AMIODARONE HYDROCHLORIDE

Amiodarone Hydrochloride Injection contains Amiodarone Hydrochloride (C 25 H 29 I 2 NO 3 •HCl), a class III antiarrhythmic drug. Amiodarone Hydrochloride is (2-butyl-3-benzo-furanyl)[4-[2-(diethylamino)ethoxy]-3,5-diiodophenyl]methanone hydrochloride. Amiodarone Hydrochloride has the following structural formula: Amiodarone Hydrochloride is a white to slightly yellow crystalline powder, and is very slightly soluble in water. It has a molecular weight of 681.78 and contains 37.3% iodine by weight. Amiodarone Hydrochloride Injection is a sterile clear, pale-yellow micellar solution visually free from particulates. Each milliliter of the amiodarone formulation contains 50 mg of amiodarone hydrochloride, 20.2 mg of benzyl alcohol, 100 mg of polysorbate 80, and water for injection. Amiodarone Hydrochloride Injection contains polysorbate 80, which is known to leach di-(2-ethylhexyl)phthalate (DEHP) from polyvinylchloride (PVC) [(see Dosage and Administration ( 2 )] . Chemical Structure

Amiodarone Hydrochloride Injection, USP 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 Hydrochloride Injection, USP 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 Hydrochloride Injection, USP patients may be transferred to oral amiodarone therapy [see Dosage and Administration ( 2 )] . Use Amiodarone Hydrochloride Injection, USP for acute treatment until the patient's ventricular arrhythmias are stabilized. Most patients will require this therapy for 48 to 96 hours, but Amiodarone Hydrochloride Injection may be safely administered for longer periods if necessary. Amiodarone Hydrochloride Injection, USP 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 )

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) Maintenance infusion 540 mg over the REMAINING 18 hours (0.5 mg/min). Decrease the rate of the slow loading infusion to 0.5 mg/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 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 injection, is also known to leach DEHP from PVC [see Description ( 11 )] . Amiodarone does not need to be protected from light during administration. NOTE: Inspect parenteral drug products for particulate matter and discoloration prior to administration, whenever solution and container permit. Table 2: AMIODARONE HYDROCHLORIDE SOLUTION STABILITY Solution Concentration (mg/mL) Container Comments 5% Dextrose in Water (D 5 W) 1 to 6 PVC Physically compatible, with amiodarone loss <10% at 2 hours at room temperature. 5% Dextrose in Water (D 5 W) 1 to 6 Polyolefin, Glass Physically compatible, with no amiodarone loss at 24 hours at room temperature. Admixture Incompatibility Amiodarone in D 5 W is incompatible with the drugs shown in Table 3. Table 3: Y-SITE INJECTION INCOMPATIBILITY Drug Vehicle Amiodarone Concentration Comments Aminophylline D 5 W 4 mg/mL Precipitate Cefamandole Nafate D 5 W 4 mg/mL Precipitate Cefazolin Sodium D 5 W 4 mg/mL Precipitate Mezlocillin Sodium D 5 W 4 mg/mL Precipitate Heparin Sodium D 5 W -- Precipitate Sodium Bicarbonate D 5 W 3 mg/mL Precipitate Intravenous to Oral Transition Patients whose arrhythmias have been suppressed by amiodarone may be switched to oral amiodarone. When changing to oral amiodarone therapy, clinical monitoring is recommended, particularly for elderly patients. See package insert for oral amiodarone. Since grapefruit juice is known to inhibit CYP3A-mediated metabolism of oral amiodarone in the intestinal mucosa, resulting in increased plasma levels of amiodarone, do not drink grapefruit juice during treatment with oral amiodarone [see Drug Interactions ( 7 )] . Table 4 provides suggested doses of oral amiodarone to be initiated after varying durations of amiodarone administration. These recommendations are made on the basis of a similar total body amount of amiodarone delivered by the intravenous and oral routes, based on 50% bioavailability of oral amiodarone. Table 4: RECOMMENDATIONS FOR ORAL DOSAGE AFTER INTRAVENOUS INFUSION Duration of Amiodarone Infusion Assuming a 720 mg/day infusion (0.5 mg/min). Initial Daily Dose of Oral Amiodarone < 1 week 800 to 1600 mg 1-3 weeks 600 to 800 mg > 3 weeks Intravenous amiodarone is not intended for maintenance treatment. 400 mg The recommended starting dose is about 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen ( 2 ): -Initial Load: 150 mg per 100 mL (in D 5 W) infused over 10 minutes -Followed by: 1 mg/min for 6 hours -Followed by: 0.5 mg/min thereafter In the event of breakthrough episodes of VF or hemodynamically unstable VT ( 2 ): -Repeat the Initial Load described above as needed (infused over 10 minutes) Increase the rate of the maintenance infusion to achieve effective arrhythmia suppression. ( 2 )

Amiodarone is contraindicated in patients with: Known hypersensitivity to any of the components of amiodarone, 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.

The most common adverse reactions (1-2%) 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 (TdP), congestive heart failure, and liver function test abnormalities. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Hikma Pharmaceuticals USA Inc. at 1-877-233-2001, 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 Postmarketing Experience The following adverse reactions have been identified during post-approval use of amiodarone. 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. Body as a Whole: anaphylactic/anaphylactoid reaction (including shock), fever Cardiovascular: hypotension (sometimes fatal), sinus arrest Dermatologic: toxic epidermal necrolysis (sometimes fatal), exfoliative dermatitis, erythema multiforme, Stevens-Johnson syndrome, skin cancer, pruritus, angioedema Endocrine: syndrome of inappropriate antidiuretic hormone secretion (SIADH) Hematologic: pancytopenia, neutropenia, hemolytic anemia, aplastic anemia, thrombocytopenia, agranulocytosis, granuloma Hepatic: hepatitis, cholestatic hepatitis, cirrhosis Injection Site Reactions: pain, erythema, edema, pigment changes, venous thombosis, phlebitis, thrombophlebitis, cellulitis, necrosis, and skin sloughing Musculoskeletal: myopathy, muscle weakness, rhabdomyolysis Nervous System: hallucination, confusional state, disorientation, and delirium, pseudotumor cerebri Pancreatic: pancreatitis Renal: renal impairment, renal insufficiency, acute renal failure Respiratory: bronchospasm, possibly fatal respiratory disorders (including distress, failure, arrest and ARDS), bronchiolitis obliterans organizing pneumonia (possibly fatal), dyspnea, cough, hemoptysis, wheezing, hypoxia, pulmonary infiltrates, and /or mass, pleuritis Thyroid: thyroid nodules/thyroid cancer Vascular: vasculitis

Amiodarone is metabolized to the active metabolite desethylamiodarone by the cytochrome P450 (CYP450) enzyme group, specifically cytochromes P4503A4 (CYP3A) and CYP2C8. The CYP3A isoenzyme is present in both the liver and intestines. Amiodarone is an inhibitor of CYP3A. Therefore, amiodarone has the potential for interactions with drugs or substances that may be substrates, inhibitors or inducers of CYP3A. While only a limited number of in vivo drug-drug interactions with amiodarone have been reported, chiefly with the oral formulation, the potential for other interactions should be anticipated. This is especially important for drugs associated with serious toxicity, such as other antiarrhythmics. If such drugs are needed, reassess their dose and, where appropriate, measure plasma concentrations. In view of the long and variable half-life of amiodarone, potential for drug interactions exists not only with concomitant medication but also with drugs administered after discontinuation of amiodarone. Since amiodarone is a substrate for CYP3A and CYP2C8, drugs/substances that inhibit these isoenzymes may decrease the metabolism and increase serum concentration of amiodarone. Reported examples include the following: Protease inhibitors: Protease inhibitors are known to inhibit CYP3A to varying degrees. A case report of one patient taking amiodarone 200 mg and indinavir 800 mg three times a day resulted in increases in amiodarone concentrations from 0.9 mg/L to 1.3 mg/L. DEA concentrations were not affected. There was no evidence of toxicity. Consider monitoring for amiodarone toxicity and serial measurement of amiodarone serum concentration during concomitant protease inhibitor therapy. Histamine H 1 antagonists: Loratadine , a non-sedating antihistaminic, is metabolized primarily by CYP3A. QT interval prolongation and TdP have been reported with the coadministration of loratadine and amiodarone. Histamine H 2 antagonists: Cimetidine inhibits CYP3A and can increase serum amiodarone levels. Antidepressants: Trazodone , an antidepressant, is metabolized primarily by CYP3A. QT interval prolongation and TdP have been reported with the coadministration of trazodone and amiodarone. Other substances: Grapefruit juice given to healthy volunteers increased amiodarone AUC by 50% and C max by 84%, resulting in increased plasma levels of amiodarone. Do not take grapefruit juice during treatment with amiodarone. Amiodarone inhibits p-glycoprotein and certain CYP450 enzymes, including CYP1A2, CYP2C9, CYP2D6, and CYP3A. This inhibition can result in unexpectedly high plasma levels of other drugs which are metabolized by those CYP450 enzymes or are substrates for p-glycoprotein. Reported examples of this interaction include the following: Immunosuppressives: Cyclosporine (CYP3A substrate) administered in combination with oral amiodarone has been reported to produce persistently elevated plasma concentrations of cyclosporine resulting in elevated creatinine, despite reduction in dose of cyclosporine. HMG-CoA Reductase Inhibitors: Simvastatin (CYP3A substrate) in combination with amiodarone has been associated with reports of myopathy/rhabdomyolysis. Cardiovasculars: Cardiac glycosides : In patients receiving digoxin therapy, administration of oral amiodarone regularly results in an increase in serum digoxin concentration that may reach toxic levels with resultant clinical toxicity. Amiodarone taken concomitantly with digoxin increases the serum digoxin concentration by 70% after one day. On administration of oral amiodarone, review the need for digitalis therapy and reduce the dose of digitalis by approximately 50% or discontinue digitalis. If digitalis treatment is continued, monitor serum levels closely and observe patients for clinical evidence of toxicity. Antiarrhythmics: Other antiarrhythmic drugs, such as quinidine, procainamide, disopyramide, and phenytoin, have been used concurrently with amiodarone. There have been case reports of increased steady-state levels of quinidine, procainamide, and phenytoin during concomitant therapy with amiodarone. Phenytoin decreases serum amiodarone levels. Amiodarone taken concomitantly with quinidine increases quinidine serum concentration by 33% after two days. Amiodarone taken concomitantly with procainamide for less than seven days increases plasma concentrations of procainamide and n-acetyl procainamide by 55% and 33%, respectively. Reduce quinidine and procainamide doses by one-third when either is administered with amiodarone. Plasma levels of flecainide have been reported to increase in the presence of oral amiodarone; adjust the dose of flecainide when these drugs are administered concomitantly. In general, initiate any added antiarrhythmic drug at a lower than usual dose and monitor the patient carefully. Reserve the combination of amiodarone with other antiarrhythmic therapy to patients with life-threatening ventricular arrhythmias who are incompletely responsive to a single agent or incompletely responsive to amiodarone. During transfer to oral amiodarone, reduce the dose levels of previously administered 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. If the treatment is continued, carefully monitor these patients for adverse effects, especially for conduction disturbances and exacerbation of tachyarrhythmias. In amiodarone-treated patients who require additional antiarrhythmic therapy, the initial dose of such agents should be approximately half of the usual recommended dose. Antihypertensives: Use amiodarone with caution in patients receiving ß-receptor blocking agents (e.g., propranolol , a CYP3A inhibitor) or calcium channel antagonists (e.g., verapamil , a CYP3A substrate, and diltiazem , a CYP3A inhibitor) because of the possible potentiation of bradycardia, sinus arrest, and AV block; if necessary, amiodarone can continue to be used after insertion of a pacemaker in patients with severe bradycardia or sinus arrest. 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 the prothrombin time by 100% after 3 to 4 days, reduce the dose of the anticoagulant by one-third to one-half, and monitor prothrombin times closely. Clopidogrel , an inactive thienopyridine prodrug, is metabolized in the liver by CYP3A to an active metabolite. A potential interaction between clopidogrel and amiodarone resulting in ineffective inhibition of platelet aggregation has been reported. Some drugs/substances are known to accelerate the metabolism of amiodarone by stimulating the synthesis of CYP3A (enzyme induction). This may lead to low amiodarone serum levels and potential decrease in efficacy. Reported examples of this interaction include the following: Antibiotics: Rifampin is a potent inducer of CYP3A. Administration of rifampin concomitantly with oral amiodarone has been shown to result in decreases in serum concentrations of amiodarone and desethylamiodarone. Other substances, including herbal preparations: St. John's Wort ( Hypericum perforatum ) induces CYP3A. Since amiodarone is a substrate for CYP3A, St. John's Wort likely reduces amiodarone levels. Other reported interactions with amiodarone: Fentanyl (CYP3A substrate) in combination with amiodarone may cause hypotension, bradycardia, and decreased cardiac output. Sinus bradycardia has been reported with oral amiodarone in combination with lidocaine (CYP3A substrate) given for local anesthesia. Seizure, associated with increased lidocaine concentrations, has been reported with concomitant administration of intravenous amiodarone. Dextromethorphan is a substrate for both CYP2D6 and CYP3A. Amiodarone inhibits CYP2D6. Cholestyramine increases enterohepatic elimination of amiodarone and may reduce its serum levels and t ½ . Disopyramide causes QT prolongation which could induce arrhythmia. Fluoroquinolones, macrolide antibiotics, and azoles are known to cause QTc prolongation. There have been reports of QTc prolongation, with or without TdP, in patients taking amiodarone when fluoroquinolones, macrolide antibiotics, or azoles were administered concomitantly [see Warnings and Precautions ( 5.4 )] . Hemodynamic and electrophysiologic interactions have also been observed after concomitant administration with propranolol, diltiazem, and verapamil . Volatile Anesthetic Agents : Patients who are on amiodarone therapy may be more sensitive to the myocardial depressant and conduction defects of halogenated inhalational anesthetics [see Warnings and Precautions ( 5.9 )] . In addition to the interactions noted above, chronic (> 2 weeks) oral amiodarone administration impairs metabolism of phenytoin, dextromethorphan, and methotrexate. Since amiodarone is a substrate for CYP3A and CYP2C8, drugs/substances that inhibit these isoenzymes may decrease the metabolism and increase serum concentration of amiodarone. Amiodarone inhibits p-glycoprotein and certain CYP450 enzymes, including CYP1A2, CYP2C9, CYP2D6, and CYP3A. This inhibition can result in unexpectedly high plasma levels of other drugs that are metabolized by those CYP450 enzymes or are substrates for p-glycoprotein. Fluoroquinolones, macrolide antibiotics, and azoles are known to cause QTc prolongation. There have been reports of QTc prolongation, with or without TdP, in patients taking amiodarone when fluoroquinolones, macrolide antibiotics, or azoles were administered concomitantly. ( 7 )