Metoprolol Tartrate

1. INDICATIONS AND USAGE Metoprolol Tartrate Tablets is a beta-adrenergic blocker indicated in the treatment of hemodynamically stable adult patients with myocardial infarction, to reduce the risk of cardiovascular mortality. ( 1.1 )

1.1 Myocardial Infarction Metoprolol Tartrate Tablets is indicated in the treatment of hemodynamically stable adult patients with myocardial infarction (MI) to reduce cardiovascular mortality.

3. DOSAGE FORMS AND STRENGTHS Metoprolol Tartrate Tablets is supplied as a 12.5 mg tablet that is pink-colored, film coated, round, biconvex, debossed with “˄E” on one side, and plain on the other side. Tablets: 12.5 mg. of metoprolol tartrate ( 3 )

4. CONTRAINDICATIONS Metoprolol Tartrate Tablets is 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. Severe bradycardia: Greater than first degree heart block, or sick sinus syndrome without a pacemaker. ( 4 ) Cardiogenic shock or decompensated heart failure. ( 4 ) Known hypersensitivity to product components. ( 4 )

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 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 Tablets, gradually reduce the dosage over a period of 1 to 2 weeks and monitor the patient. Warn patients not to interrupt therapy without their physician’s advice.

5.2 Heart Failure Worsening cardiac failure may occur during up-titration of Metoprolol Tartrate Tablets. If such symptoms occur, increase diuretics and restore clinical stability before advancing the dose of Metoprolol Tartrate Tablets [see Dosage and Administration (2) ]. It may be necessary to lower the dose of Metoprolol Tartrate Tablets or temporarily discontinue it. Such episodes do not preclude subsequent successful titration of Metoprolol Tartrate Tablets.

5.3 Bronchospastic Disease Patients with bronchospastic disease, should in general, not receive beta-blockers, including Metoprolol Tartrate Tablets. Because of its relative beta 1 cardio-selectivity, however, Metoprolol Tartrate Tablets may be used in patients with bronchospastic disease who do not respond to, or cannot tolerate, other antihypertensive treatment. Because beta1-selectivity is not absolute, use the lowest possible dose of Metoprolol Tartrate Tablets. Bronchodilators, including beta 2 -agonists, should be readily available or administered concomitantly [see Dosage and Administration (2) ].

5.4 Pheochromocytoma If Metoprolol Tartrate Tablets 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.

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 Reactions 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.

6. ADVERSE REACTIONS The following adverse reactions are described elsewhere in labeling: Worsening Ischemia with Abrupt Discontinuation [see Warnings and Precautions (5) ] Worsening heart failure [see Warnings and Precautions (5) ]. Worsening atrioventricular (AV) block [see Contraindications (4) ]. Most common adverse reactions in the setting of treatment of myocardial infarction are hypotension and bradycardia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Advagen Pharma Ltd, at +1 (866)-488-0312 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. Myocardial Infarction In a randomized comparison of Metoprolol Tartrate Tablets and placebo in the setting of acute MI [see Clinical studies 14.1 ] the following adverse reactions were reported: Adverse Reaction Metoprolol Tartrate Tablets N=698 % Placebo N=697 % 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 reported during post-approval use of Metoprolol Tartrate Tablets. 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 cognitive performance. Cardiovascular: Worsening 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)

7. DRUG INTERACTIONS Catecholamine-depleting drugs may have an additive effect when given with beta-blocking agents. ( 7.1 ) Patients may be unresponsive to the usual doses of epinephrine used to treat allergic reaction. ( 7.2 ) CYP2D6 Inhibitors are likely to increase metoprolol concentration. ( 7.3 ) Concomitant use of glycosides, clonidine, and diltiazem and verapamil with beta-blockers can increase the risk of bradycardia. ( 7.4 ) Beta-blockers including metoprolol, may exacerbate the rebound hypertension that can follow the withdrawal of clonidine. ( 7.4 )

7.1 Catecholamine Depleting Drugs Observe patients treated with Metoprolol Tartrate Tablets plus a catecholamine depletor for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension. Catecholamine depleting drugs (e.g., reserpine, monoamine oxidase (MAO) inhibitors) may have an additive effect when given with beta-blocking agents.

7.2 Epinephrine The cardiostimulating and bronchodilating effects of epinephrine are antagonized by beta-adrenergic blocking drugs, such as metoprolol. Higher doses of epinephrine might be necessary for patients taking metoprolol. 7.3 CYP2D6 Inhibitors Monitor patients closely when the combination use of CYP2D6 inhibitor and metoprolol cannot be avoided. Drugs that are strong inhibitors of CYP2D6 such as quinidine, fluoxetine, paroxetine, and propafenone were shown to double metoprolol concentrations. While there is no information about moderate or weak inhibitors, these may also increase metoprolol concentration. Increases in plasma concentration decrease the beta 1 cardioselectivity of metoprolol [see Clinical Pharmacology (12.3) ] .

7.4 Negative Chronotropes If clonidine and metoprolol are coadministered, withdraw the beta-blocker several days before the gradual withdrawal of clonidine because metoprolol may exacerbate the rebound hypertension that can follow the withdrawal of clonidine. If replacing clonidine with metoprolol, delay the introduction of metoprolol for several days after clonidine discontinuation. Digitalis glycosides, clonidine, diltiazem, and verapamil slow atrioventricular conduction and decrease heart rate. Concomitant use with beta blockers can increase the risk of bradycardia.

8. USE IN SPECIFIC POPULATIONS Hepatic Impairment: Consider initiating Metoprolol Tartrate Tablets therapy at low doses and gradually increase dosage to optimize therapy, while monitoring closely for adverse events. ( 8.6 )

8.1 Pregnancy Risk Summary Available data from published observational studies have not demonstrated an association of adverse developmental outcomes with maternal use of metoprolol during pregnancy (see Data ) . Untreated myocardial infarction during pregnancy can lead to adverse outcomes for the mother and the fetus (see Clinical Considerations ) . 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, approximately 11 times the daily dose of 450 mg in a 60-kg patient on a mg/m 2 basis. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. 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. Clinical consideration Fetal/Neonatal adverse reactions Metoprolol crosses the placenta. Neonates born to mothers who are receiving metoprolol during pregnancy, may be at risk for hypotension, hypoglycemia, bradycardia, and respiratory depression. Observe neonates and manage accordingly. Data Human Data Data from published observational studies did not demonstrate an association of major congenital malformations and use of metoprolol in pregnancy. The published literature has reported inconsistent findings of intrauterine growth retardation, preterm birth and perinatal mortality with maternal use of metoprolol during pregnancy; however, these studies have methodological limitations hindering interpretation. Methodological limitations include retrospective design, concomitant use of other medications, and other unadjusted confounders that may account for the study findings including the underlying disease in the mother. These observational studies cannot definitively establish or exclude any drug-associated risk during pregnancy. Animal Data Metoprolol has been shown to increase post-implantation loss and decrease neonatal survival in rats at oral dosages of 500 mg/kg/day, i.e. 11 times, on a mg/m 2 basis, the daily dose of 450 mg in a 60-kg patient. No fetal abnormalities were observed when pregnant rats received metoprolol orally up to a dose of 200 mg/kg/day, i.e. 4 times, the daily dose of 400mg in a 60-kg patient.

8.2 Lactation Risk Summary Limited available data from published literature report that metoprolol is present in human milk. The estimated daily infant dose of metoprolol received from breastmilk ranges from 0.05 mg to less than 1 mg. The estimated relative infant dosage was 0.5% to 2% of the mother's weight-adjusted dosage (see Data ). No adverse reactions of metoprolol on the breastfed infant have been identified. There is no information regarding the effects of metoprolol on milk production. Clinical consideration Monitoring for adverse reactions For a lactating woman who is a slow metabolizer of metoprolol, monitor the breastfed infant for bradycardia and other symptoms of beta blockade such as dry mouth, skin or eyes, diarrhea or constipation. In a report of 6 mothers taking metoprolol, none reported adverse effects in her breastfed infant. Data Limited published cases estimate the infant daily dose of metoprolol received from breast milk range from 0.05 mg to less than 1 mg. In 2 women who were taking unspecified amount of metoprolol, milk samples were taken after one dose of metoprolol. The estimated amount of metoprolol and alpha-hydroxymetoprolol in breast milk is reported to be less than 2% of the mother's weight-adjusted dosage. In a small study, breast milk was collected every 2 to 3 hours over one dosage interval, in three mothers (at least 3 months postpartum) who took metoprolol of unspecified amount. The average amount of metoprolol present in breast milk was 71.5 mcg/day (range 17.0 mcg to 158.7 mcg). The average relative infant dosage was 0.5% of the mother's weight-adjusted dosage.

8.3 Females and Males of Reproductive Potential Risk Summary Based on the published literature, beta blockers (including metoprolol) may cause erectile dysfunction and inhibit sperm motility. In animal fertility studies, metoprolol has been associated with reversible adverse effects on spermatogenesis starting at oral dose level of 3.5 mg/kg in rats, which would correspond to a dose of 34 mg/day in humans in mg/m 2 equivalent, although other studies have shown no effect of metoprolol on reproductive performance in male rats. No evidence of impaired fertility due to metoprolol was observed in rats [see Nonclinical Toxicology (13.1) ].

8.4 Pediatric Use Safety and effectiveness of Metoprolol Tartrate Tablets have not been established in pediatric patients.

8.5 Geriatric Use In worldwide clinical trials of Metoprolol Tartrate Tablets in myocardial infarction, where approximately 478 patients were over 65 years of age (0 over 75 years of age), no age-related differences in safety and effectiveness were found. Other reported clinical experience in myocardial infarction has not identified differences in response between the elderly and younger patients. In general, use a low initial starting dose in elderly patients given their greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

8.6 Hepatic Impairment No studies have been performed with Metoprolol Tartrate Tablets in patients with hepatic impairment. Metoprolol Tartrate Tablets is metabolized by the liver, metoprolol blood levels are likely to increase substantially with poor hepatic function. Therefore, initiate therapy at doses lower than those recommended; and increase doses gradually in patients with impaired hepatic function.

8.7 Renal Impairment The systemic availability and half-life of metoprolol in patients with renal failure do not differ to a clinically significant degree from those in normal subjects. No reduction in dosage is needed in patients with renal failure [see Clinical Pharmacology (12.3) ] .