Drug: Amiodarone HCl Injection

Amiodarone HCl Injection contains amiodarone HCl (C25H29I2NO3•HCl), a class III antiarrhythmic drug. Amiodarone HCl is (2-butyl-3-benzofuranyl)[4-[2-(diethylamino)ethoxy]-3,5-diiodophenyl]methanone hydrochloride. Amiodarone HCl has the following structural formula: Amiodarone HCl 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 HCl injection is a sterile clear, pale-yellow micellar solution visually free from particulates. Each milliliter of the amiodarone HCl injection formulation contains 50 mg of amiodarone HCl, 20.2 mg of benzyl alcohol NF, 100 mg of polysorbate 80 NF, and Water for Injection USP.Last reviewed on RxList: 11/18/2008
This monograph has been modified to include the generic and brand name in many instances.

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In a total of 1836 patients in controlled and uncontrolled clinical trials, 14% of patients received intravenous amiodarone for at least 1 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 treatment-emergent adverse effects were hypotension, asystole/cardiac arrest/electromechanical dissociation (EMD), 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 effects. The most common adverse effects leading to discontinuation of intravenous amiodarone therapy were hypotension (1.6%), asystole/cardiac arrest/EMD (1.2%), VT (1.1%), and cardiogenic shock (1%). The following table lists the most common (incidence > 2%) treatment-emergent adverse events during intravenous amiodarone therapy considered at least possibly drug-related. These data were collected from the Wyeth-Ayerst clinical trials involving 1836 patients with life-threatening VT/VF. Data from all assigned treatment groups are pooled because none of the adverse events appeared to be dose-related. SUMMARY TABULATION OF TREATMENT-EMERGENT DRUG-RELATED STUDY EVENTS 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 treatment-emergent possibly drug-related adverse events 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. Postmarketing Reports In postmarketing surveillance, hypotension (sometimes fatal), sinus arrest, pseudotumor cerebri, syndrome of inappropriate antidiuretic hormone secretion (SIADH), toxic epidermal necrolysis (sometimes fatal), exfoliative dermatitis, pancytopenia, neutropenia, erythema multiforme, angioedema, bronchospasm, possibly fatal respiratory disorders (including distress, failure, arrest, and ARDS), fever, dyspnea, cough, hemoptysis, wheezing, hypoxia, pulmonary infiltrates and anaphylactic/anaphylactoid reaction (including shock), hallucination, confusional state, disorientation, and delirium also have been reported with amiodarone therapy. Also, in patients receiving recommended dosages, there have been postmarketing reports of the following injection site reactions: pain, erythema, edema, pigment changes, venous thrombosis, phlebitis, thrombophlebitis, cellulitis, necrosis, and skin sloughing (see DOSAGE AND ADMINISTRATION). Read the Amiodarone HCl Injection (amiodarone hcl injection) Side Effects Center for a complete guide to possible side effectsLearn More »

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Amiodarone shows considerable inter-individual variation in response. Thus, although a starting dose adequate to suppress life-threatening arrhythmias is needed, close monitoring with adjustment of dose as needed is essential. The recommended starting dose of intravenous amiodarone is about 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen: AMIODARONE HCI INJECTION DOSE RECOMMENDATIONS
- FIRST 24 HOURS -
Loading infusions First Rapid: 150 mg over the FIRST 10 minutes (15 mg/min).   Add 3 mL of Amiodarone HCl Injection (150 mg) to 100 mL D5W (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 HCl Injection (900 mg) to 500 mL D5W (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, the maintenance infusion rate of 0.5 mg/min (720 mg/24 hours) should be continued utilizing a concentration of 1 to 6 mg/mL (amiodarone HCl injection concentrations greater than 2 mg/mL should be administered via a central venous catheter). In the event of breakthrough episodes of VF or hemodynamically unstable VT, 150 mg supplemental infusions of amiodarone HCl injection mixed in 100 mL of D5W may be administered. Such infusions should be administered over 10 minutes to minimize the potential for hypotension. The rate of the maintenance infusion may be increased to achieve effective arrhythmia suppression. 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. The initial infusion rate should not exceed 30 mg/min. Based on the experience from clinical studies of amiodarone injection, a maintenance infusion of up to 0.5 mg/min can be cautiously 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 amiodarone injection 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 injection must be delivered by a volumetric infusion pump. Amiodarone injection should, whenever possible, be administered through a central venous catheter dedicated to that purpose. An in-line filter should be used during administration. Amiodarone injection 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 PRECAUTIONS, Liver Enzymes Elevations). Amiodarone HCl injection concentrations greater than 3 mg/mL in D5W 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, amiodarone HCl injection concentrations should not exceed 2 mg/mL unless a central venous catheter is used (See ADVERSE REACTIONS Postmarketing Reports). Amiodarone HCl injection infusions exceeding 2 hours must be administered in glass or polyolefin bottles containing D5W. Use of evacuated glass containers for admixing amiodarone HCl injection is not recommended as incompatibility with a buffer in the container may cause precipitation. It is well known that amiodarone adsorbs to polyvinyl chloride (PVC) tubing and the clinical trial dose administration schedule was designed to account for this adsorption. All of the clinical trials were conducted using PVC tubing and its use is therefore recommended. The concentrations and rates of infusion provided in DOSAGE AND ADMINISTRATION reflect doses identified in these studies. It is important that the recommended infusion regimen be followed closely. Intravenous 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 intravenous amiodarone at higher concentrations and lower flow rates than provided in dosage and Administration. Intravenous amiodarone does not need to be protected from light during administration. AMIODARONE HCl SOLUTION STABILITY
Solution Concentration
(mg/mL) Container Comments 5% Dextrose in Water (D5W) 1.0 - 6.0 PVC Physically compatible, with amiodarone loss < 10% at 2 hours at room temperature. 5% Dextrose in Water (D5W) 1.0 - 6.0 Polyolefin, Glass Physically compatible, with no amiodarone loss at 24 hours at room temperature. Admixture Incompatibility Amiodarone HCI injection in D5W is incompatible with the drugs shown below. Y-SITE INJECTION INCOMPATIBILITY
Drug Vehicle Amiodarone Concentration Comments Aminophylline D5W 4 mg/mL Precipitate Cefamandole Nafate D5W 4 mg/mL Precipitate Cefazolin Sodium D5W 4 mg/mL Precipitate Mezlocillin Sodium D5W 4 mg/mL Precipitate Heparin Sodium D5W -- Precipitate Sodium Bicarbonate D5W 3 mg/mL Precipitate Intravenous to Oral Transition Patients whose arrhythmias have been suppressed by intravenous amiodarone may be switched to oral amiodarone. The optimal dose for changing from intravenous to oral administration of amiodarone will depend on the dose of intravenous amiodarone already administered, as well as the bioavailability of oral amiodarone. When changing to oral amiodarone therapy, clinical monitoring is recommended, particularly for elderly patients. Since there are some differences between the safety and efficacy profiles of the intravenous and oral formulations, the prescriber is advised to review the package insert for oral amiodarone when switching from intravenous to oral amiodarone therapy. Since grapefruit juice is known to inhibit CYP3A4-mediated metabolism of oral amiodarone in the intestinal mucosa, resulting in increased plasma levels of amiodarone, grapefruit juice should not be taken during treatment with oral amiodarone (see PRECAUTIONS: DRUG INTERACTIONS). The following table provides suggested doses of oral amiodarone to be initiated after varying durations of intravenous amiodarone administration. These recommendations are made on the basis of a comparable total body amount of amiodarone delivered by the intravenous and oral routes, based on 50% bioavailability of oral amiodarone. RECOMMENDATIONS FOR ORAL DOSAGE AFTER I.V. INFUSION
Duration of Amiodarone injection Infusion# Initial Daily Dose of Oral Amiodarone < 1 week 800-1600 mg 1-3 weeks 600-800 mg > 3 weeks* 400 mg # Assuming a 720 mg/day infusion (0.5 mg/min).
* Amiodarone Injection is not intended for maintenance treatment.

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Amiodarone is metabolized to desethylamiodarone by the cytochrome P450 (CYP450) enzyme group, specifically cytochrome P450 3A4 (CYP3A4) and CYP2C8. The CYP3A4 isoenzyme is present in both the liver and intestines (see CLINICAL PHARMACOLOGY, Pharmacokinetics and Metabolism). Amiodarone is also known to be an inhibitor of CYP3A4. Therefore, amiodarone has the potential for interactions with drugs or substances that may be substrates, inhibitors or inducers of CYP3A4. 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, their dose should be reassessed and, where appropriate, plasma concentration measured. 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 CYP3A4 and CYP2C8, drugs/substances that inhibit these isoenzymes may decrease the metabolism and increase serum concentration of amiodarone. Reported examples included the following: Protease Inhibitors Protease inhibitors are known to inhibit CYP3A4 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. Monitoring for amiodarone toxicity and serial measurement of amiodarone serum concentration during concomitant protease inhibitor therapy should be considered. Histamine H2 antagonists Cimetidine inhibits CYP3A4 and can increase serum amiodarone levels. Other substances Grapefruit juice given to healthy volunteers increased amiodarone AUC by 50% and Cmax by 84%, resulting in increased plasma levels of amiodarone. Grapefruit juice should not be taken during treatment with oral amiodarone. This information should be considered when changing from intravenous amiodarone to oral amiodarone (see DOSAGE AND ADMINISTRATION, Intravenous to Oral Transition). Amiodarone may suppress certain CYP450 enzymes, including CYP1A2, CYP2C9, CYP2D6, and CYP3A4. This inhibition can result in unexpectedly high plasma levels of other drugs which are metabolized by those CYP450 enzymes. Reported examples of this interaction include the following: Immunosuppressives Cyclosporine (CYP3A4 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 (CYP3A4 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, the need for digitalis therapy should be reviewed and the dose reduced by approximately 50% or discontinued. If digitalis treatment is continued, serum levels should be closely monitored and patients observed for clinical evidence of toxicity. These precautions probably should apply to digitoxin administration as well. 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. Quinidine and procainamide doses should be reduced by one-third when either is administered with amiodarone. Plasma levels of flecainide have been reported to increase in the presence of oral amiodarone; because of this, the dosage of flecainide should be adjusted when these drugs are administered concomitantly. In general, any added antiarrhythmic drug should be initiated at a lower than usual dose with careful monitoring. Combination of amiodarone with other antiarrhythmic therapy should be reserved for patients with life-threatening ventricular arrhythmias who are incompletely responsive to a single agent or incompletely responsive to amiodarone. During transfer to oral amiodarone, the dose levels of previously administered agents should be reduced by 30 to 50% several days after the addition of oral amiodarone (see DOSAGE AND ADMINISTRATION, Intravenous to Oral Transition). The continued need for the other antiarrhythmic agent should be reviewed after the effects of amiodarone have been established, and discontinuation ordinarily should be attempted. If the treatment is continued, these patients should be particularly carefully monitored for adverse effects, especially conduction disturbances and exacerbation of tachyarrhythmias, as amiodarone is continued. 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 Amiodarone should be used with caution in patients receiving β-receptor blocking agents (e.g., propranolol, a CYP3A4 inhibitor) or calcium channel antagonists (e.g., verapamil, a CYP3A4 substrate, and diltiazem, a CYP3A4 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 CYP3A4 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, the dose of the anticoagulant should be reduced by one-third to one-half, and prothrombin times should be monitored closely. Some drugs/substances are known to accelerate the metabolism of amiodarone by stimulating the synthesis of CYP3A4 (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 CYP3A4. 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 CYP3A4. Since amiodarone is a substrate for CYP3A4, there is the potential that the use of St. John's Wort in patients receiving amiodarone could result in reduced amiodarone levels. Other reported interactions with amiodarone Fentanyl (CYP3A4 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 (CYP3A4 substrate) given for local anesthesia. Seizure, associated with increased lidocaine concentrations, has been reported with concomitant administration of intravenous amiodarone. Dextromethorphanis a substrate for both CYP2D6 and CYP3A4. Amiodarone inhibits CYP2D6. Cholestyramine increases enterohepatic elimination of amiodarone and may reduce its serum levels and t½. Disopyramide increases QT prolongation which could cause 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 PRECAUTIONS, Proarrhythmia). Hemodynamic and electrophysiologic interactions have also been observed after concomitant administration with propranolol, diltiazem, and verapamil. Volatile Anesthetic Agents: (see PRECAUTIONS, Surgery). Electrolyte Disturbances Patients with hypokalemia or hypomagnesemia should have the condition corrected whenever possible before being treated with intravenous amiodarone, as these disorders can exaggerate the degree of QTc prolongation and increase the potential for torsades de pointes (TdP). Special attention should be given to electrolyte and acid-base balance in patients experiencing severe or prolonged diarrhea or in patients receiving concomitant diuretics. Last reviewed on RxList: 11/18/2008
This monograph has been modified to include the generic and brand name in many instances.

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Amiodarone HCl injection is indicated for initiation of treatment and prophylaxis of frequently recurring ventricular fibrillation and hemodynamically unstable ventricular tachycardia in patients refractory to other therapy. Intravenous 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 intravenous amiodarone, patients may be transferred to oral amiodarone therapy (see DOSAGE AND ADMINISTRATION). Intravenous amiodarone should be used for acute treatment until the patient's ventricular arrhythmias are stabilized. Most patients will require this therapy for 48 to 96 hours, but intravenous amiodarone may be safely administered for longer periods if necessary.

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Amiodarone injection is contraindicated in patients with known hypersensitivity to any of the components of amiodarone injection, including iodine, or in patients with cardiogenic shock, marked sinus bradycardia, and second- or third-degree AV block unless a functioning pacemaker is available. Last reviewed on RxList: 11/18/2008
This monograph has been modified to include the generic and brand name in many instances.

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There have been cases, some fatal, of amiodarone overdose. Effects of an inadvertent overdose of intravenous amiodarone include hypotension, cardiogenic shock, bradycardia, AV block, and hepatotoxicity. Hypotension and cardiogenic shock should be treated by slowing the infusion rate or with standard therapy: vasopressor drugs, positive inotropic agents, and volume expansion. Bradycardia and AV block may require temporary pacing. Hepatic enzyme concentrations should be monitored closely. Amiodarone is not dialyzable.

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Amiodarone Hydrochloride Injection, is supplied as: NDC Syringe Packaging Factor 25021-302-73 Amiodarone Hydrochloride Injection 150 mg/3 mL (50 mg/mL) in 3 mL Single Use Syringe 10 Single Use Syringes per Carton Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature]. Protect from light. Avoid excessive heat. Do not freeze. Use carton to protect contents from light until used. LATEX-FREE Mfg. for SAGENT Pharmaceuticals, Schaumburg, IL 60195 (USA). Mfg. by Gland Pharma, India. April 2008. FDA revision date: 2/4/2004 Last reviewed on RxList: 11/18/2008
This monograph has been modified to include the generic and brand name in many instances.

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Amiodarone injection 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. Liver Enzyme Elevations Elevations of blood hepatic enzyme values-alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT)-are seen commonly in patients with immediately lifethreatening 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. Acute, centrolobular confluent hepatocellular necrosis leading to hepatic coma, acute renal failure, and death has been associated with the administration of intravenous amiodarone at a much higher loading dose concentration and much faster rate of infusion than recommended in DOSAGE AND ADMINISTRATION. Therefore, the initial concentration and rate of infusion should be monitored closely and should not exceed that prescribed in DOSAGE AND ADMINISTRATION (see DOSAGE AND ADMINISTRATION). In patients with life-threatening arrhythmias, the potential risk of hepatic injury should be weighed against the potential benefit of intravenous amiodarone therapy, but patients receiving intravenous amiodarone should be monitored carefully for evidence of progressive hepatic injury. Consideration should be given to reducing the rate of administration or withdrawing intravenous amiodarone in such cases. Proarrhythmia Like all antiarrhythmic agents, intravenous amiodarone may cause a worsening of existing arrhythmias or precipitate a new arrhythmia. Proarrhythmia, primarily torsades de pointes (TdP), has been associated with prolongation by intravenous amiodarone of the QTc interval to 500 ms or greater. Although QTc prolongation occurred frequently in patients receiving intravenous amiodarone, torsades de pointes or new-onset VF occurred infrequently (less than 2%). Patients should be monitored for QTc prolongation during infusion with intravenous amiodarone. Combination of amiodarone with other antiarrhythmic therapy that prolongs the QTc should be reserved for patients with life-threatening ventricular arrhythmias who are incompletely responsive to a single agent. 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 DRUG INTERACTIONS, Other reported interactions with amiodarone). The need to coadminister amiodarone with any other drug known to prolong the QTc interval must be based on a careful assessment of the potential risks and benefits of doing so for each patient. A careful assessment of the potential risks and benefits of administering intravenous amiodarone must be made in patients with thyroid dysfunction due to the possibility of arrhythmia breakthrough or exacerbation of arrhythmia, which may result in death, in these patients. Pulmonary Disorders Early-onset pulmonary toxicity There have been postmarketing reports of acute-onset (days to weeks) pulmonary injury in patients treated with intravenous amiodarone. Findings have included pulmonary infiltrates on X-ray, bronchospasm, wheezing, fever, dyspnea, cough, hemoptysis, and hypoxia. Some cases have progressed to respiratory failure and/or death. ARDS Two percent (2%) of patients were reported to have adult respiratory distress syndrome (ARDS) during clinical studies involving 48 hours of therapy. ARDS is a disorder characterized by bilateral, diffuse pulmonary infiltrates with pulmonary edema and varying degrees of respiratory insufficiency. The clinical and radiographic picture can arise after a variety of lung injuries, such as those resulting from trauma, shock, prolonged cardiopulmonary resuscitation, and aspiration pneumonia, conditions present in many of the patients enrolled in the clinical studies. There have been postmarketing reports of ARDS in intravenous amiodarone patients. Intravenous amiodarone may play a role in causing or exacerbating pulmonary disorders in those patients. Postoperatively, occurrences of ARDS have been reported in patients receiving oralamiodarone therapy who have undergone either cardiac or noncardiac surgery. Although patients usually respond well to vigorous respiratory therapy, in rare instances the outcome has been fatal. Until further studies have been performed, it is recommended that FiO2 and the determinants of oxygen delivery to the tissues (e.g., SaO2, PaO2) be closely monitored in patients on amiodarone. Pulmonary fibrosis Only 1 of more than 1000 patients treated with intravenous amiodarone in clinical studies developed pulmonary fibrosis. In that patient, the condition was diagnosed 3 months after treatment with intravenous amiodarone, during which time she received oral amiodarone. Pulmonary toxicity is a well-recognized complication of long-term amiodarone use (see labeling for oral amiodarone). Surgery Close perioperative monitoring is recommended in patients undergoing general anesthesia who are on amiodarone therapy as they may be more sensitive to the myocardial depressant and conduction defects of halogenated inhalational anesthetics. Carcinogenesis, Mutagenesis, Impairment of Fertility No carcinogenicity studies were conducted with intravenous amiodarone. However, oral amiodarone caused a statistically significant, dose-related increase in the incidence of thyroid tumors (follicular adenoma and/or carcinoma) in rats. The incidence of thyroid tumors in rats was greater than the incidence in controls even at the lowest dose level tested i.e., 5 mg/kg/day (approximately 0.08 times the maximum recommended human maintenance dose*). Mutagenicity studies conducted with amiodarone HCl (Ames, micronucleus, and lysogenic induction tests) were negative. No fertility studies were conducted with intravenous amiodarone. However, in a study in which amiodarone HCl was orally administered to male and female rats, beginning 9 weeks prior to mating, reduced fertility was observed at a dose level of 90 mg/kg/day (approximately 1.4 times the maximum recommended human maintenance dose*). Pregnancy Category D. See WARNINGS, Neonatal Hypo- or Hyperthyroidism. In addition to causing infrequent congenital goiter/hypothyroidism and hyperthyroidism, amiodarone has caused a variety of adverse effects in animals. In a reproductive study in which amiodarone was given intravenously to rabbits at dosages of 5, 10, or 25 mg/kg per day (about 0.1, 0.3, and 0.7 times the maximum recommended human dose [MRHD] on a body surface area basis), maternal deaths occurred in all groups, including controls. Embryotoxicity (as manifested by fewer full-term fetuses and increased resorptions with concomitantly lower litter weights) occurred at dosages of 10 mg/kg and above. No evidence of embryotoxicity was observed at 5 mg/kg and no teratogenicity was observed at any dosages. In a teratology study in which amiodarone was administered by continuous i.v. infusion to rats at dosages of 25, 50, or 100 mg/kg per day (about 0.4, 0.7, and 1.4 times the MRHD when compared on a body surface area basis), maternal toxicity (as evidenced by reduced weight gain and food consumption) and embryotoxicity (as evidenced by increased resorptions, decreased live litter size, reduced body weights, and retarded sternum and metacarpal ossification) were observed in the 100 mg/kg group. Intravenous amiodarone should be used during pregnancy only if the potential benefit to the mother justifies the risk to the fetus. 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 should be weighed against the potential benefit of arrhythmia suppression in the mother. The mother should be advised to discontinue nursing. Labor and Delivery It is not known whether the use of amiodarone during labor or delivery has any immediate or delayed adverse effects. Preclinical studies in rodents have not shown any effect on the duration of gestation or on parturition. Pediatric Use The safety and efficacy of amiodarone in the pediatric population have not been established; therefore, its use in pediatric patients is not recommended. In a pediatric trial of 61 patients, aged 30 days to 15 years, hypotension (36%), bradycardia (20%), and atrio-ventricular block (15%) were common dose-related adverse events and were severe or life-threatening in some cases. Injection site reactions were seen in 5 (25%) of the 20 patients receiving amiodarone HCI injection through a peripheral vein irrespective of dose regimen. Amiodarone HCl injection contains the preservative benzyl alcohol (see DESCRIPTION). There have been reports of fatal “gasping syndrome” in neonates (children less than one month of age) following the administration of intravenous solutions containing the preservative benzyl alcohol. Symptoms include a striking onset of gasping respiration, hypotension, bradycardia, and cardiovascular collapse. Geriatric Use Clinical studies of intravenous amiodarone did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. *600 mg in a 50 kg patient (dose compared on a body surface area basis) Last reviewed on RxList: 11/18/2008
This monograph has been modified to include the generic and brand name in many instances.

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