Amiodarone belongs to the family of medications known as antiarrhythmics. It is used to treat certain types of abnormal heart rhythms (arrhythmias). It works by changing how electrical impulses affect the heart muscle and by making the heart beat more regularly. The effects of this medication may be noted as early as 3 days after starting treatment, but it is usually 1 to 3 weeks before beneficial effects are seen.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult starting dose of amiodarone is usually from 800 mg to 1,600 mg daily for the first 1 to 3 weeks in divided doses. The dose is eventually reduced to 200 mg to 400 mg once daily as prescribed by your doctor and according to circumstances. This medication may be taken with or without meals, but should be taken in the same manner each day. Do not take grapefruit juice during amiodarone treatment because blood levels of amiodarone may increase, causing an increase in side effects.

The injectable form of amiodarone may be used in hospitals under specific circumstances. The recommended dose varies according to individual circumstances.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed or skipped dose. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Each pink, flat-faced, bevelled-edge tablet, engraved "AMI" over score "200" on one side and "APO" on the other side, contains 200 mg of amiodarone hydrochloride. Nonmedicinal ingredients: crospovidone, croscarmellose sodium, colloidal silicon dioxide, FD&C Red No. 40 Aluminum Lake 38-42%, and magnesium stearate.

Do not use this medication if you:

• are allergic to amiodarone, iodine, or any ingredients of this medication
• are in cardiogenic shock
• have a very low heart rate
• have certain lung problems
• have hepatitis
• have second or third degree AV block (except when used with a pacemaker)
• have thyroid disease

Do not give this medication to people in cardiogenic shock.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• bad taste
• constipation
• diarrhea
• difficulty sleeping
• dizziness or lightheadedness
• muscle weakness
• nausea
• sensitivity of skin to sunlight
• tremor
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blue-grey colouring of skin on face, neck, and arms
• blurred vision or blue-green halos seen around objects
• confusion
• decreased coordination
• dizziness or fainting
• goiter (lump on neck)
• hair loss
• inability to concentrate
• low blood pressure
• numbness or tingling in fingers or toes
• sensitivity of eyes to light
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of liver problems, e.g.:
  • abdominal pain or swelling
  • dark urine
  • fever
  • itchy skin
  • loss of appetite
  • nausea and vomiting
  • pale or clay-coloured stools
  • yellowing of skin or whites of eyes
• skin rash
• slow heartbeat
• swelling of feet or lower legs
• symptoms of overactive thyroid gland (e.g., nervousness, rapid heartbeat, hand tremor, weight loss, and problems sleeping)
• symptoms of underactive thyroid gland (e.g., dry skin, constipation, weight gain, fatigue, aches, pains and stiffness, intolerance to cold, depression, memory problems)
• trembling or shaking hands
• trouble walking
• unusual and uncontrolled body movements
• vision loss
• weight loss

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of an irregular heartbeat (e.g., fainting, dizziness, light-headedness, weakness or chest pain)
• fast or irregular heartbeat
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• signs of a severe allergic reaction, e.g.:
  • hives
  • shortness of breath
  • swelling of the lips, tongue, or throat
• signs of lung problems, e.g.:
  • cough
  • coughing-up of blood
  • difficulty breathing
  • fever
  • shortness of breath
  • wheezing

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythm: Amiodarone may cause a heart rhythm disturbance called QT prolongation. It can also worsen or trigger an irregular heartbeat (arrhythmia). Your doctor will monitor your heart rhythm regularly while you are taking this medication with a test called an electrocardiogram (ECG).
Certain medications (e.g., sotalol, thioridazine, chlorpromazine, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, dolasetron mesylate, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should only be used in combination with amiodarone if the benefit of receiving both medications outweighs the risk of side effects. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

Blood potassium and magnesium levels: People with low levels of potassium or magnesium should have these conditions corrected before starting amiodarone, as the risk of worsening abnormal heart rhythms may be increased.

Congestive heart failure: Amiodarone may cause congestive heart failure to worsen. If you have congestive heart failure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

General: Due to the potential for serious side effects, amiodarone should only be given by physicians who are experienced in the treatment of abnormal heart rhythms.

Liver disease: Amiodarone may cause liver problems, so your doctor should monitor your liver function regularly. If you have liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. People with hepatitis should not take amiodarone.

Lung problems: Amiodarone can cause lung problems (pulmonary fibrosis, permanent scarring of the lungs) that, in some cases, can be fatal. If you experience any difficulty breathing, wheezing, fever, shortness of breath, cough, or coughing up of blood, accompanied by weakness and weight loss while taking amiodarone, tell your doctor immediately.

Skin: Amiodarone may make your skin more sensitive to the sun. Use sunscreen with minimum SPF15 and protective clothing while taking amiodarone. Some people using amiodarone for long-term treatment may develop a blue-grey discoloration of exposed skin. Report any changes in skin colour to your doctor.

Surgery: If you are scheduled for surgery, inform all doctors involved in your care that you are taking amiodarone.

Thyroid disease: Amiodarone can cause thyroid problems (both overactive and underactive). Your doctor will perform tests regularly to monitor your thyroid function prior to and during amiodarone treatment, especially if you are a senior or if you have a history of thyroid problems.

Vision problems: Amiodarone may cause vision problems that may be severe or permanent. Regular eye exams are recommended during amiodarone treatment. If you notice any vision changes or problems, contact your doctor as soon as possible.

Pregnancy: Amiodarone may harm a developing baby if it is taken during pregnancy. In particular, it has been noted to cause thyroid problems for the baby. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and taking amiodarone, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of amiodarone for use by children have not been established.

Seniors:  People over the age of 65 may require lower doses of amiodarone.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.