Generic Name

Amiodarone

Brand Names

Pacerone, Nexterone, Amiodarone HCI

FDA approval date: March 30, 2001

Classification: Antiarrhythmic

Form: Injection, Tablet

What is Pacerone (Amiodarone)?

Amiodarone

Introduction to Amiodarone

Living with an irregular heartbeat can be frightening, especially when episodes come unexpectedly, causing palpitations, dizziness, or even fainting. For people with serious heart rhythm problems (arrhythmias), controlling these abnormal beats can prevent dangerous complications such as fainting, stroke, or cardiac arrest. Amiodarone is a long-established medication that helps the heart maintain a steady rhythm when other treatments havent worked or arent suitable.

Amiodarone belongs to a group of medicines called antiarrhythmics, which correct irregular heartbeats. Its most often prescribed for ventricular arrhythmias (irregular heartbeats that begin in the lower chambers) or atrial fibrillation/flutter (abnormal rhythms in the upper chambers). Doctors usually reserve Amiodarone for severe or potentially life-threatening rhythm disturbances, since its one of the most potent rhythm-control medications available.

What Does Amiodarone Do?

Amiodarone helps restore and maintain a normal heart rhythm in people whose heartbeat is dangerously fast or irregular. Its often used when other antiarrhythmic drugs such as sotalol or flecainide are ineffective or poorly tolerated.

This drug treats fast heart rhythms including:

Ventricular tachycardia (VT): A rapid rhythm from the lower chambers
Ventricular fibrillation (VF): A chaotic rhythm that can cause cardiac arrest
Atrial fibrillation (AFib): An upper-chamber rhythm that increases stroke risk
Atrial flutter: A rapid but more organized rhythm from the upper chambers

For some patients, especially those with heart failure or prior heart attack, Amiodarone can reduce hospitalizations and the risk of sudden cardiac death. Clinical studies have shown that Amiodarone helps maintain sinus rhythm longer than most other antiarrhythmic drugs, though close monitoring is required for safety (U.S. Food and Drug Administration [FDA], 2023; Mayo Clinic, 2024).

How Does Amiodarone Work?

Amiodarone works by slowing abnormal electrical signals in the heart, helping the heartbeat return to a normal and steady rhythm.

To understand this, think of the heart as a synchronized electrical system. In arrhythmias, those electrical impulses become erratic, firing too fast or in the wrong place. Amiodarone blocks several electrical channels in heart muscle cells (including potassium, sodium, and calcium channels) and slightly slows nerve conduction, giving the heart time to reset between beats.

This means the drug helps prevent sudden bursts of fast heart rate or chaotic rhythms that can lead to collapse or cardiac arrest. It also reduces the hearts oxygen demand, which is especially helpful for patients with underlying heart disease.

What makes Amiodarone unique is its broad mechanism of actionit works in multiple ways. Though classified as a Class III antiarrhythmic, it also has properties of all four Vaughan-Williams classes. This versatility explains why it remains a go-to treatment when others fail.

Side Effects of Amiodarone

Because Amiodarone acts on many parts of the body and stays in tissues for a long time, it can cause a wide range of side effects. Most are mild and reversible with dose adjustment, but serious reactions can occur, particularly with long-term use.

Common Side Effects

Fatigue, dizziness, or nausea
Sensitivity to sunlight or bluish skin discoloration
Tremor, tingling, or coordination problems
Mild visual changes (seeing halos around lights)

Serious Side Effects

Lung toxicity (pneumonitis or fibrosis): Persistent cough, shortness of breath, or chest pain should be reported immediately.
Thyroid problems: Amiodarone contains iodine and can cause either overactive or underactive thyroid function.
Liver injury: Signs include yellowing of the skin or eyes, dark urine, or unusual fatigue.
Eye changes: Corneal deposits are common but harmless; rarely, optic nerve damage can occur.
Heart effects: Excess slowing of the heart rate or worsening arrhythmia.

Because the drug can affect several organs, regular blood tests, chest X-rays, and eye exams are essential during treatment (MedlinePlus, 2024; NIH, 2023).

Who Should Avoid Amiodarone?

People with severe sinus node disease or heart block (unless they have a pacemaker)
Those with iodine allergy or severe thyroid disease
Pregnant women (Amiodarone may harm the unborn baby)

Seek immediate medical help if you experience shortness of breath, swelling, fainting, or vision loss.

Amiodarone Dosage

Amiodarone comes in oral and IV forms. Treatment starts with a loading phase, followed by a maintenance dose. It builds up and clears slowly, so effects and side effects can take weeks to appear and months to vanish.

Doctors monitor lung, thyroid, liver, and kidney function, vision, heart rhythm, and electrolytes every 612 months for safety. Older adults or those with liver or lung disease may need lower doses. Grapefruit juice or certain antibiotics can increase toxicity, so its important to check drug interactions regularly.

Does Amiodarone Have a Generic Version?

Yes. Amiodarone is available in generic form, approved by the U.S. FDA and widely used worldwide. The brand name versions include Cordarone and Pacerone, but generic Amiodarone contains the same active ingredient and has been proven to be equally effective and safe.

Generics are typically more affordable, making long-term therapy accessible for most patients. Some people may notice different tablet colors or shapes depending on the manufacturer, but the medications action remains the same.

Conclusion

Amiodarone remains one of the most effective medications for managing serious or life-threatening heart rhythm disorders, especially when other drugs fall short. Its unique, multi-channel blocking action helps stabilize dangerous arrhythmias and prevent cardiac complications.

When prescribed and managed by a qualified healthcare provider, Amiodarone can be lifesaving, helping people with severe arrhythmias live longer, safer, and more active lives. Staying informed, following your doctors guidance, and reporting new symptoms promptly are key to getting the best results from this powerful heart rhythm medication.

References

Mayo Clinic. (2024). Amiodarone (oral route) Description and precautions. Retrieved from https://www.mayoclinic.org
MedlinePlus. (2024). Amiodarone Drug information. U.S. National Library of Medicine. Retrieved from https://medlineplus.gov/druginfo/meds/a687009.html
U.S. Food and Drug Administration. (2023). Amiodarone Hydrochloride labeling information. Retrieved from https://www.accessdata.fda.gov
National Institutes of Health. (2023). Amiodarone Drug record. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Retrieved from https://www.nih.gov/
American Heart Association. (2024). Treatment options for arrhythmia. Retrieved from https://www.heart.org

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Brand Information

Pacerone (Amiodarone Hydrochloride)

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

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

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

Pacerone can exacerbate arrhythmias. Initiate amiodarone hydrochloride in a clinical setting where continuous electrocardiograms and cardiac resuscitation are available

1INDICATIONS 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.

2DOSAGE 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.

3DOSAGE 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

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

4CONTRAINDICATIONS

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.

5ADVERSE REACTIONS

The following serious adverse reactions are described in more detail in other sections of the prescribing information:

Pulmonary Toxicity
Hepatic Injury
Worsened Arrhythmia
Visual Impairment and Loss of Vision
Thyroid Abnormalities
Bradycardia
Peripheral Neuropathy
Photosensitivity and Skin Discoloration

5.1Clinical 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.

5.2Post-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.

6DRUG 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.

7OVERDOSAGE

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.

8DESCRIPTION

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:

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.

9HOW SUPPLIED/STORAGE AND HANDLING

Pacerone

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

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

Bottles of 30 with child-resistant closure, NDC 0245-1645-30

Unit-dose cartons of 100 tablets, NDC 0245-1645-01

Keep tightly closed.

10PATIENT 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

Advise women that breastfeeding is not recommended during treatment with Pacerone

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.

11Repackaging Information

Please reference the

Store between 20°-25°C (68°-77°F). See USP Controlled Room Temperature. Dispense in a tight light-resistant container as defined by USP. Keep this and all drugs out of the reach of children.

Repackaged by:

12PRINCIPAL DISPLAY PANEL - 200 mg

NDC 71610-787 - Amiodarone HCl (Pacerone) 200 mg Tablets - Rx Only