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Amiodarone

Generic Name: amiodarone tablets (oral) (A mi OH da rone)
Brand Names: Pacerone

Medically reviewed by P. Thornton, DipPharm. Last updated on Feb 17, 2019.

In summary

Amiodarone is an antiarrhythmic drug used to treat and prevent ventricular arrhythmias. It works by blocking the electrical signals in the heart that can cause an irregular heartbeat. It is available in tablet form under the brand name Pacerone, and is also available as a generic.

Common side effects include: nausea, vomiting, and loss of appetite.

What is amiodarone?

Amiodarone affects the rhythm of your heartbeats. It is used to help keep the heart beating normally in people with life-threatening heart rhythm disorders of the ventricles (the lower chambers of the heart that allow blood to flow out of the heart).

Amiodarone is used to treat ventricular tachycardia or ventricular fibrillation.

Amiodarone is for use only in treating life-threatening heart rhythm disorders.

Important Information

Amiodarone can cause dangerous side effects on your heart, liver, lungs, or vision.

You should not take this medicine if you are allergic to amiodarone or iodine, or if you have heart block, a history of slow heartbeats that have caused you to faint, or if your heart cannot pump blood properly.

Call your doctor or get medical help at once if you have: chest pain, fast or pounding heartbeats, trouble breathing, vision problems, upper stomach pain, vomiting, dark urine, jaundice (yellowing of the skin or eyes), or if you cough up blood.

Tell your doctor if you have signs of a thyroid problem, such as weight changes, extreme tiredness, dry skin, thinning hair, feeling too hot or too cold, irregular menstrual periods, or swelling in your neck (goiter).

Before taking this medicine

You should not use amiodarone if you have:

  • a serious heart condition called "AV block" (2nd or 3rd degree), unless you have a pacemaker;
  • a history of slow heartbeats that have caused you to faint; or
  • if your heart cannot pump blood properly.

Amiodarone can cause dangerous side effects on your heart, liver, lungs, or thyroid.

To make sure this medicine is safe for you, tell your doctor if you have ever had:

  • asthma or another lung disorder;
  • liver disease;
  • a thyroid disorder;
  • vision problems;
  • high or low blood pressure;
  • an electrolyte imbalance (such as low levels of potassium or magnesium in your blood); or
  • if you have a pacemaker or defibrillator implanted in your chest.

Taking amiodarone during pregnancy may harm an unborn baby, or cause thyroid problems or abnormal heartbeats in the baby after it is born. Amiodarone may also affect the child's growth or development (speech, movement, academic skills) later in life. Tell your doctor if you are pregnant or if you become pregnant.

You should not breast-feed while taking this medicine, and for several months after stopping. Amiodarone takes a long time to clear from your body. Talk to your doctor about the best way to feed your baby during this time.

How should I take amiodarone?

Take amiodarone exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

You will receive your first few doses in a hospital setting, where your heart rhythm can be monitored.

If you have been taking another heart rhythm medicine, you may need to gradually stop taking it when you start using amiodarone. Follow your doctor's dosing instructions very carefully.

You may take the tablets with or without food, but take it the same way each time.

It may take up to 3 weeks before your heart rhythm improves. Keep using the medicine as directed even if you feel well.

Amiodarone can have long lasting effects on your body. You may need frequent medical tests while using this medicine and for several months after your last dose.

If you need surgery (including laser eye surgery), tell the surgeon ahead of time that you are using amiodarone.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using this medicine.

Store at room temperature away from moisture, heat, and light.

Amiodarone dosing information Pro

Applies to the following strengths: 50 mg/mL; 200 mg; 300 mg; 100 mg; 400 mg; 150 mg/100 mL-D5%; 900 mg/500 mL-D5%; 450 mg/250 mL-D5%; 360 mg/200 mL-D5%

Usual adult dose for arrhythmias

IV:

  • Initial dose: 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen:
    • Loading infusions: 150 mg over the first 10 minutes (15 mg/min), followed by 360 mg over the next 6 hours (1 mg/min)
    • Maintenance infusion: 540 mg over the remaining 18 hours (0.5 mg/min)
  • Maintenance dose: After the first 24 hours, continue the maintenance infusion rate of 0.5 mg/min; may increase infusion rate to achieve effective arrhythmia suppression.
    • Supplemental infusions: 150 mg over 10 minutes (15 mg/min) for breakthrough episodes of ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT)
  • Maximum dose: Initial infusion rate: 30 mg/min
  • Duration of therapy: Until ventricular arrhythmias stabilize (most patients require 48 to 96 hours); maintenance infusion of up to 0.5 mg/min can be continued for up to 3 weeks.
  • Comments: Mean daily doses greater than 2100 mg for the first 24 hours were associated with increased risk of hypotension.
  • Use: Initiation of treatment and prophylaxis of frequently recurring VF and hemodynamically unstable VT in patients refractory to other therapy.

ORAL:

  • Loading dose: 800 to 1600 mg orally per day for 1 to 3 weeks (occasionally longer) until adequate arrhythmia control is achieved or if side effects become prominent, then switch to adjustment dose
  • Adjustment dose: 600 to 800 mg orally per day for 1 month, then switch to maintenance dose
  • Maintenance dose: 400 mg orally per day

Comments:

  • May be administered once a day; twice a day dosing is recommended for total daily doses of 1000 mg or more or in patients who experience gastrointestinal tolerance.
  • Close monitoring is indicated during the loading phase and surrounding any dose adjustments.
  • Maintenance dose should be determined according to antiarrhythmic effect as assessed by patient tolerance as well as symptoms, Holter recordings, and/or programmed electrical stimulation; some patients may require up to 600 mg/day while some can be controlled on lower doses.

Use: Treatment of life-threatening recurrent VF or life-threatening recurrent hemodynamically unstable VT in patients refractory to adequate doses of other antiarrhythmics or those intolerant of alternative agents.

Renal dose adjustments

  • No adjustment recommended

Liver dose adjustments

  • No adjustment recommended
  • If progressive hepatic injury or hepatomegaly occurs or hepatic enzyme levels increase to greater than 3 times normal (or double in a patient with elevated baseline levels): Consider dose reduction or discontinuation.

Dose adjustments

  • This drug should be used at the lowest effective dose in order to prevent the occurrence of side effects.
  • IV to oral transition (infusion duration [assuming 0.5 mg/min infusion]: initial oral daily dose)
    • Less than one week: 800 to 1600 mg
    • One to three weeks: 600 to 800 mg
    • Greater than three weeks: 400 mg
  • Therapeutic drug range: No well-established relationship exists between drug concentration and therapeutic response; however, concentrations much below 1 mg/L are often ineffective and levels above 2.5 mg/L are usually unnecessary.

Precautions

US BOXED WARNINGS (TABLET): These effects may also be seen with IV administration.

FATAL TOXICITY: This drug is intended for use only in patients with the indicated life-threatening arrhythmias because its use is accompanied by substantial toxicity. Even in patients at high risk of arrhythmic death, in whom the toxicity of this drug is an acceptable risk, this drug poses major management problems that could be life-threatening in a population at risk of sudden death, so that every effort should be made to utilize alternative agents first. The difficulty of using this drug safely and effectively itself poses a significant risk to patients. Patients with the indicated arrhythmias must be hospitalized while the loading dose is given, and a response generally requires at least one week, usually two or more. Because absorption and elimination are variable, maintenance-dose selection is difficult, and it is not unusual to require dosage decrease or discontinuation of treatment. In a retrospective survey of 192 patients with ventricular tachyarrhythmias, 84 required dose reduction and 18 required at least temporary discontinuation because of adverse effects, and several series have reported 15% to 20% overall frequencies of discontinuation due to adverse reactions. The time at which a previously controlled life-threatening arrhythmia will recur after discontinuation or dose adjustment is unpredictable, ranging from weeks to months. The patient is obviously at great risk during this time and may need prolonged hospitalization. Attempts to substitute other antiarrhythmic agents when this drug must be stopped will be made difficult by the gradually, but unpredictably, changing body burden of this drug. A similar problem exists when this drug is not effective; it still poses the risk of an interaction with whatever subsequent treatment is tried.

HEPATOTOXICITY: Liver injury is common with this drug, but is usually mild and evidenced only by abnormal liver enzymes. Overt liver disease can occur, however, and has been fatal in a few cases. 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 this drug if the patient experiences signs or symptoms of clinical liver injury.

PROARRHYTHMIC EFFECTS: Like other antiarrhythmics, this drug can exacerbate the arrhythmia, e.g., by making the arrhythmia less well tolerated or more difficult to reverse. This has occurred in 2% to 5% of patients in various series, and significant heart block or sinus bradycardia has been seen in 2% to 5%. All of these events should be manageable in the proper clinical setting in most cases. Although the frequency of such proarrhythmic events does not appear greater with this drug than with many other agents used in this population, the effects are prolonged when they occur. Initiate this drug in a clinical setting where continuous ECGs and cardiac resuscitation are available.

PULMONARY TOXICITY: This drug has several potentially fatal toxicities, the most important of which is pulmonary toxicity (hypersensitivity pneumonitis or interstitial/alveolar pneumonitis) that has resulted in clinically manifest disease at rates as high as 10% to 17% in some series of patients with ventricular arrhythmias given doses around 400 mg/day, and as abnormal diffusion capacity without symptoms in a much higher percentage 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 treatment with this drug is initiated. Repeat history, physical exam, and chest X-ray every 3 to 6 months.

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

  • Data not available

Other comments

  • Administration advice: The manufacturer product information should be consulted.
  • Storage requirements: The manufacturer product information should be consulted.
  • Reconstitution/preparation techniques: The manufacturer product information should be consulted.
  • IV compatibility: The manufacturer product information should be consulted.

Monitoring:

  • Cardiovascular: ECG and blood pressure
  • Endocrine: Thyroid function tests
  • Hepatic: Liver function tests
  • Metabolic: Baseline serum potassium
  • Ocular: Ophthalmic examination, including fundoscopy and slit-lamp examination
  • Respiratory: History, physical exam, chest X-ray, and pulmonary function tests, including diffusion capacity

Patient advice:

  • Inform patients administering this drug to do so consistently with regard to meals.
  • Advise patients to avoid consumption of grapefruit juice during treatment with this drug.
  • Instruct patients to avoid sun exposure and use sun-barrier creams or protective clothing.
  • Advise patients to moderate alcohol consumption while taking this drug.
  • If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus.
  • Advise patients that most manufacturers of corneal refractive laser surgery devices consider corneal refractive laser surgery contraindicated in patients taking this drug.

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of amiodarone can be fatal.

Overdose symptoms may include weakness, slow heart rate, feeling light-headed, or loss of consciousness.

What should I avoid while taking amiodarone?

Avoid driving or hazardous activity until you know how amiodarone will affect you. Your reactions could be impaired.

Grapefruit may interact with amiodarone and lead to unwanted side effects. Avoid the use of grapefruit products.

Avoid taking an herbal supplement containing St. John's wort.

Amiodarone could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Pregnancy and breastfeeding data Pro

Amiodarone pregnancy warnings

Use is considered contraindicated and should be used during pregnancy only if the benefit outweighs the risk.

AU TGA pregnancy category: C
US FDA pregnancy category: D (IV); Not assigned (tablets)

Risk Summary: Use in pregnant women may increase the risk of adverse fetal effects (e.g., neonatal hypo- and hyperthyroidism, neonatal bradycardia, neurodevelopmental abnormalities, preterm birth, and fetal growth restriction). Untreated underlying arrhythmias in pregnant women pose a risk to the mother and fetus.

Comments:
-If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus.
-Patients planning pregnancy should be advised of the long half-life associated with this drug and its metabolite.
-Therapeutic levels may be difficult to maintain due to the increased volume of distribution and increased drug metabolism inherent in the pregnant state.
-Monitor the newborn for signs and symptoms of thyroid disorder and cardiac arrhythmias.

Animal studies have revealed evidence of embryofetal toxicity at doses less than the maximum recommended human maintenance dose. In humans, congenital goiter/hypothyroidism, hyperthyroidism, and neonatal bradycardia have been reported. There are no controlled data in human pregnancy.

Risk of arrhythmias may increase during labor and delivery; monitor patients continuously during labor and delivery.

AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.

US FDA pregnancy category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

Amiodarone breastfeeding warnings

The infant receives an estimated dose of this drug plus its active metabolite between 3.5% and 45% of the maternal weight-adjusted dosage, with a median dose of approximately 11%. Infant serum levels of this drug plus metabolite range from 14% to 74% of simultaneous maternal levels (the higher values reflect transplacental passage of the drug). Some authorities believe this drug can be used during breastfeeding with periodic monitoring of infant cardiac and thyroid function, especially if only one dose is administered.

Breastfeeding is not recommended during use of this drug; use is contraindicated per some authorities.

Excreted into human milk: Yes

See references

Amiodarone side effects

Get emergency medical help if you have signs of an allergic reaction to amiodarone: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Amiodarone takes a long time to completely clear from your body. You may continue to have side effects from this medicine after you stop using it.

Call your doctor at once if you have any of these side effects, even if they occur up to several months after you stop using this medicine:

  • wheezing, cough, chest pain, cough with bloody mucus, fever;
  • a new or a worsening irregular heartbeat pattern (fast, slow, or pounding heartbeats);
  • a light-headed feeling, like you might pass out;
  • blurred vision, seeing halos around lights (your eyes may be more sensitive to light);
  • liver problems - nausea, vomiting, stomach pain (upper right side), tiredness, dark urine, jaundice (yellowing of the skin or eyes);
  • nerve problems - loss of coordination, muscle weakness, uncontrolled muscle movement, or a prickly feeling in your hands or lower legs;
  • signs of overactive thyroid - weight loss, thinning hair, feeling hot, increased sweating, tremors, feeling nervous or irritable, irregular menstrual periods, swelling in your neck (goiter); or
  • signs of underactive thyroid - weight gain, tiredness, depression, trouble concentrating, feeling cold.

Common amiodarone side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Side effects by body system Pro

Applies to amiodarone: compounding powder, intravenous solution, oral tablet

General

  • The most common adverse reactions were corneal microdeposits, hypotension, and photosensitivity.[Ref]

Cardiovascular

  • Very common (10% or more): Hypotension (up to 20.2%)
  • Common (1% to 10%): Bradycardia, blood pressure decreased, congestive heart failure, heart arrest, ventricular tachycardia, cardiac arrhythmia, sinoatrial node dysfunction, flushing
  • Uncommon (0.1% to 1%): Conduction disturbances
  • Very rare (less than 0.01%): Marked bradycardia, sinus arrest, vasculitis, hot flushes
  • Frequency not reported: Torsade de pointes, collapse, atrial fibrillation, nodal arrhythmia, QT interval prolonged, sinus bradycardia, ventricular fibrillation, shock, asystole, pulseless electrical activity, cardiogenic shock, atrioventricular block, severe hypotension
  • Postmarketing reports: Sinoatrial block, intraventricular conduction disorders, bundle branch block, infra-His block, ventricular extrasystole, antegrade conduction via an accessory pathway[Ref]

Hepatic

  • Common (1% to 10%): Acute liver disorders with high serum transaminases and/or jaundice including hepatic failure, liver function tests abnormal, nonspecific hepatic disorder
  • Very rare (less than 0.01%): Pseudo alcoholic hepatitis, cirrhosis, serum transaminases increased
  • Frequency not reported: ALT increased, AST increased
  • Postmarketing reports: Cholestatic hepatitis, cholestasis, jaundice, alkaline phosphatase increased, blood lactate dehydrogenase increased, hepatitis[Ref]

Respiratory

Ocular

  • Very common (10% or more): Corneal microdeposits (up to 90% or more)
  • Common (1% to 10%): Visual disturbance
  • Very rare (less than 0.01%): Optic neuropathy/neuritis
  • Frequency not reported: Permanent blindness, papilledema, corneal degeneration, eye discomfort, scotoma, lens opacities, macular degeneration, keratopathy, gritty eyes, itching, burning
  • Postmarketing reports: Visual field defect, blurred vision[Ref]

Dermatologic

Nervous system

  • Common (1% to 10%): Extrapyramidal symptoms, extrapyramidal tremor, tremor/abnormal involuntary movement, lack of coordination, gait abnormal/ataxia, dizziness, paresthesia, headache, abnormal taste and smell
  • Uncommon (0.1% to 1%): Peripheral sensorimotor neuropathy
  • Very rare (less than 0.01%): Cerebellar ataxia, benign intracranial hypertension, vertigo
  • Frequency not reported: Peripheral neuropathy, demyelinating polyneuropathy, nerve conduction abnormal, neurolipidosis, neuromyopathy, parosmia
  • Postmarketing reports: Confusional state, disorientation, delirium, intracranial pressure increased, hypoesthesia, Parkinsonian symptoms[Ref]

Psychiatric

  • Common (1% to 10%): Nightmare, sleep disorders, libido decreased, insomnia, sleep disturbance
  • Frequency not reported: Vivid dreams, chronic anxiety
  • Postmarketing reports: Hallucination[Ref]

Gastrointestinal

  • Common (1% to 10%): Nausea, constipation, abdominal pain, salivation abnormal
  • Frequency not reported: Vomiting, dysgeusia, diarrhea
  • Postmarketing reports: Pancreatitis, acute pancreatitis, dry mouth[Ref]

Other

  • Common (1% to 10%): Fever, malaise, fatigue[Ref]

Endocrine

  • Very common (10% or more): Hypothyroidism (up to 10%)
  • Common (1% to 10%): Hyperthyroidism
  • Very rare (less than 0.01%): Syndrome of inappropriate antidiuretic hormone secretion
  • Frequency not reported: Thyroid function tests abnormal
  • Postmarketing reports: Thyroid nodules/cancer[Ref]

Metabolic

  • Common (1% to 10%): Anorexia, edema
  • Frequency not reported: Weight gain, symptomatic hypercalcemia, appetite decreased[Ref]

Hematologic

Musculoskeletal

  • Common (1% to 10%): Muscle weakness
  • Frequency not reported: Back pain
  • Postmarketing reports: Myopathy, rhabdomyolysis, muscle spasm, lupus-like syndrome[Ref]

Local

  • Common (1% to 10%): Injection site reactions[Ref]

Genitourinary

Immunologic

  • Very rare (less than 0.01%): Anaphylactic shock
  • Frequency not reported: Hypersensitivity reaction, positive antinuclear antibodies, immunoglobulin level increased
  • Postmarketing reports: Anaphylactic/anaphylactoid reaction[Ref]

Renal

  • Very rare (less than 0.01%): Blood creatinine increased
  • Frequency not reported: Kidney function abnormal, chronic renal failure worsened
  • Postmarketing reports: Renal impairment, renal insufficiency, acute renal failure[Ref]

What other drugs will affect amiodarone?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Amiodarone takes a long time to completely clear from your body. Drug interactions are possible for up to several months after you stop using amiodarone. Talk to your doctor before taking any medication during this time. Keep track of how long it has been since your last dose of amiodarone.

Many drugs can interact with amiodarone. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any medicine you start or stop using.

Amiodarone drug interactions Pro

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use amiodarone only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Side effects references

  1. "Product Information. Cordarone (amiodarone)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. "Product Information. Cordarone Intravenous (amiodarone)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

References for pregnancy information

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. "Product Information. Cordarone Intravenous (amiodarone)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
  4. "Product Information. Cordarone (amiodarone)." Wyeth-Ayerst Laboratories, Philadelphia, PA.

References for breastfeeding information

  1. "Product Information. Cordarone Intravenous (amiodarone)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
  2. United States National Library of Medicine "Toxnet. Toxicology Data Network. Available from: URL: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT." ([cited 2013 -]):
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. "Product Information. Cordarone (amiodarone)." Wyeth-Ayerst Laboratories, Philadelphia, PA.
  5. Cerner Multum, Inc. "Australian Product Information." O 0
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