BMA Concise Guide to Medicine & Drugs

Amiodarone

Brand name Cordarone X

Used in the following combined preparations None

QUICK REFERENCE

Drug group Anti-arrhythmic drug

Overdose danger rating High

Dependence rating Low

Prescription needed Yes

Available as generic Yes (tablets)

GENERAL INFORMATION

Amiodarone is used to treat a variety of abnormal heart rhythms (arrhythmias). It works by slowing nerve impulses in the heart muscle. Amiodarone is given to prevent recurrent atrial and ventricular fibrillation and to treat ventricular and supraventricular tachycardias and Wolff-Parkinson-White syndrome. Often the last choice when other treatments have failed, especially for long-term use, it has serious adverse effects including liver damage, thyroid problems, and eye and lung damage. Treatment should be started only under specialist supervision or in hospital.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, injection.

Frequency and timing of doses 3 x daily or by injection initially, then reduced to twice daily, then once daily or every other day (maintenance dose).

Adult dosage range 600mg daily, reduced to 400mg, then 100–200mg daily.

Onset of effect By mouth, some effects may occur in 72 hours; full benefits may take some weeks to show. By injection, effects may occur within 30 minutes.

Duration of action 3–12 months.

Diet advice Grapefruit juice should be avoided.

Storage Keep in original container at room temperature out of the reach of children. Protect from light.

Missed dose Take as soon as you remember. If your next dose is due within 12 hours, do not take the missed dose. Take your next scheduled dose as usual.

Stopping the drug Do not stop the drug without consulting your doctor; symptoms may recur.

OVERDOSE ACTION

Seek immediate medical advice in all cases. Take emergency action if collapse or loss of consciousness occur.

POSSIBLE ADVERSE EFFECTS

Amiodarone has a number of unusual side effects, including a metallic taste in the mouth, a greyish skin colour (on prolonged use), and increased sensitivity of the skin to sunlight. The drug can also cause nausea and vomiting; liver damage; visual disturbances; thyroid problems; heart rate disturbances; numbness and tingling in the extremities; shortness of breath; a cough; headache; weakness; and fatigue. Discuss with your doctor if nausea and vomiting are severe or if any other adverse effects occur.

INTERACTIONS

General note Amiodarone can interact with many drugs. Consult your doctor or pharmacist before taking other medications.

Diuretics The potassium loss caused by some of these drugs may increase the toxic effects of amiodarone.

Other anti-arrhythmic drugs Amiodarone may increase the effects of drugs such as beta blockers, digoxin, diltiazem, or verapamil.

Warfarin Amiodarone may increase the anticoagulant effect of warfarin.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have long-term liver problems.

· You have heart problems.

· You have eye disease.

· You have a lung disorder such as asthma or bronchitis.

· You have a thyroid disorder.

· You are sensitive to iodine.

· You are taking other medicines.

Pregnancy Not recommended. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk and may affect the baby. Safety not established. Discuss with your doctor.

Infants and children Not recommended.

Over 60 Increased likelihood of adverse effects. Reduced dose may therefore be necessary.

Driving and hazardous work Avoid these activities until you have learned how amiodarone affects you because the drug can cause the eyes to be dazzled by bright light.

Alcohol No known problems.

PROLONGED USE

Prolonged use of this drug may cause a number of adverse effects on the eyes, heart, skin, nervous system, lungs, thyroid gland, and liver.

Monitoring A chest X-ray may be taken before treatment starts. Blood tests are done before treatment starts and then every 6 months to check thyroid and liver function. Regular eye examinations are required.