is also known to cross the blood brain barrier following oral administration and CSF concentrations close to that observed in plasma have been reported. Metoprolol is not a significant P-glycoprotein substrate. Elimination: Elimination of metoprolol tartrate is mainly by biotransformation in the liver. The mean elimination half-life of metoprolol is 3 to 4 hours; in poor CYP2D6 metabolizers the half-life may be 7 to 9 hours. Metabolism: Metoprolol tartrate is primarily metabolized by CYP2D6. Metoprolol is a racemic mixture of R-and S-enantiomers, and when administered orally, it exhibits stereoselective metabolism that is dependent on oxidation phenotype. CYP2D6 is absent (poor metabolizers) in about 8% of Caucasians and about 2% of most other populations. Poor CYP2D6 metabolizers exhibit severalfold higher plasma concentrations of metoprolol tartrate than extensive metabolizers with normal CYP2D6 activity thereby decreasing metoprolol tartrate’s cardioselectivity. Excretion Approximately 95% of the dose can be recovered in urine. In most subjects (extensive metabolizers), less than 5% of an oral dose and less than 10% of an intravenous dose are excreted as unchanged drug in the urine. In poor metabolizers, up to 30% or 40% of oral or intravenous doses, respectively, may be excreted unchanged; the rest is excreted by the kidneys as metabolites that appear to have no beta-blocking activity. The renal clearance of the stereo-isomers does not exhibit stereo-selectivity in renal excretion. Specific populations Geriatric patients: The geriatric population may show slightly higher plasma concentrations of metoprolol as a combined result of a decreased metabolism of the drug in elderly population and a decreased hepatic blood flow. However, this increase is not clinically significant or therapeutically relevant. Renal impairment : The systemic availability and half-life of metoprolol tartrate in patients with renal failure do not differ to a clinically significant degree from those in normal subjects. Hepatic Impairment: Since the drug is primarily eliminated by hepatic metabolism, hepatic impairment may impact the pharmacokinetics of metoprolol. Drug Interactions Metoprolol is metabolized predominantly by CYP2D6. In healthy subjects with CYP2D6 extensive metabolizer phenotype, coadministration of quinidine 100 mg, a potent CYP2D6 inhibitor, and immediate-release metoprolol 200 mg tripled the concentration of S-metoprolol and doubled the metoprolol elimination half-life. In four patients with cardiovascular disease, coadministration of propafenone 150 mg t.i.d. with immediate-release metoprolol 50 mg t.i.d. increased the steady-state metoprolol concentration 2-to 5-fold compared to metoprolol alone. Extensive metabolizers who concomitantly use CYP2D6 inhibiting drugs will have increased (several-fold) metoprolol blood levels, decreasing metoprolol's cardioselectivity [see Drug Interactions (7.2)] .