Cordarone X tablets (Amiodarone)

How does it work?

Cordarone X tablets contain the active ingredient amiodarone, which is a type of medicine called an antiarrhythmic. (NB. Amiodarone tablets are also available without a brand name, ie as the generic medicine.) Amiodarone is used to control abnormal heartbeats.

The heart's pumping action is controlled by electrical signals that pass through the heart muscle. The electrical signals cause the two pairs of heart chambers (left and right atria and ventricles) to contract in a regular manner that produces the heartbeat. If the electrical activity in the heart is disturbed for any reason, irregular heartbeats (arrhythmias) of various types can result. These can seriously undermine the pumping action of the heart and result in inefficient blood circulation around the body.

Amiodarone works by slowing down the electrical impulses in the heart muscle. This helps to regulate and restore disturbances in the heart rhythm.

Amiodarone is used to treat a variety of different types of fast, abnormal heart rhythms (these are known as tachyarrhythmias). It is used for severe rhythm disorders when other treatments are not effective or cannot be used.

What is it used for?

  • Fast, abnormal heart rhythms (tachyarrhythmias), including supraventricular, nodal and ventricular tachycardias, atrial fibrillation, atrial flutter and ventricular fibrillation, when other medicines cannot be used.
  • Fast, abnormal heart rhythms (tachyarrhythmias) associated with Wolff-Parkinson-White syndrome.

How do I take it?

  • Amiodarone tablets can be taken either with or without food.
  • The dose to take and how often to take the tablets will vary from person to person and according to the type of arrhythmia you have. Amiodarone is usually taken three times a day to begin with. After a week this is then usually reduced to twice a day, then after another week to once a day. It is important to follow the instructions given by your doctor. These will also be printed on the dispensing label that your pharmacist has put on the packet of medicine.
  • If you forget to take a dose you should take it as soon as you remember, unless it is nearly time for your next dose, in which case you should skip the forgotten dose and just take the next dose as usual. Don't take a double dose to make up for a missed dose.
  • You should avoid drinking grapefruit juice and eating grapefruit while taking this medicine, as grapefruit may increase the level of this medicine in your blood and thus increase the chance of getting side effects.


  • It is recommended that you avoid drinking excessive amounts of alcohol while taking this medicine. This is because drinking alcohol while taking this medicine may increase the chance of you having problems with your liver.
  • Amiodarone can cause serious adverse reactions affecting the eyes, heart, lungs, liver, thyroid gland, skin and peripheral nervous system. (See below.) Because these reactions may be delayed, people on long-term treatment should be carefully monitored by their doctor.
  • The electrical activity in your heart should be monitored using an ECG, and the amount of potassium in your blood checked, before you start treatment with this medicine. Your heart should be monitored regularly with an ECG thoughout treatment.
  • Most medicines that control abnormal heart rhythms can also provoke them in some circumstances. For this reason, if you feel like your heart condition has got worse, or your heartbeat changes, gets faster or slower, or starts to pound, or you experience chest pain, shortness of breath or feeling faint, it is important to consult your doctor straight away.
  • Amiodarone can cause your thyroid gland to become overactive or underactive. You will need to have a blood test to check the levels of thyroid hormones in your blood (thyroid function tests) before starting treatment, every six months throughout treatment and for several months after stopping treatment with this medicine.
  • This medicine can affect your eyesight. You may notice that you get dazzled by headlights when driving at night. You should have an eye test every year while you are taking this medicine. However, if you get blurred vision or decreased vision while taking this medicine you should tell your doctor immediately so that your eyes can be checked.
  • This medicine can make your skin more sensitive to sunlight. For this reason you should avoid exposing your skin to sunlight or sunlamps while taking this medicine and for several months after stopping treatment. If exposure to sunlight cannot be avoided, use protective measures such as sun-creams or protective clothing. Your doctor can prescribe you a high factor sun-cream.
  • This medicine can sometimes cause inflammation in the lungs (pneumonitis). For this reason you should tell your doctor if you get an unexplained non-productive cough, shortness of breath, fatigue, fever or weight loss during treatment, so that your lung function can be checked. This might involve having a chest X-ray.
  • This medicine can sometimes cause liver problems. You should have a blood test to monitor your liver function (liver function test) before starting treatment and every six months during treatment. Tell your doctor if you develop unexplained itching, yellowing of the skin or whites of the eyes (jaundice), unusually dark urine, nausea and vomiting, abdominal pains, loss of appetite or flu-like symptoms while taking this medicine, as these could be signs of a liver problem.
  • This medicine can sometimes cause problems with the peripheral nerves. For this reason you should tell you doctor straight away if you start to get numb, weak, tingling or burning feelings in any part of your body.

Use with caution in

  • Elderly people.
  • Heart failure.
  • People with severe electrical conduction disturbances within the heart (high grade atrio-ventricular block, bifascicular or trifascicular block or sinus node disease). This medicine should only be used in conjunction with an artificial pacemaker in these cases.
  • People with a pacemaker or implantable cardioverter defibrillator (ICD). Your doctor will check that your device is working properly shortly after you start taking these tablets or if your dose is changed.
  • Hereditary blood disorders called porphyrias.

Not to be used in

  • People with a slow heart rate caused by the pacemaker of the heart (sinus bradycardia).
  • People with decreased heart function caused by problems with the conduction of electrical impulses leaving the pacemaker of the heart (sino-atrial heart block).
  • People taking medicines that can cause an abnormal heart rhythm seen as a 'prolonged QT interval' on an ECG (your doctor will know, but see the end of this factsheet for some examples).
  • People with an overactive or underactive thyroid gland, or a history of thyroid problems.
  • People who are allergic to iodine.
  • Pregnancy (except in exceptional circumstances).
  • Breastfeeding.
  • Cordarone X tablets contain lactose and are not suitable for people with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine could affect the thyroid gland of a developing baby. It should not be used during pregnancy unless considered essential by your doctor, as it may be harmful to the unborn baby. Ask your doctor for more information. If you think you could be pregnant while taking this medicine you should consult your doctor immediately.
  • This medicine passes into breast milk and could be harmful to a nursing infant. Women who need treatment with this medicine should not breastfeed. Seek further medical advice from your doctor.

Label warnings

  • Protect your skin from sunlight - even on a bright but cloudy day. Do not use sunbeds.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Very common (affect more than 1 in 10 people)

  • Micro-deposits in the protective outer layer of the eye (corneal microdeposits), which can cause drivers to be dazzled by headlights at night. These disappear when treatment is stopped.
  • Nausea and vomiting. This occurs with the high starting dose of the medicine and usually improves once the dose is reduced.
  • Changes in taste.
  • Increased sensitivity of the skin to light (photosensitivity - see warning section above).

Common (affect between 1 in 10 and 1 in 100 people)

  • Reversible grey/blueish tint to skin exposed to light, particularly the face. This disppears slowly after the medicine is stopped.
  • Tremor.
  • Difficulty sleeping (insomnia).
  • Nightmares.
  • Slower than normal heart beat (bradycardia).
  • Interference with functioning of the thyroid gland (overactivity or underactivity) - see warning section above.
  • Acute liver problems such as jaundice or liver failure (see warning section above).
  • Lung disorders such as inflammation or fibrosis, causing breathlessness (see warning section above).

Uncommon (affect between 1 in 100 and 1 in 1000 people)

  • New or worsening abnormal heartbeat (see warning section above).
  • Problems with the conduction of electrical signals in the heart (heart block).
  • Disorder of the peripheral nerves, causing weakness, numbness or burning/tingling sensations (peripheral neuropathy and myopathy) - see warning section above.

Very rare (affect less than 1 in 10,000 people)

  • Headache.
  • Sensation of spinning (vertigo).
  • Visual disturbances due to problems with the optic nerve (optic neuropathy or neuritis). Tell your doctor straight away if you notice any changes to your vision, for example blurred vision or decreased vision, while taking this medicine. If an eye exam shows a problem with your optic nerve you will need to stop taking this medicine, as this could otherwise to progress to blindness.
  • Chronic liver disease such as hepatitis or cirrhosis (see warning section above).
  • Moving unsteadily or staggering (tell your doctor straight away if you experience this).
  • Raised pressure inside the skull (benign intracranial hypertension). Consult your doctor immediately if you experience a severe headache, together with nausea, vomiting and visual disturbances while taking this medicine.
  • Inflammation of the epididymis which has spread to involve the testicles (epididymo-orchitis).
  • Erectile dysfunction.
  • Hair loss (alopecia).
  • Skin rashes.
  • Inflammation of blood vessels (vasculitis).
  • Decrease in the number of platelets in the blood (thrombocytopenia). Tell your doctor if you notice any unusal bruising or bleeding while taking this medicine.
  • Anaemia caused by a breakdown of red blood cells (haemolytic anaemia).
  • Decreased production of red blood cells, white blood cells and platelets by the bone marrow (aplastic anaemia).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.

It takes a long time for amiodarone to be removed from the body and interactions with other medicines are therefore still possible for several weeks or even months after stopping treatment.

There may be an increased risk of the heart beating too slowly if the following medicines are used in combination with amiodarone:

  • beta-blockers such as atenolol, propranolol
  • calcium-channel blockers such as verapamil and diltiazem
  • digoxin.

If any of the following medicines are taken with amiodarone they may increase the risk of an abnormal heart rhythm, seen on a heart monitoring trace (ECG) as a 'prolonged QT interval'. As this could increase the risk of an irregular heartbeat called Torsades de Pointes, these medicines must not be taken with amiodarone:

  • other medicines to treat abnormal heart rhythms (anti-arrhythmics), eg procainamide, quinidine, disopyramide , sotalol
  • certain antidepressants, eg maprotiline, amitriptyline, clomipramine, imipramine
  • the antihistamines astemizole, terfenadine or mizolastine
  • certain antimalarials, eg halofantrine, chloroquine, quinine, Riamet, mefloquine
  • certain antimicrobials, eg co-trimoxazole, erythromycin clarithromycin, levofloxacin, moxifloxacin, voriconazole or pentamidine
  • certain antipsychotics, eg amisulpride, thioridazine, chlorpromazine, sertindole, haloperidol, pimozide, zuclopenthixol, sulpiride
  • arsenic trioxide
  • atomoxetine
  • cisapride
  • dronedarone
  • droperidol
  • ivabradine
  • lithium
  • tolterodine.

The following medicines are not recommended for use in combination with amiodarone because they may lower the amount of potassium or magnesium in the blood, which could increase the risk of side effects on the heart:

  • corticosteroids by mouth or injection, such as prednisolone
  • diuretics such as furosemide, bendroflumethiazide, acetazolamide
  • intravenous amphotericin
  • stimulant laxatives, eg senna
  • tetracosactide
  • theophylline.

Amiodarone may increase the blood levels of the following medicines. If you are taking one of these in combination with amiodarone your doctor may need to prescribe you a lower dose and/or perform extra monitoring:

  • ciclosporin
  • colchicine
  • dabigatran
  • digoxin
  • eplerenone
  • flecainide
  • phenytoin
  • statins for lowering cholesterol, such as atorvastatin, lovastatin, simvastatin (if you are taking simvastatin as well as amiodarone your daily dose of simvastatin should not be higher than 20mg).

The anti-blood-clotting effect of anticoagulants such as warfarin or phenindione may be increased by amiodarone. For this reason, if you are taking an anticoagulant your doctor may want to check your blood-clotting time (INR) when you start or stop treatment with amiodarone, and if your amiodarone dose is altered.

Protease inhibitors for HIV infection, such as saquinavir, ritonavir, nelfinavir or fosamprenavir, may increase the amount of amiodarone in the blood and could therefore increase the chance of its side effects.

Other medicines containing the same active ingredient

Cordarone X intravenous

Amiodarone tablets and injection are also available as the generic medicine, ie without a brand name.