Pacerone

6 ADVERSE REACTIONS The following serious adverse reactions are described in more detail in other sections of the prescribing information: Pulmonary Toxicity [see Warnings and Precautions (5.2) ] Hepatic Injury [see Warnings and Precautions (5.3) ] Worsened Arrhythmia [see Warnings and Precautions (5.4) ] Visual Impairment and Loss of Vision [see Warnings and Precautions (5.5) ] Thyroid Abnormalities [see Warnings and Precautions (5.6) ] Bradycardia [see Warnings and Precautions (5.7) ] Peripheral Neuropathy [see Warnings and Precautions (5.10) ] Photosensitivity and Skin Discoloration [see Warnings and Precautions (5.11) ] The most common reactions (>1%) leading to discontinuation of amiodarone include pulmonary toxicity, paroxysmal ventricular tachycardia, congestive heart failure, and elevation of liver enzymes. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Upsher-Smith Laboratories, LLC at 1-855-899-9180 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. At the usual maintenance dose (400 mg/day) and above, amiodarone hydrochloride causes adverse reactions in about three-fourths of all patients, resulting in discontinuation in 7% to 18%. In surveys of almost 5,000 patients treated in open U.S. studies and in published reports of treatment with amiodarone hydrochloride, the adverse reactions most frequently requiring discontinuation of amiodarone hydrochloride included pulmonary infiltrates or fibrosis, paroxysmal ventricular tachycardia, congestive heart failure, and elevation of liver enzymes. Other symptoms causing discontinuations less often included visual disturbances, photosensitivity, blue skin discoloration, hyperthyroidism, and hypothyroidism. The following side-effect rates are based on a retrospective study of 241 patients treated for 2 to 1,515 days (mean 441.3 days): Thyroid Common: Hypothyroidism, hyperthyroidism. Cardiovascular Common: Congestive heart failure, cardiac arrhythmias, SA node dysfunction. Gastrointestinal Very common: Nausea, vomiting. Common: Constipation, anorexia, abdominal pain. Dermatologic Common: Solar dermatitis/photosensitivity. Neurologic Common: Malaise and fatigue, tremor/abnormal involuntary movements, lack of coordination, abnormal gait/ataxia, dizziness, paresthesias, decreased libido, insomnia, headache, sleep disturbances. Ophthalmic Common: Visual disturbances. Hepatic Common: Abnormal liver-function tests, nonspecific hepatic disorders. Respiratory Common: Pulmonary inflammation or fibrosis. Other Common: Flushing, abnormal taste and smell, edema, abnormal salivation, coagulation abnormalities. Uncommon: Blue skin discoloration, rash, spontaneous ecchymosis, alopecia, hypotension, and cardiac conduction abnormalities. 6.2 Post-marketing Experience The following adverse reactions have been identified during post-approval use of amiodarone hydrochloride. 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. Hematologic: hemolytic anemia, aplastic anemia, pancytopenia, neutropenia, thrombocytopenia, agranulocytosis, granuloma. Immune: anaphylactic/anaphylactoid reaction (including shock), angioedema. Neurologic: pseudotumor cerebri, parkinsonian symptoms such as akinesia and bradykinesia (sometimes reversible with discontinuation of therapy), demyelinating polyneuropathy. Psychiatric: hallucination, confusional state, disorientation, delirium. Cardiac: hypotension (sometimes fatal), sinus arrest. Respiratory: eosinophilic pneumonia, acute respiratory distress syndrome in the post-operative setting, bronchospasm, bronchiolitis obliterans organizing pneumonia, pulmonary alveolar hemorrhage, pleural effusion, pleuritis. Gastrointestinal: pancreatitis, acute pancreatitis. Hepatic: hepatitis, cholestatic hepatitis, cirrhosis. Skin and Subcutaneous Tissue Disorders: urticaria, toxic epidermal necrolysis (sometimes fatal), erythema multiforme, Stevens-Johnson syndrome, exfoliative dermatitis, bullous dermatitis, drug rash with eosinophilia and systemic symptoms (DRESS), eczema, pruritus, skin cancer, lupus-like syndrome. Musculoskeletal: myopathy, muscle weakness, rhabdomyolysis. Renal: renal impairment, renal insufficiency, acute renal failure. Reproductive: epididymitis, impotence. Body as a whole: fever, dry mouth. Endocrine and metabolic: thyroid nodules/ thyroid cancer, syndrome of inappropriate antidiuretic hormone secretion (SIADH). Vascular: vasculitis.

4 CONTRAINDICATIONS Cardiogenic shock. Sick sinus syndrome, second- or third-degree atrioventricular block, bradycardia leading to syncope without a functioning pacemaker. Known hypersensitivity to the drug or to any of its components, including iodine. Pacerone is contraindicated in patients with ( 4 ): Cardiogenic shock. Sick sinus syndrome, second- or third-degree AV block, bradycardia leading to syncope without a functioning pacemaker. Known hypersensitivity to the drug or any of its components.

11 DESCRIPTION Pacerone (amiodarone hydrochloride tablets, USP) are an antiarrhythmic drug, available for oral administration as 100 mg; peach tablets, 200 mg; pink tablets and 400 mg; white tablets containing amiodarone hydrochloride, USP. All three strengths of Pacerone tablets contain the following inactive ingredients: lactose monohydrate, magnesium stearate, povidone, pregelatinized corn starch, sodium starch glycolate and stearic acid. The 200 mg tablets also contain FD&C Red No. 40 and FD&C Yellow No. 6. The 100 mg tablets also contain FD&C Yellow No. 6. Amiodarone hydrochloride, USP is a benzofuran derivative: 2-butyl-3-benzofuranyl 4-[2-(diethylamino)-ethoxy]-3,5-diiodophenyl ketone hydrochloride. The structural formula is as follows: C 25 H 29 I 2 NO 3 ∙ HCl Molecular Weight: 681.8 C 25 H 29 I 2 NO 3 ∙ HCl Molecular Weight: 681.8 Amiodarone hydrochloride, USP is a white to cream-colored crystalline powder. It is slightly soluble in water, soluble in alcohol, and freely soluble in chloroform. It contains 37.3% iodine by weight. Meets USP Dissolution Test 4. Chemical Structure

2 DOSAGE AND ADMINISTRATION Dosage must be individualized based on severity of arrhythmia and response. Use the lowest effective dose. Obtain baseline chest x-ray, pulmonary function tests, thyroid function tests, and liver aminotransferases. Correct hypokalemia, hypomagnesemia, and hypocalcemia before initiating treatment. Initiate treatment with a loading dose of 800 to 1600 mg/day until initial therapeutic response occurs (usually 1 to 3 weeks). Once adequate arrhythmia control is achieved, or if side effects become prominent, reduce Pacerone tablets dose to 600 to 800 mg/day for one month and then to the maintenance dose, usually 400 mg/day. ( 2 ) Recommended Dosage: Initiate treatment with a loading dose of 800 to 1600 mg/day until initial therapeutic response occurs (usually 1 to 3 weeks). Once adequate arrhythmia control is achieved, or if side effects become prominent, reduce Pacerone tablet dose to 600 to 800 mg/day for one month and then to the maintenance dose, usually 400 mg/day. Administration: Administer Pacerone tablets consistently with regard to meals [see Clinical Pharmacology (12.3) ] . Administration of Pacerone tablets in divided doses with meals is suggested for total daily doses of 1000 mg or higher, or when gastrointestinal intolerance occurs.

1 INDICATIONS AND USAGE Pacerone is indicated for the treatment of documented, life-threatening recurrent ventricular fibrillation and life-threatening recurrent hemodynamically unstable tachycardia in adults who have not responded to adequate doses of other available antiarrhythmics or when alternative agents cannot be tolerated. Pacerone is an antiarrhythmic indicated for: Recurrent ventricular fibrillation. ( 1 ) Recurrent hemodynamically unstable ventricular tachycardia. ( 1 )

10 OVERDOSAGE There have been cases, some fatal, of amiodarone hydrochloride overdose. Monitor the patient's cardiac rhythm and blood pressure, and, if bradycardia ensues, a β-adrenergic agonist or a pacemaker may be used. Treat hypotension with inadequate tissue perfusion with positive inotropic and vasopressor agents. Neither Pacerone nor its metabolite is dialyzable.

7 DRUG INTERACTIONS Because of amiodarone's long half-life, expect drug interactions to persist for weeks to months after discontinuation of amiodarone. Drug interactions with amiodarone are described in Table 1 below. Table 1: Amiodarone Drug Interactions Concomitant Drug Class/Name Examples Clinical Comment Pharmacodynamic Interactions QT Prolonging Drugs class I and III antiarrhythmics, lithium, certain phenothiazines, tricyclic antidepressants, certain fluoroquinolone and macrolide antibiotics, azole antifungals, halogenated inhalation anesthetic agents Increased risk of Torsade de Pointes. Avoid concomitant use. Negative Chronotropes digoxin, beta blockers, verapamil, diltiazem, clonidine, ivabradine Potentiates the electrophysiologic and hemodynamic effects of amiodarone, resulting in bradycardia, sinus arrest, and AV block. Monitor heart rate. Pharmacokinetic Interactions CYP450 Inhibitors grapefruit juice, certain fluoroquinolone and macrolide antibiotics, azole antifungals, cimetidine, certain protease inhibitors Increased exposure of amiodarone. Avoid concomitant use. CYP450 Inducers St. John's Wort Reduced amiodarone serum levels. Cyclosporine Increased plasma levels of cyclosporine have been reported resulting in elevated creatinine, despite reduction of cyclosporine dose. Monitor cyclosporine drug levels and renal function with concomitant use. Cholestyramine Reduced amiodarone serum levels. Antiarrhythmics quinidine, procainamide, flecainide Reserve concomitant use for patients who are unresponsive to a single agent. Antiarrhythmic metabolism inhibited by amiodarone. Initiate antiarrhythmic at a lower than usual dose and monitor patient carefully. Reduce dose levels of previously administered antiarrhythmic by 30% to 50% for several days after transitioning to oral amiodarone. Evaluate continued need for antiarrhythmic. Digoxin Increased digoxin concentration. Reduce digoxin by half or discontinue. If continued, monitor for evidence of toxicity. HMG-CoA Reductase Inhibitors simvastatin, lovastatin, atorvastatin Increased plasma concentration of HMG-CoA reductase inhibitor. Limit the dose of lovastatin to 40 mg. Limit the coadministered dose of simvastatin to 20 mg. Lower starting dose of other CYP3A4 substrates may be required. Warfarin Potentiates anticoagulant response and can result in serious or fatal bleeding. Coadministration increases prothrombin time by 100% after 3 to 4 days. Reduce warfarin dose by one-third to one-half and monitor prothrombin times. Phenytoin Increased steady-state levels of phenytoin. Monitor phenytoin levels. Hepatitis C Direct Acting Antiviral sofosbuvir Cases of symptomatic bradyarrhythmia requiring pacemaker insertion have been reported in patients on oral maintenance amiodarone who initiated therapy with sofosbuvir. CYP3A Substrate lidocaine Sinus bradycardia has been reported with oral amiodarone in combination with lidocaine given for local anesthesia. Monitor heart rate. A lower starting dose of lidocaine may be required. CYP3A Substrate fentanyl Fentanyl in combination with amiodarone may cause hypotension, bradycardia, and decreased cardiac output. Avoid coadministration of amiodarone with other antiarrhythmics and drugs known to prolong the QT interval. ( 7 ) 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 )

12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Amiodarone is considered a class III antiarrhythmic drug, but it possesses electrophysiologic characteristics of all four Vaughan Williams classes. Like class I drugs, amiodarone blocks sodium channels at rapid pacing frequencies, and like class II drugs, amiodarone exerts a noncompetitive antisympathetic action. One of its main effects, with prolonged administration, is to lengthen the cardiac action potential, a class III effect. The negative chronotropic effect of amiodarone in nodal tissues is similar to the effect of class IV drugs. In addition to blocking sodium channels, amiodarone blocks myocardial potassium channels, which contributes to slowing of conduction and prolongation of refractoriness. The antisympathetic action and the block of calcium and potassium channels are responsible for the negative dromotropic effects on the sinus node and for the slowing of conduction and prolongation of refractoriness in the atrioventricular (AV) node. Its vasodilatory action can decrease cardiac workload and consequently myocardial oxygen consumption. Pacerone prolongs the duration of the action potential of all cardiac fibers while causing minimal reduction of dV/dt (maximal upstroke velocity of the action potential). The refractory period is prolonged in all cardiac tissues. Amiodarone hydrochloride increases the cardiac refractory period without influencing resting membrane potential, except in automatic cells where the slope of the prepotential is reduced, generally reducing automaticity. These electrophysiologic effects are reflected in a decreased sinus rate of 15% to 20%, increased PR and QT intervals of about 10%, the development of U-waves, and changes in T-wave contour. These changes should not require discontinuation of Pacerone as they are evidence of its pharmacological action, although Pacerone can cause marked sinus bradycardia or sinus arrest and heart block [see Warnings and Precautions (5.4) ] . Hemodynamics In animal studies and after intravenous administration in man, amiodarone hydrochloride relaxes vascular smooth muscle, reduces peripheral vascular resistance (afterload), and slightly increases cardiac index. After oral dosing, however, amiodarone hydrochloride produces no significant change in left ventricular ejection fraction (LVEF), even in patients with depressed LVEF. After acute intravenous dosing in man, amiodarone hydrochloride may have a mild negative inotropic effect. 12.2 Pharmacodynamics There is no well-established relationship between plasma concentration and effectiveness, but it does appear that concentrations much below 1 mg/L are often ineffective and that levels above 2.5 mg/L are generally not needed. Plasma-concentration measurements can be used to identify patients whose levels are unusually low, and who might benefit from a dose increase, or unusually high, and who might have dosage reduction in the hope of minimizing side effects. Effects on abnormal rhythms are not seen before 2 to 3 days and usually require 1 to 3 weeks, even when a loading dose is used. There may be a continued increase in effect for longer periods still. There is evidence that the time to effect is shorter when a loading-dose regimen is used. Consistent with the slow rate of elimination, antiarrhythmic effects persist for weeks or months after amiodarone hydrochloride is discontinued, but the time of recurrence is variable and unpredictable. In general, when the drug is resumed after recurrence of the arrhythmia, control is established relatively rapidly compared to the initial response, presumably because tissue stores were not wholly depleted. 12.3 Pharmacokinetics Absorption Following oral administration in humans, amiodarone hydrochloride is slowly and variably absorbed. The bioavailability of amiodarone hydrochloride is approximately 50%. Maximum plasma concentrations are attained 3 to 7 hours after a single dose. Plasma concentrations with chronic dosing at 100 to 600 mg/day are approximately dose proportional, with a mean 0.5 mg/L increase for each 100 mg/day. These means, however, include considerable individual variability. Food increases the rate and extent of absorption of amiodarone hydrochloride. The effects of food upon the bioavailability of amiodarone hydrochloride have been studied in 30 healthy subjects who received a single 600-mg dose immediately after consuming a high-fat meal and following an overnight fast. The area under the plasma concentration-time curve (AUC) and the peak plasma concentration (C max ) of amiodarone increased by 2.3 (range 1.7 to 3.6) and 3.8 (range 2.7 to 4.4) times, respectively, in the presence of food. Food also increased the rate of absorption of amiodarone, decreasing the time to peak plasma concentration (T max ) by 37%. The mean AUC and mean C max of the major metabolite of amiodarone, DEA increased by 55% (range 58% to 101%) and 32% (range 4% to 84%), respectively, but there was no change in the T max in the presence of food. Distribution Pacerone is highly protein-bound (approximately 96%). Pacerone has a very large but variable volume of distribution, averaging about 60 L/kg, because of extensive accumulation in various sites, especially adipose tissue and highly perfused organs, such as the liver, lung, and spleen. One major metabolite of amiodarone hydrochloride, DEA, has been identified in man; it accumulates to an even greater extent in almost all tissues. No data are available on the activity of DEA in humans, but in animals, it has significant electrophysiologic and antiarrhythmic effects generally similar to amiodarone itself. DEA's precise role and contribution to the antiarrhythmic activity of oral amiodarone are not certain. The development of maximal ventricular class III effects after oral amiodarone hydrochloride administration in humans correlates more closely with DEA accumulation over time than with amiodarone accumulation. Elimination Following single dose administration in 12 healthy subjects, amiodarone hydrochloride exhibited multi-compartmental pharmacokinetics with a mean apparent plasma terminal elimination half-life of 58 days (range 15 to 142 days) for amiodarone and 36 days (range 14 to 75 days) for the active metabolite (DEA). In patients, following discontinuation of chronic oral therapy, amiodarone hydrochloride has been shown to have a biphasic elimination with an initial 50% reduction of plasma levels after 2.5 to 10 days. A much slower terminal plasma-elimination phase shows a half-life of the parent compound ranging from 26 to 107 days, with a mean of approximately 53 days and most patients in the 40- to 55-day range. In the absence of a loading-dose period, steady-state plasma concentrations, at constant oral dosing, would therefore be reached between 130 and 535 days, with an average of 265 days. For the metabolite, the mean plasma-elimination half-life was approximately 61 days. These data probably reflect an initial elimination of drug from well-perfused tissue (the 2.5- to 10-day half-life phase), followed by a terminal phase representing extremely slow elimination from poorly perfused tissue compartments such as fat. The considerable inter-subject variation in both phases of elimination, as well as uncertainty as to what compartment is critical to drug effect, requires attention to individual responses once arrhythmia control is achieved with loading doses because the correct maintenance dose is determined, in part, by the elimination rates. Individualize maintenance doses of Pacerone tablets [see Dosage and Administration (2) ] . Metabolism Amiodarone is metabolized to DEA by the cytochrome P450 (CYP) enzyme group, specifically CYP3A and CYP2C8. The CYP3A isoenzyme is present in both the liver and intestines. In vitro , amiodarone and DEA exhibit a potential to inhibit CYP2C9, CYP2C19, CYP2D6, CYP3A, CYP2A6, CYP2B6 and CYP2C8. Amiodarone and DEA have also a potential to inhibit some transporters such as P-glycoprotein and organic cation transporter (OCT2). Excretion Amiodarone is eliminated primarily by hepatic metabolism and biliary excretion and there is negligible excretion of amiodarone or DEA in urine. Neither amiodarone nor DEA is dialyzable. Specific Populations Effect of Age: Normal subjects over 65 years of age show lower clearances (about 100 mL/hr/kg) than younger subjects (about 150 mL/hr/kg) and an increase in t½ from about 20 to 47 days. Renal Impairment: Renal impairment does not influence the pharmacokinetics of amiodarone or DEA. Hepatic Impairment: After a single dose of intravenous amiodarone to cirrhotic patients, significantly lower C max and average concentration values are seen for DEA, but mean amiodarone levels are unchanged. Cardiac Disease: In patients with severe left ventricular dysfunction, the pharmacokinetics of amiodarone are not significantly altered but the terminal elimination t½ of DEA is prolonged. Although no dosage adjustment for patients with renal, hepatic, or cardiac abnormalities has been defined during chronic treatment with oral amiodarone, close clinical monitoring is prudent for elderly patients and those with severe left ventricular dysfunction. Drug Interactions: Effects of other agents on amiodarone Grapefruit juice: Grapefruit juice given to healthy volunteers increased amiodarone AUC by 50% and C max by 84%, and decreased DEA to unquantifiable concentrations. Cimetidine inhibits CYP3A and can increase serum amiodarone levels. Cholestyramine reduces enterohepatic circulation of amiodarone thereby increasing its elimination. This results in reduced amiodarone serum levels and half-life. Effects of amiodarone on agents CYP3A substrates: Amiodarone taken concomitantly with quinidine increases the 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. Loratadine , a non-sedating antihistaminic, is metabolized primarily by CYP3A and its metabolism can be inhibited by amiodarone. Metabolism of lidocaine can be inhibited by amiodarone. Cyclophosphamide is a prodrug, metabolized by CYP450 including CYP3A to an active metabolite. The metabolism of cyclophosphamide may be inhibited by amiodarone. 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. Macrolide/ketolide antibiotics: Amiodarone can inhibit the metabolism of macrolide/ketolide antibiotics (except for azithromycin) and systemic azole antifungal drugs. P-glycoprotein substrates: Amiodarone taken concomitantly with digoxin increases the serum digoxin concentration by 70% after one day. Dabigatran etexilate when taken concomitantly with oral amiodarone can result in elevated serum concentration of dabigatran. Dextromethorphan is a substrate for both CYP2D6 and CYP3A. Amiodarone inhibits CYP2D6. Chronic (>2 weeks) oral amiodarone administration impairs metabolism of dextromethorphan can lead to increased serum concentrations.

12.1 Mechanism of Action Amiodarone is considered a class III antiarrhythmic drug, but it possesses electrophysiologic characteristics of all four Vaughan Williams classes. Like class I drugs, amiodarone blocks sodium channels at rapid pacing frequencies, and like class II drugs, amiodarone exerts a noncompetitive antisympathetic action. One of its main effects, with prolonged administration, is to lengthen the cardiac action potential, a class III effect. The negative chronotropic effect of amiodarone in nodal tissues is similar to the effect of class IV drugs. In addition to blocking sodium channels, amiodarone blocks myocardial potassium channels, which contributes to slowing of conduction and prolongation of refractoriness. The antisympathetic action and the block of calcium and potassium channels are responsible for the negative dromotropic effects on the sinus node and for the slowing of conduction and prolongation of refractoriness in the atrioventricular (AV) node. Its vasodilatory action can decrease cardiac workload and consequently myocardial oxygen consumption. Pacerone prolongs the duration of the action potential of all cardiac fibers while causing minimal reduction of dV/dt (maximal upstroke velocity of the action potential). The refractory period is prolonged in all cardiac tissues. Amiodarone hydrochloride increases the cardiac refractory period without influencing resting membrane potential, except in automatic cells where the slope of the prepotential is reduced, generally reducing automaticity. These electrophysiologic effects are reflected in a decreased sinus rate of 15% to 20%, increased PR and QT intervals of about 10%, the development of U-waves, and changes in T-wave contour. These changes should not require discontinuation of Pacerone as they are evidence of its pharmacological action, although Pacerone can cause marked sinus bradycardia or sinus arrest and heart block [see Warnings and Precautions (5.4) ] . Hemodynamics In animal studies and after intravenous administration in man, amiodarone hydrochloride relaxes vascular smooth muscle, reduces peripheral vascular resistance (afterload), and slightly increases cardiac index. After oral dosing, however, amiodarone hydrochloride produces no significant change in left ventricular ejection fraction (LVEF), even in patients with depressed LVEF. After acute intravenous dosing in man, amiodarone hydrochloride may have a mild negative inotropic effect.

12.2 Pharmacodynamics There is no well-established relationship between plasma concentration and effectiveness, but it does appear that concentrations much below 1 mg/L are often ineffective and that levels above 2.5 mg/L are generally not needed. Plasma-concentration measurements can be used to identify patients whose levels are unusually low, and who might benefit from a dose increase, or unusually high, and who might have dosage reduction in the hope of minimizing side effects. Effects on abnormal rhythms are not seen before 2 to 3 days and usually require 1 to 3 weeks, even when a loading dose is used. There may be a continued increase in effect for longer periods still. There is evidence that the time to effect is shorter when a loading-dose regimen is used. Consistent with the slow rate of elimination, antiarrhythmic effects persist for weeks or months after amiodarone hydrochloride is discontinued, but the time of recurrence is variable and unpredictable. In general, when the drug is resumed after recurrence of the arrhythmia, control is established relatively rapidly compared to the initial response, presumably because tissue stores were not wholly depleted.

12.3 Pharmacokinetics Absorption Following oral administration in humans, amiodarone hydrochloride is slowly and variably absorbed. The bioavailability of amiodarone hydrochloride is approximately 50%. Maximum plasma concentrations are attained 3 to 7 hours after a single dose. Plasma concentrations with chronic dosing at 100 to 600 mg/day are approximately dose proportional, with a mean 0.5 mg/L increase for each 100 mg/day. These means, however, include considerable individual variability. Food increases the rate and extent of absorption of amiodarone hydrochloride. The effects of food upon the bioavailability of amiodarone hydrochloride have been studied in 30 healthy subjects who received a single 600-mg dose immediately after consuming a high-fat meal and following an overnight fast. The area under the plasma concentration-time curve (AUC) and the peak plasma concentration (C max ) of amiodarone increased by 2.3 (range 1.7 to 3.6) and 3.8 (range 2.7 to 4.4) times, respectively, in the presence of food. Food also increased the rate of absorption of amiodarone, decreasing the time to peak plasma concentration (T max ) by 37%. The mean AUC and mean C max of the major metabolite of amiodarone, DEA increased by 55% (range 58% to 101%) and 32% (range 4% to 84%), respectively, but there was no change in the T max in the presence of food. Distribution Pacerone is highly protein-bound (approximately 96%). Pacerone has a very large but variable volume of distribution, averaging about 60 L/kg, because of extensive accumulation in various sites, especially adipose tissue and highly perfused organs, such as the liver, lung, and spleen. One major metabolite of amiodarone hydrochloride, DEA, has been identified in man; it accumulates to an even greater extent in almost all tissues. No data are available on the activity of DEA in humans, but in animals, it has significant electrophysiologic and antiarrhythmic effects generally similar to amiodarone itself. DEA's precise role and contribution to the antiarrhythmic activity of oral amiodarone are not certain. The development of maximal ventricular class III effects after oral amiodarone hydrochloride administration in humans correlates more closely with DEA accumulation over time than with amiodarone accumulation. Elimination Following single dose administration in 12 healthy subjects, amiodarone hydrochloride exhibited multi-compartmental pharmacokinetics with a mean apparent plasma terminal elimination half-life of 58 days (range 15 to 142 days) for amiodarone and 36 days (range 14 to 75 days) for the active metabolite (DEA). In patients, following discontinuation of chronic oral therapy, amiodarone hydrochloride has been shown to have a biphasic elimination with an initial 50% reduction of plasma levels after 2.5 to 10 days. A much slower terminal plasma-elimination phase shows a half-life of the parent compound ranging from 26 to 107 days, with a mean of approximately 53 days and most patients in the 40- to 55-day range. In the absence of a loading-dose period, steady-state plasma concentrations, at constant oral dosing, would therefore be reached between 130 and 535 days, with an average of 265 days. For the metabolite, the mean plasma-elimination half-life was approximately 61 days. These data probably reflect an initial elimination of drug from well-perfused tissue (the 2.5- to 10-day half-life phase), followed by a terminal phase representing extremely slow elimination from poorly perfused tissue compartments such as fat. The considerable inter-subject variation in both phases of elimination, as well as uncertainty as to what compartment is critical to drug effect, requires attention to individual responses once arrhythmia control is achieved with loading doses because the correct maintenance dose is determined, in part, by the elimination rates. Individualize maintenance doses of Pacerone tablets [see Dosage and Administration (2) ] . Metabolism Amiodarone is metabolized to DEA by the cytochrome P450 (CYP) enzyme group, specifically CYP3A and CYP2C8. The CYP3A isoenzyme is present in both the liver and intestines. In vitro , amiodarone and DEA exhibit a potential to inhibit CYP2C9, CYP2C19, CYP2D6, CYP3A, CYP2A6, CYP2B6 and CYP2C8. Amiodarone and DEA have also a potential to inhibit some transporters such as P-glycoprotein and organic cation transporter (OCT2). Excretion Amiodarone is eliminated primarily by hepatic metabolism and biliary excretion and there is negligible excretion of amiodarone or DEA in urine. Neither amiodarone nor DEA is dialyzable. Specific Populations Effect of Age: Normal subjects over 65 years of age show lower clearances (about 100 mL/hr/kg) than younger subjects (about 150 mL/hr/kg) and an increase in t½ from about 20 to 47 days. Renal Impairment: Renal impairment does not influence the pharmacokinetics of amiodarone or DEA. Hepatic Impairment: After a single dose of intravenous amiodarone to cirrhotic patients, significantly lower C max and average concentration values are seen for DEA, but mean amiodarone levels are unchanged. Cardiac Disease: In patients with severe left ventricular dysfunction, the pharmacokinetics of amiodarone are not significantly altered but the terminal elimination t½ of DEA is prolonged. Although no dosage adjustment for patients with renal, hepatic, or cardiac abnormalities has been defined during chronic treatment with oral amiodarone, close clinical monitoring is prudent for elderly patients and those with severe left ventricular dysfunction. Drug Interactions: Effects of other agents on amiodarone Grapefruit juice: Grapefruit juice given to healthy volunteers increased amiodarone AUC by 50% and C max by 84%, and decreased DEA to unquantifiable concentrations. Cimetidine inhibits CYP3A and can increase serum amiodarone levels. Cholestyramine reduces enterohepatic circulation of amiodarone thereby increasing its elimination. This results in reduced amiodarone serum levels and half-life. Effects of amiodarone on agents CYP3A substrates: Amiodarone taken concomitantly with quinidine increases the 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. Loratadine , a non-sedating antihistaminic, is metabolized primarily by CYP3A and its metabolism can be inhibited by amiodarone. Metabolism of lidocaine can be inhibited by amiodarone. Cyclophosphamide is a prodrug, metabolized by CYP450 including CYP3A to an active metabolite. The metabolism of cyclophosphamide may be inhibited by amiodarone. 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. Macrolide/ketolide antibiotics: Amiodarone can inhibit the metabolism of macrolide/ketolide antibiotics (except for azithromycin) and systemic azole antifungal drugs. P-glycoprotein substrates: Amiodarone taken concomitantly with digoxin increases the serum digoxin concentration by 70% after one day. Dabigatran etexilate when taken concomitantly with oral amiodarone can result in elevated serum concentration of dabigatran. Dextromethorphan is a substrate for both CYP2D6 and CYP3A. Amiodarone inhibits CYP2D6. Chronic (>2 weeks) oral amiodarone administration impairs metabolism of dextromethorphan can lead to increased serum concentrations.

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3 DOSAGE FORMS AND STRENGTHS Pacerone tablets, 100 mg, are peach, round, flat-faced, uncoated tablets, debossed with "P" on one side, and "U-S" above "144" on the other side. Pacerone tablets, 200 mg, are pink, round, flat-faced, scored, uncoated tablets, debossed with "P 200 " on the unscored side, and "U-S" above and "0147" below the score on the reverse side. Pacerone tablets, 400 mg, are white to off-white, round, uncoated, scored tablets, debossed with "U-S' above and "1645' below the score on one side and "P 400 " on the unscored side. Tablets: 100 mg, 200 mg and 400 mg ( 3 )

Pacerone Amiodarone Hydrochloride Amiodarone Hydrochloride Amiodarone lactose monohydrate magnesium stearate povidone, unspecified starch, corn sodium starch glycolate type A potato stearic acid FD&C Yellow No. 6 Peach P;U;S;144 Pacerone Amiodarone Hydrochloride Amiodarone Hydrochloride Amiodarone lactose monohydrate magnesium stearate povidone, unspecified starch, corn sodium starch glycolate type A potato stearic acid FD&C Yellow No. 6 FD&C Red No. 40 P200;U;S;0147 Pacerone Amiodarone Hydrochloride Amiodarone Hydrochloride Amiodarone lactose monohydrate magnesium stearate povidone, unspecified starch, corn sodium starch glycolate type A potato stearic acid off-white P400;U;S;1645

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Amiodarone hydrochloride was associated with a statistically significant, dose-related increase in the incidence of thyroid tumors (follicular adenoma and/or carcinoma) in rats. The incidence of thyroid tumors was greater than control at the lowest dose level tested, i.e., 5 mg/kg/day (approximately 0.08 times the maximum recommended human maintenance dose 600 mg in a 60 kg patient (dose compared on a body surface area basis) ). Mutagenicity studies (Ames, micronucleus, and lysogenic tests) with amiodarone hydrochloride were negative. In a study in which amiodarone hydrochloride was 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 ).

13 NONCLINICAL TOXICOLOGY 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Amiodarone hydrochloride was associated with a statistically significant, dose-related increase in the incidence of thyroid tumors (follicular adenoma and/or carcinoma) in rats. The incidence of thyroid tumors was greater than control at the lowest dose level tested, i.e., 5 mg/kg/day (approximately 0.08 times the maximum recommended human maintenance dose 600 mg in a 60 kg patient (dose compared on a body surface area basis) ). Mutagenicity studies (Ames, micronucleus, and lysogenic tests) with amiodarone hydrochloride were negative. In a study in which amiodarone hydrochloride was 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 ).

ANDA075135

Pacerone

Amiodarone Hydrochloride

0245-1645

HUMAN PRESCRIPTION DRUG

ORAL

PRINCIPAL DISPLAY PANEL - 100 mg Tablet Bottle Label NDC 0245-0144-30 Pacerone ® (Amiodarone Hydrochloride Tablets, USP) 100 mg PHARMACIST: Dispense the Medication Guide provided separately to each patient. 30 Tablets Rx only UPSHER-SMITH PRINCIPAL DISPLAY PANEL - 100 mg Tablet Bottle Label

Manufactured by UPSHER-SMITH LABORATORIES, LLC Maple Grove, MN 55369 Pacerone is a registered trademark of Upsher-Smith Laboratories, LLC. Revised: 9/2020

17 PATIENT COUNSELING INFORMATION Advise the patient to read the FDA-approved patient labeling (Medication Guide). Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to inform their prescriber of a known or suspected pregnancy [see Use in Specific Populations (8.1) ] . Advise women that breastfeeding is not recommended during treatment with Pacerone [see Use in Specific Populations (8.2) ] . Advise patients to avoid grapefruit juice and St. John's Wort. Advise patients to seek medical attention if they experience the signs and symptoms of pulmonary toxicity, worsening arrhythmia, bradycardia, visual impairment, or hypo- and hyperthyroidism. This product's label may have been updated. For full prescribing information, please visit www.upsher-smith.com.

MEDICATION GUIDE Pacerone ® (PĀS-ər-ōn) Tablets (Amiodarone Hydrochloride) What is the most important information I should know about Pacerone tablets? Pacerone tablets can cause serious side effects that can lead to death, including: lung problems liver problems worsening of heartbeat problems Call your healthcare provider or get medical help right away if you have any of the following symptoms during treatment with Pacerone tablets: trouble breathing, wheezing, shortness of breath, coughing chest pain, spitting up of blood, or fever nausea or vomiting, brown or dark-colored urine, feel more tired than usual, yellowing of your skin or the whites of your eyes (jaundice), or right upper stomach-area pain heart pounding, skipping a beat, beating fast or slowly, feel light-headed, or if you faint vision problems, including blurred vision, see halos, or your eyes become sensitive to light. You should have regular eye exams before and during treatment with Pacerone tablets. Pacerone tablets should be started in a hospital so that your medical condition can be carefully monitored. Pacerone tablets should only be used to treat people who have been diagnosed with life-threatening heartbeat problems called ventricular arrhythmias, when other treatments did not work or you cannot tolerate them. Pacerone tablets can cause other serious side effects. See " What are the possible side effects of Pacerone tablets? " If you get serious side effects during treatment you may need to stop Pacerone tablets, have your dose changed, or get medical treatment. Talk with your healthcare provider before you stop taking Pacerone tablets. You may still have side effects after stopping Pacerone tablets because the medicine stays in your body for months after treatment is stopped. You should have regular check-ups, blood tests, chest x-rays before and during treatment with Pacerone tablets to check for serious side effects. You should also have lung function tests before starting treatment with Pacerone tablets. What are Pacerone tablets? Pacerone tablets are a prescription medicine used to treat people who have been diagnosed with life-threatening heartbeat problems called ventricular arrhythmias, when other treatments did not work or you cannot tolerate them. It is not known if Pacerone tablets are safe and effective in children. Who should not take Pacerone tablets? Do not take Pacerone tablets if you: have a serious heart problem called cardiogenic shock have certain types of the heart condition called heart block, with or without a slow heart rate have a slow heart rate with dizziness or lightheadedness, and you do not have an implanted pacemaker are allergic to amiodarone, iodine, or any of the other ingredients in Pacerone tablets. See the end of this Medication Guide for a complete list of ingredients in Pacerone tablets. Before taking Pacerone tablets, tell your healthcare provider about all of your medical conditions, including if you: have lung or breathing problems have liver problems have or had thyroid problems have a slow heart rate or blood pressure problems have diarrhea or have had diarrhea for a long period of time have been told that you have low levels of potassium, magnesium, or calcium in your blood have an implanted pacemaker or defibrillator if you plan to have surgery with general anesthesia are pregnant or plan to become pregnant. Pacerone tablets may harm your unborn baby. Tell your healthcare provider right away if you become pregnant during treatment with Pacerone tablets. Pacerone can stay in your body for months after treatment is stopped. are breastfeeding or plan to breastfeed. Pacerone can pass into your breast milk and may harm your baby. You should not breast feed while taking Pacerone tablets. Pacerone can stay in your body for months after treatment is stopped. Talk to your healthcare provider about the best way to feed your baby during this time. Tell your healthcare provider about all the medicines you take including prescription and over-the-counter medicines, vitamins, and herbal supplements. Pacerone tablets and certain other medicines can affect with each other and cause serious side effects. You can ask your pharmacist for a list of medicines that interact with Pacerone tablets. How should I take Pacerone tablets? When you are discharged from the hospital, take Pacerone tablets exactly as your doctor tells you to take it. Your healthcare provider will tell you how much Pacerone to take and when to take it. Your healthcare provider may change your dose of Pacerone as needed if your heart rhythm is controlled, or if you have certain side effects. Your healthcare provider should monitor you carefully when your dose of Pacerone is being changed. Take your dose of Pacerone tablets the same way each time, either with or without food. If you take too much Pacerone, call your healthcare provider or go to the nearest hospital emergency room right away. If you miss a dose, wait and take your next dose at your regular time. Do not take two doses at the same time. Continue with your next regularly scheduled dose. What should I avoid while taking Pacerone tablets? Avoid drinking grapefruit juice during treatment with Pacerone. Drinking grapefruit juice with Pacerone tablets may increase the amount of Pacerone in your blood, and this may lead to side effects. Pacerone tablets can make your skin sensitive to sunlight. You could get severe sunburn. Use sunscreen and wear a hat and clothes that cover your skin to help protect you if you must be in sunlight. Talk to your healthcare if you get a sunburn. See " Skin problems " in the Medication Guide section "What are the possible side effects of Pacerone tablets?" below. What are the possible side effects of Pacerone tablets? Pacerone tablets can cause serious side effects, including: See " What is the most important information I should know about Pacerone tablets? " Nerve problems . Pacerone tablets can cause nerve problems. Call your healthcare provider if you develop symptoms of nerve problems, including: a feeling of "pins and needles" or numbness in your hands, legs, or feet, muscle weakness, uncontrolled movements, poor coordination, or trouble walking. Skin problems . Pacerone tablets can cause your skin to be more sensitive to the sun or turn a bluish-gray color. People who have fair skin or people who have a lot of sun exposure may be more at risk for these skin problems. Some of the bluish-gray skin color may return to normal after stopping Pacerone tablets. Thyroid problems. Pacerone tablets can cause you to have either decreased thyroid function (hypothyroidism), which can sometimes be severe, or an overactive thyroid (hyperthyroidism), which can be severe. If you develop decreased thyroid function during treatment with Pacerone tablets, your healthcare provider may need to reduce your dose or stop your treatment with Pacerone tablets, and possibly prescribe medicine to replace your thyroid hormone. An overactive thyroid can cause you to produce too much thyroid hormone. You can have abnormal heartbeats even while you are receiving Pacerone tablets. Your healthcare provider may prescribe certain medicines to treat your overactive thyroid. Call your healthcare provider if you get any abnormal heartbeats during treatment with Pacerone tablets. This may mean that you have an overactive thyroid. Your healthcare provider should do tests to check your thyroid function before you start and during treatment with Pacerone tablets. Call your healthcare provider if you develop any of the following symptoms of a thyroid problem during treatment with Pacerone tablets: weakness weight loss or weight gain heat or cold intolerance hair thinning sweating changes in your menstrual periods swelling of your neck (goiter) nervousness irritability restlessness decreased concentration feeling depressed (in the elderly) tremor The most common side effects of Pacerone tablets include: lung problems heartbeat problems heart problems liver problems Pacerone tablets may affect fertility in males and females. It is not known if the effects are reversible. Talk to your healthcare provider if you have concerns about fertility. These are not all the possible side effects of Pacerone tablets. For more information, ask your healthcare provider or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. How should I store Pacerone tablets? Store Pacerone tablets at room temperature between 20° to 25°C (68° to 77°F). Keep Pacerone tablets in a tightly closed container and keep Pacerone tablets out of the light. Pacerone comes in a child-resistant package. Keep Pacerone tablets and all medicines out of the reach of children. General information about the safe and effective use of Pacerone tablets Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use Pacerone tablets for a condition for which it was not prescribed. Do not give Pacerone tablets to other people, even if they have the same symptoms that you have. It may harm them. You can ask your pharmacist or healthcare provider for information about Pacerone tablets that is written for health professionals. What are the ingredients in Pacerone tablets? Active Ingredient : amiodarone hydrochloride Inactive Ingredients : lactose monohydrate, magnesium stearate, povidone, pregelatinized corn starch, sodium starch glycolate, stearic acid, FD&C Red No. 40 (200 mg) and FD&C Yellow No. 6 (100 mg and 200 mg). For more information and the most current Medication Guide, please visit www.upsher-smith.com or call 1-888-650-3789. This Medication Guide has been approved by the U.S. Food and Drug Administration. Manufactured by UPSHER-SMITH LABORATORIES, LLC Maple Grove, MN 55369 Pacerone is a registered trademark of Upsher-Smith Laboratories, LLC. Revised 5/2020

8.5 Geriatric Use Normal subjects over 65 years of age show lower clearances and increased drug half-life than younger subjects [see Clinical Pharmacology (12.3) ] . 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.

8.4 Pediatric Use The safety and effectiveness of Pacerone in pediatric patients have not been established.

8.1 Pregnancy Risk Summary Available data from post-marketing reports and published case series indicate that amiodarone use in pregnant women may increase the risk for fetal adverse effects including neonatal hypo- and hyperthyroidism, neonatal bradycardia, neurodevelopmental abnormalities, preterm birth and fetal growth restriction. Amiodarone and its metabolite, desethylamiodarone (DEA), cross the placenta. Untreated underlying arrhythmias, including ventricular arrhythmias, during pregnancy pose a risk to the mother and fetus (see Clinical Considerations ) . In animal studies, administration of amiodarone to rabbits, rats, and mice during organogenesis resulted in embryo-fetal toxicity at doses less than the maximum recommended human maintenance dose (see Data ) . Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss or other adverse outcomes. 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 Considerations Disease-associated maternal and/or embryo/fetal risk The incidence of ventricular tachycardia is increased and may be more symptomatic during pregnancy. Ventricular arrhythmias most often occur in pregnant women with underlying cardiomyopathy, congenital heart disease, valvular heart disease, or mitral valve prolapse. Most tachycardia episodes are initiated by ectopic beats and the occurrence of arrhythmia episodes may, therefore, increase during pregnancy due to the increased propensity to ectopic activity. Breakthrough arrhythmias may also occur during pregnancy, as therapeutic treatment levels may be difficult to maintain due to the increased volume of distribution and increased drug metabolism inherent in the pregnant state. Fetal/Neonatal adverse reactions Amiodarone and its metabolite have been shown to cross the placenta. Adverse fetal effects associated with maternal amiodarone use during pregnancy may 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 restriction, and premature birth. Monitor the newborn for signs and symptoms of thyroid disorder and cardiac arrhythmias. Labor and Delivery Risk of arrhythmias may increase during labor and delivery. Patients treated with Pacerone should be monitored continuously during labor and delivery [see Warnings and Precautions (5.4) ] . Data Animal Data In pregnant rats and rabbits during the period of organogenesis, amiodarone hydrochloride in doses of 25 mg/kg/day (approximately 0.4 and 0.9 times, respectively, the maximum recommended human maintenance dose 600 mg in a 60 kg patient (doses compared on a body surface area basis) ) had no adverse effects on the fetus. In the rabbit, 75 mg/kg/day (approximately 2.7 times the maximum recommended human maintenance dose ) caused abortions in greater than 90% of the animals. In the rat, doses of 50 mg/kg/day or more were associated with slight displacement of the testes and an increased incidence of incomplete ossification of some skull and digital bones; at 100 mg/kg/day or more, fetal body weights were reduced; at 200 mg/kg/day, there was an increased incidence of fetal resorption. (These doses in the rat are approximately 0.8, 1.6 and 3.2 times the maximum recommended human maintenance dose ) Adverse effects on fetal growth and survival also were noted in one of two strains of mice at a dose of 5 mg/kg/day (approximately 0.04 times the maximum recommended human maintenance dose ).

8 USE IN SPECIFIC POPULATIONS Pregnancy: May cause fetal harm. ( 8.1 ) Lactation: Breastfeeding not recommended. ( 8.2 ) 8.1 Pregnancy Risk Summary Available data from post-marketing reports and published case series indicate that amiodarone use in pregnant women may increase the risk for fetal adverse effects including neonatal hypo- and hyperthyroidism, neonatal bradycardia, neurodevelopmental abnormalities, preterm birth and fetal growth restriction. Amiodarone and its metabolite, desethylamiodarone (DEA), cross the placenta. Untreated underlying arrhythmias, including ventricular arrhythmias, during pregnancy pose a risk to the mother and fetus (see Clinical Considerations ) . In animal studies, administration of amiodarone to rabbits, rats, and mice during organogenesis resulted in embryo-fetal toxicity at doses less than the maximum recommended human maintenance dose (see Data ) . Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss or other adverse outcomes. 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 Considerations Disease-associated maternal and/or embryo/fetal risk The incidence of ventricular tachycardia is increased and may be more symptomatic during pregnancy. Ventricular arrhythmias most often occur in pregnant women with underlying cardiomyopathy, congenital heart disease, valvular heart disease, or mitral valve prolapse. Most tachycardia episodes are initiated by ectopic beats and the occurrence of arrhythmia episodes may, therefore, increase during pregnancy due to the increased propensity to ectopic activity. Breakthrough arrhythmias may also occur during pregnancy, as therapeutic treatment levels may be difficult to maintain due to the increased volume of distribution and increased drug metabolism inherent in the pregnant state. Fetal/Neonatal adverse reactions Amiodarone and its metabolite have been shown to cross the placenta. Adverse fetal effects associated with maternal amiodarone use during pregnancy may 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 restriction, and premature birth. Monitor the newborn for signs and symptoms of thyroid disorder and cardiac arrhythmias. Labor and Delivery Risk of arrhythmias may increase during labor and delivery. Patients treated with Pacerone should be monitored continuously during labor and delivery [see Warnings and Precautions (5.4) ] . Data Animal Data In pregnant rats and rabbits during the period of organogenesis, amiodarone hydrochloride in doses of 25 mg/kg/day (approximately 0.4 and 0.9 times, respectively, the maximum recommended human maintenance dose 600 mg in a 60 kg patient (doses compared on a body surface area basis) ) had no adverse effects on the fetus. In the rabbit, 75 mg/kg/day (approximately 2.7 times the maximum recommended human maintenance dose ) caused abortions in greater than 90% of the animals. In the rat, doses of 50 mg/kg/day or more were associated with slight displacement of the testes and an increased incidence of incomplete ossification of some skull and digital bones; at 100 mg/kg/day or more, fetal body weights were reduced; at 200 mg/kg/day, there was an increased incidence of fetal resorption. (These doses in the rat are approximately 0.8, 1.6 and 3.2 times the maximum recommended human maintenance dose ) Adverse effects on fetal growth and survival also were noted in one of two strains of mice at a dose of 5 mg/kg/day (approximately 0.04 times the maximum recommended human maintenance dose ). 8.2 Lactation Risk Summary Amiodarone and one of its major metabolites, DEA, are present in breastmilk at between 3.5% and 45% of the maternal weight-adjusted dosage of amiodarone. There are cases of hypothyroidism and bradycardia in breastfed infants, although it is unclear if these effects are due to amiodarone exposure in breastmilk. Breastfeeding is not recommended during treatment with Pacerone [see Warnings and Precautions (5.6 , 5.7) ] . 8.3 Females and Males of Reproductive Potential Infertility Based on animal fertility studies, amiodarone hydrochloride may reduce female and male fertility. It is not known if this effect is reversible [see Nonclinical Toxicology (13.1) ] . 8.4 Pediatric Use The safety and effectiveness of Pacerone in pediatric patients have not been established. 8.5 Geriatric Use Normal subjects over 65 years of age show lower clearances and increased drug half-life than younger subjects [see Clinical Pharmacology (12.3) ] . 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.

16 HOW SUPPLIED/STORAGE AND HANDLING Pacerone ® (amiodarone hydrochloride tablets, USP) 100 mg are peach, round, flat-faced, uncoated tablets, debossed with "P" on one side, and "U-S" above "144" on the other side. They are supplied as follows: Bottles of 30 with child-resistant closure, NDC 0245-0144-30 Bottles of 100 with child-resistant closure, NDC 0245-0144-11 Unit-dose cartons of 100 tablets, NDC 0245-0144-01 Pacerone ® (amiodarone hydrochloride tablets, USP) 200 mg, are pink, round, flat-faced, scored, uncoated tablets, debossed with "P 200 " on the unscored side, and "U-S" above and "0147" below the score on the reverse side. They are supplied as follows: Bottles of 60 with child-resistant closure, NDC 0245-0147-60 Bottles of 90 with child-resistant closure, NDC 0245-0147-90 Bottles of 500 tablets, NDC 0245-0147-15 Unit-dose cartons of 100 tablets, NDC 0245-0147-01 Pacerone ® (amiodarone hydrochloride tablets, USP) 400 mg, are white to off-white, round, uncoated, scored tablets, debossed with "U-S" above and "1645" below the score on one side and "P 400 " on the unscored side. They are supplied as follows: Bottles of 30 with child-resistant closure, NDC 0245-1645-30 Unit-dose cartons of 100 tablets, NDC 0245-1645-01 Keep tightly closed. Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature]. Protect from light. Dispense in a tight, light-resistant container with a child-resistant closure.

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature]. Protect from light. Dispense in a tight, light-resistant container with a child-resistant closure.

WARNING: PULMONARY, HEPATIC and CARDIAC TOXICITY Pacerone is intended for use only in patients with the indicated life-threatening arrhythmias because its use is accompanied by substantial toxicity [see Indications and Usage (1) ] . Pacerone can cause pulmonary toxicity (hypersensitivity pneumonitis or interstitial/alveolar pneumonitis) that has resulted in clinically manifest disease at rates as high as 17% in some series of patients. Pulmonary toxicity has been fatal about 10% of the time . Obtain a baseline chest X-ray and pulmonary-function tests, including diffusion capacity, when Pacerone therapy is initiated. Repeat history, physical exam, and chest X-ray every 3 to 6 months [see Warnings and Precautions 5.2) ] . Pacerone can cause hepatoxicity, which can be fatal. Obtain baseline and periodic liver transaminases and discontinue or reduce dose if the increase exceeds three times normal, or doubles in a patient with an elevated baseline. Discontinue Pacerone if the patient experiences signs or symptoms of clinical liver injury [see Warnings and Precautions (5.3) ] . Pacerone can exacerbate arrhythmias. Initiate amiodarone hydrochloride in a clinical setting where continuous electrocardiograms and cardiac resuscitation are available [see Warnings and Precautions (5.4) ] . WARNING: PULMONARY, HEPATIC, and CARDIAC TOXICITY See full prescribing information for complete boxed warning. Reserve Pacerone for patients with the indicated life-threatening arrhythmias because its use is accompanied by substantial toxicity, some also life-threatening. Utilize alternative agents first. ( 1 ) Pacerone' s life-threatening toxicities include pulmonary ( 5.2 ), hepatic ( 5.3 ), and proarrhythmic ( 5.4 ). Initiate under hospital or specialist supervision. ( 5 )