Amiodarone Hydrochloride

1 INDICATIONS AND USAGE Amiodarone hydrochloride injection is indicated for initiation of treatment and prophylaxis of frequently recurring ventricular fibrillation (VF) and hemodynamically unstable ventricular tachycardia (VT) in patients refractory to other therapy. Amiodarone also can be used to treat patients with VT/VF for whom oral amiodarone is indicated, but who are unable to take oral medication. During or after treatment with amiodarone, patients may be transferred to oral amiodarone therapy [see Dosage and Administration (2) ] . Use amiodarone for acute treatment until the patient's ventricular arrhythmias are stabilized. Most patients will require this therapy for 48 to 96 hours, but amiodarone may be safely administered for longer periods if necessary. Amiodarone hydrochloride injection is an antiarrhythmic agent indicated for initiation of treatment and prophylaxis of frequently recurring ventricular fibrillation (VF) and hemodynamically unstable ventricular tachycardia (VT) in patients refractory to other therapy. ( 1 )

2 DOSAGE AND ADMINISTRATION Amiodarone shows considerable interindividual variation in response. Although a starting dose adequate to suppress life-threatening arrhythmias is needed, close monitoring with adjustment of dose is essential. The recommended starting dose of amiodarone is about 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen: Table 1: AMIODARONE DOSE RECOMMENDATIONS: FIRST 24 HOURS Loading Infusions First Rapid: 150 mg over the FIRST 10 minutes (15 mg/min). Add 3 mL of amiodarone (150 mg) to 100 mL D 5 W (concentration = 1.5 mg/mL). Infuse 100 mL over 10 minutes. Followed by Slow: 360 mg over the NEXT 6 hours (1 mg/min). Add 18 mL of amiodarone (900 mg) to 500 mL D 5 W (concentration = 1.8 mg/mL). Infuse 200 mL at a rate of 0.556 mL/min. Maintenance Infusion 540 mg over the REMAINING 18 hours (0.5 mg/min). Decrease the rate of the slow loading infusion to 0.278 mL/min. After the first 24 hours, continue the maintenance infusion rate of 0.5 mg/min (720 mg per 24 hours) utilizing a concentration of 1 mg/mL to 6 mg/mL (Use a central venous catheter for amiodarone concentrations greater than 2 mg/mL). The rate of the maintenance infusion may be increased to achieve effective arrhythmia suppression. In the event of breakthrough episodes of VF or hemodynamically unstable VT, use 150 mg supplemental infusions of amiodarone (mixed in 100 mL of D 5 W and infused over 10 minutes to minimize the potential for hypotension). The first 24-hour dose may be individualized for each patient; however, in controlled clinical trials, mean daily doses above 2100 mg were associated with an increased risk of hypotension. Do not exceed an initial infusion rate of 30 mg/min. Based on the experience from clinical studies of intravenous amiodarone, a maintenance infusion of up to 0.5 mg/min can be continued for 2 to 3 weeks regardless of the patient's age, renal function, or left ventricular function. There has been limited experience in patients receiving intravenous amiodarone for longer than 3 weeks. The surface properties of solutions containing injectable amiodarone are altered such that the drop size may be reduced. This reduction may lead to underdosage of the patient by up to 30% if drop counter infusion sets are used. Amiodarone must be delivered by a volumetric infusion pump. Administer amiodarone, whenever possible, through a central venous catheter dedicated to that purpose. Use an in-line filter during administration. Intravenous amiodarone loading infusions at much higher concentrations and rates of infusion much faster than recommended have resulted in hepatocellular necrosis and acute renal failure, leading to death [see Warnings and Precautions (5.3) ] . Intravenous amiodarone concentrations greater than 3 mg/mL in D 5 W have been associated with a high incidence of peripheral vein phlebitis; however, concentrations of 2.5 mg/mL or less appear to be less irritating. Therefore, for infusions longer than 1 hour, do not exceed amiodarone concentrations of 2 mg/mL, unless a central venous catheter is used [see Adverse Reactions (6.2) ] . Amiodarone infusions exceeding 2 hours must be administered in glass or polyolefin bottles containing D 5 W. Do not use evacuated glass containers for admixing, as incompatibility with a buffer in the container may cause precipitation. Amiodarone adsorbs to polyvinyl chloride (PVC) tubing, but all of the clinical experience has been with PVC tubing and the concentrations and rates of infusion provided in DOSAGE AND ADMINISTRATION reflect dosing in these studies. Amiodarone has been found to leach out plasticizers, including DEHP [di-(2-ethylhexyl)phthalate] from intravenous tubing (including PVC tubing). The degree of leaching increases when infusing amiodarone at higher concentrations and lower flow rates than provided in DOSAGE AND ADMINISTRATION. Polysorbate 80, a component of amiodarone hydrochloride injection, is also known to leach DEHP from PVC [see …

5 WARNINGS AND PRECAUTIONS Amiodarone should be administered only by physicians who are experienced in the treatment of life-threatening arrhythmias, who are thoroughly familiar with the risks and benefits of amiodarone therapy, and who have access to facilities adequate for monitoring the effectiveness and side effects of treatment. Because of the long half-life of amiodarone and its metabolite desethylamiodarone, the potential for adverse reactions or interactions, as well as observed adverse effects, can persist following amiodarone withdrawal. • Hypotension: Slow the infusion; as needed, add vasopressor drugs, positive inotropic agents, and volume expansion. ( 5.1 ) • Bradycardia and AV block: Slow the infusion or discontinue. ( 5.2 ) 5.1 Hypotension Hypotension is the most common adverse reaction seen with intravenous amiodarone. In clinical trials, treatment-emergent, drug-related hypotension was reported as an adverse effect in 288 (16%) of 1836 patients treated with intravenous amiodarone. Clinically significant hypotension during infusions was seen most often in the first several hours of treatment and was not dose related, but appeared to be related to the rate of infusion. Hypotension necessitating alterations in intravenous amiodarone therapy was reported in 3% of patients, with permanent discontinuation required in less than 2% of patients. Treat hypotension initially by slowing the infusion; additional standard therapy may be needed, including the following: vasopressor drugs, positive inotropic agents, and volume expansion. Monitor the initial rate of infusion closely and do not exceed the recommended rate [see Dosage and Administration (2) ] . In some cases, hypotension may be refractory and result in a fatal outcome [see Adverse Reactions (6.2) ] . 5.2 Bradycardia and Atrio-ventricular Block In 90 (4.9%) of 1836 patients in clinical trials, drug-related bradycardia that was not dose-related occurred while they were receiving intravenous amiodarone for life-threatening VT/VF. Treat bradycardia by slowing the infusion rate or discontinuing amiodarone. In some patients, a pacemaker is required. Despite such measures, bradycardia was progressive and terminal in 1 patient during the controlled trials. Treat patients with a known predisposition to bradycardia or AV block with amiodarone in a setting where a temporary pacemaker is available. 5.3 Hepatic Injury Elevations of blood hepatic enzyme values [alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT)] are commonly seen in patients with immediately life-threatening VT/VF. Interpreting elevated AST activity can be difficult because the values may be elevated in patients who have had recent myocardial infarction, congestive heart failure, or multiple electrical defibrillations. Approximately 54% of patients receiving intravenous amiodarone in clinical studies had baseline liver enzyme elevations, and 13% had clinically significant elevations. In 81% of patients with both baseline and on-therapy data available, the liver enzyme elevations either improved during therapy or remained at baseline levels. Baseline abnormalities in hepatic enzymes are not a contraindication to treatment. Elevated bilirubin levels have been reported in patients administered intravenous amiodarone. Acute, centrolobular confluent hepatocellular necrosis leading to hepatic coma, acute renal failure, and death has been associated with the administration of intravenous amiodarone [see Dosage and Administration (2) ] . In patients with life-threatening arrhythmias, the potential risk of hepatic injury should be weighed against the potential benefit of amiodarone therapy. Carefully monitor patients receiving amiodarone for evidence of progressive hepatic injury. In such cases, consider reducing the rate of administration or withdrawing amiodarone. 5.4 Proarrhythmia Like all antiarrhythmic agents, amiodarone may cause a worsening of existing arrhyth…

4 CONTRAINDICATIONS Amiodarone is contraindicated in patients with: • Known hypersensitivity to any of the components of amiodarone hydrochloride injection, including iodine. Hypersensitivity reactions may involve rash, angioedema, cutaneous/mucosal hemorrhage (bleeding), fever, arthralgias (joint pains), eosinophilia (abnormal blood counts), urticaria (hives), thrombotic thrombocytopenic purpura, or severe periarteritis (inflammation around blood vessels). • Cardiogenic shock • Marked sinus bradycardia • Second- or third-degree atrio-ventricular (AV) block unless a functioning pacemaker is available. Amiodarone is contraindicated in patients with ( 4 ): • Known hypersensitivity to any of the components of amiodarone, including iodine • Cardiogenic shock • Marked sinus bradycardia • Second- or third-degree atrio-ventricular (AV) block unless a functioning pacemaker is available.

7 DRUG INTERACTIONS • Amiodarone is a substrate for CYP3A and CYP2C8, so inhibitors and inducers affect amiodarone exposure ( 7 ) • Amiodarone inhibits p-glycoprotein and CYP1A2, CYP2C9, CYP2D6, and CYP3A, increasing exposure to other drugs ( 7 ) 7.1 Pharmacodynamic Interactions Drugs Prolonging the QT Interval Co-administration of drugs prolonging the QT interval (such as class I and III antiarrhythmics, lithium, certain phenothiazines, tricyclic antidepressants, certain fluoroquinolone and macrolide antibiotics, azole antifungals, halogenated inhalation anesthetic agents) increases the risk of Torsade de Pointes. In general, avoid concomitant use of drugs that prolong the QT interval [see Warnings and Precautions (5.4) ] . Drugs That Slow Heart Rate Concomitant use of drugs with depressant effects on the sinus and AV nodes (e.g., digoxin, beta blockers, verapamil, diltiazem, ivabradine, clonidine) can potentiate the electrophysiologic and hemodynamic effects of amiodarone, resulting in bradycardia, sinus arrest, and AV block. Monitor heart rate in patients on amiodarone and concomitant drugs that slow heart rate. 7.2 Pharmacokinetic Interactions Effect of Other Drugs on Amiodarone Amiodarone is metabolized to the active metabolite desethylamiodarone (DEA) by the cytochrome P450 (CYP450) enzyme group, specifically CYP3A and CYP2C8. Amiodarone has the potential for interactions with drugs or substances that may be substrates, inhibitors or inducers of CYP450 enzymes (e.g., inhibitors such as protease inhibitors , grapefruit juice , certain fluoroquinolone and macrolide antibiotics , azole antifungals and inducers such as St. John’s Wort ) or P-glycoprotein. In view of the long and variable half- life of amiodarone, potential for drug interactions exists not only with concomitant medications but also with drugs administered after discontinuation of amiodarone [see Clinical Pharmacology (12.3) ] . Patients should avoid grapefruit juice beverages while taking amiodarone because exposure to amiodarone is significantly increased [see Clinical Pharmacology (12.3) ] . Effect of Amiodarone on Other Drugs Amiodarone and DEA are inhibitors of P-glycoprotein and certain CYP450 enzymes, including CYP1A2, CYP2C9, CYP2D6, and CYP3A [see Clinical Pharmacology (12.3) ] . Antiarrhythmics The metabolism of quinidine , procainamide , and flecainide can be inhibited by amiodarone. In general, initiate any added antiarrhythmic drug at a lower than usual dose and monitor the patient carefully. During transfer to oral amiodarone, reduce the dose levels of previously administered antiarrhythmic agents by 30% to 50% several days after the addition of oral amiodarone. Review the continued need for the other antiarrhythmic agent after the effects of amiodarone have been established, and attempt discontinuation [see Clinical Pharmacology (12.3) ]. Digoxin In patients receiving digoxin therapy, administration of oral amiodarone results in an increase in serum digoxin concentration. Reduce dose of digoxin by half or discontinue digoxin. If digitalis treatment is continued, monitor serum levels closely and observe patients for clinical evidence of toxicity [see Clinical Pharmacology (12.3) ] . HMG-CoA Reductase Inhibitors Limit the dose of simvastatin in patients on amiodarone to 20 mg daily. Limit the daily dose of lovastatin to 40 mg. Lower starting and maintenance doses of other CYP3A4 substrates (e.g., atorvastatin) may be required as amiodarone may increase the plasma concentration of these drugs. Anticoagulants Potentiation of warfarin -type (CYP2C9 and CYP3A substrate) anticoagulant response is almost always seen in patients receiving amiodarone and can result in serious or fatal bleeding. Since the concomitant administration of warfarin with amiodarone increases INR by 100% after 3 to 4 days, reduce the dose of the anticoagulant by one-third to one-half, and monitor INR closely. Cyclosporine (CYP3A Substrate) Administered in combination with oral am…

8.1 Pregnancy Pregnancy Category D [see Warnings and Precautions (5.8) ] . Teratogenic Effects Amiodarone and desethylamiodarone cross the placenta. Reported risks include: • neonatal bradycardia, QT prolongation, and periodic ventricular extrasystoles • neonatal hypothyroidism (with or without goiter) detected antenatally or in the newborn and reported even after a few days of exposure • neonatal hyperthyroxinemia • neurodevelopmental abnormalities independent of thyroid function, including speech delay and difficulties with written language and arithmetic, delayed motor development, and ataxia. • jerk nystagmus with synchronous head titubation • fetal growth retardation • premature birth Amiodarone has caused a variety of adverse effects in animals. Amiodarone was given intravenously to rabbits at dosages of 5 mg/kg per day, 10 mg/kg per day, or 25 mg/kg per day (about 0.1, 0.3, and 0.7 times the human intravenous maintenance dose of 0.5 mg/min on a body surface area basis), during gestation days 8 to 16 (organogenesis). The incidence of maternal deaths increased with increasing dose and occurred in all treated groups, and controls. Mean fetal weights were significantly decreased in the low and middle dose groups and embryotoxicity (as manifested by fewer full- term fetuses and increased resorptions) occurred at dosages of 10 mg/kg and above. There were no significant differences in the number of minor fetal abnormalities and no major fetal abnormalities were observed. Amiodarone was administered by continuous intravenous infusion to rats at dosages of 25 mg/kg per day, 50 mg/kg per day, or 100 mg/kg per day (about 0.3, 0.7, and 1.3 times the human intravenous maintenance dose of 0.5 mg/min on a body surface area basis) during gestation days 8 to 16 (organogenesis). Maternal toxicity (manifest as reduced weight gain and food consumption) and embryotoxicity (manifest as increased resorptions, decreased live litter size and fetal body weights, and delayed sternal and metacarpal ossification) were observed in the 100 mg/kg group. The delayed ossification was reversible and related to decreased fetal weight. Fetal thyroid tissues appeared normal in all groups. Nonteratogenic Effects Very high concentrations of amiodarone and desethylamiodarone may be found in testes. Elevated follicle-stimulating hormone and luteinizing hormone levels, suggestive of testicular dysfunction, have been reported in men on long-term amiodarone treatment. While planning pregnancy after discontinuation of amiodarone treatment, consider the long half-life of amiodarone and its metabolite DEA.

8.3 Nursing Mothers Amiodarone and one of its major metabolites, desethylamiodarone (DEA), are excreted in human milk, suggesting that breast-feeding could expose the nursing infant to a significant dose of the drug. Nursing offspring of lactating rats administered amiodarone have demonstrated reduced viability and reduced body weight gains. The risk of exposing the infant to amiodarone must be weighed against the potential benefit of arrhythmia suppression in the mother. Advise the mother to discontinue nursing.

6 ADVERSE REACTIONS The following adverse reactions are described elsewhere in labeling: • Hypotension [see Warnings and Precautions (5.1) ] • Hepatic injury [see Warnings and Precautions (5.3) ] • Rhythm disturbances [see Warnings and Precautions (5.4) ] • Pulmonary injury [see Warnings and Precautions (5.5) ] • Thyroid injury [see Warnings and Precautions (5.7) ] • Hypersensitivity [see Warnings and Precautions (5.11) ] • The most common adverse reactions (1% to 2%) leading to discontinuation of intravenous amiodarone therapy are hypotension, asystole/cardiac arrest/pulseless electrical activity, VT, and cardiogenic shock. ( 6 ) • Other important adverse reactions are, torsade de pointes, congestive heart failure, and liver function test abnormalities. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan at 1-877-446-3679 (1-877-4-INFO-RX) 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. In a total of 1836 patients in controlled and uncontrolled clinical trials, 14% of patients received intravenous amiodarone for at least one week, 5% received it for at least 2 weeks, 2% received it for at least 3 weeks, and 1% received it for more than 3 weeks, without an increased incidence of severe adverse reactions. The mean duration of therapy in these studies was 5.6 days; median exposure was 3.7 days. The most important adverse reactions were hypotension, asystole/cardiac arrest/pulseless electrical activity (PEA), cardiogenic shock, congestive heart failure, bradycardia, liver function test abnormalities, VT, and AV block. Overall, treatment was discontinued for about 9% of the patients because of adverse reactions. The most common adverse reactions leading to discontinuation of intravenous amiodarone therapy were hypotension (1.6%), asystole/cardiac arrest/PEA (1.2%), VT (1.1%), and cardiogenic shock (1%). Table 5 lists the most common (incidence ≥ 2%) adverse reactions during intravenous amiodarone therapy considered at least possibly drug-related. These data were collected in clinical trials involving 1836 patients with life-threatening VT/VF. Data from all assigned treatment groups are pooled because none of the adverse reactions appeared to be dose-related. Table 5: ADVERSE REACTIONS IN PATIENTS RECEIVING INTRAVENOUS AMIODARONE IN CONTROLLED AND OPEN-LABEL STUDIES (≥ 2% INCIDENCE) Study Event Controlled Studies (n = 814) Open-Label Studies (n = 1022) Total (n = 1836) Body as a whole Fever 24 (2.9%) 13 (1.2%) 37 (2.0%) Cardiovascular System Bradycardia 49 (6.0%) 41 (4.0%) 90 (4.9%) Congestive heart failure 18 (2.2%) 21 (2.0%) 39 (2.1%) Heart arrest 29 (3.5%) 26 (2.5%) 55 (2.9%) Hypotension 165 (20.2%) 123 (12.0%) 288 (15.6%) Ventricular tachycardia 15 (1.8%) 30 (2.9%) 45 (2.4%) Digestive System Liver function tests abnormal 35 (4.2%) 29 (2.8%) 64 (3.4%) Nausea 29 (3.5%) 43 (4.2%) 72 (3.9%) Other adverse reactions reported in less than 2% of patients receiving intravenous amiodarone in controlled and uncontrolled studies included the following: abnormal kidney function, atrial fibrillation, diarrhea, increased ALT, increased AST, lung edema, nodal arrhythmia, prolonged QT interval, respiratory disorder, shock, sinus bradycardia, Stevens-Johnson syndrome, thrombocytopenia, VF, and vomiting. 6.2 Post-Marketing Experience The following adverse reactions have been reported in the post-marketing experience during or in close temporal relationship to intravenous amiodarone administration. 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. Blood and Lymphatic System Disorders: pancytopenia, n…