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Amiodarone: Cancer, Thyroid & Other Side Effects

Irregular heart rhythms can be very scary. So too are the drugs that treat these arrhythmias. That’s because anti-arrhythmic medications often come with a long list of serious side effects. This is especially true of amiodarone.

Amiodarone (Cordarone, Nexterone, Pacerone) was approved by the FDA in 1985. It will come as a shock to many health professionals and patients to learn that this powerful drug was allowed on the U.S. market without the usual randomized, double-blind, placebo-controlled trials required for 99% of all medications. That is a tale of woe and intrigue that we won’t go into here.

The FDA has a great number of cautions (including a stringent “black box” warning) about amiodarone. The feds make it clear that 1) the drug has life-threatening side effects and 2) it is a difficult drug to manage. As a result, the FDA states unequivocally that amiodarone should be prescribed only for life-threatening irregular rhythms of the ventricles (“recurrent ventricular fibrillation” or “recurrent hemodynamically unstable ventricular tachycardia”) and then only when other treatments have failed. The FDA also states clearly that patients should only be started on amiodarone in a hospital setting to reduce the likelihood of a life-threatening complication. We suspect that this advice is frequently ignored.

Really Scary Amiodarone Side Effects:

• Lung toxicity is common and can be fatal; symptoms may include wheezing, difficulty breathing, fever, shortness of breath and coughing up blood. Pulmonary fibrosis is a very serious complication of amiodarone therapy.
• Liver damage, liver enzyme elevation, hepatitis
• Worsening of irregular heart rhythms, Torsades de Pointes, slow heart rate
• Thyroid disorders, hyperthyroidism, hypothyroidism, thyrotoxicosis
• Serious visual disturbances, loss of vision, optic nerve damage, blindness
• Dangerous or deadly drug interactions; amiodarone can interact with many other medications in very dangerous ways. No one should ever combine amiodarone with any other drugs without having the prescriber and pharmacist double check for incompatibility reactions.


A study from Taiwan just published in the journal Cancer (online, April 8, 2013) reveals another serious concern about amiodarone. Investigators tracked over 6,000 patients who received amiodarone between 1997 and 2008. There was a modest 12% increased risk of cancer among the patients who took this anti-arrhythmic, but that doesn’t tell the whole story. For men who took amiodarone over at least a year, the elevated risk was 46%. And at the highest dose, the risk increased to 98%. This sort of dose-response effect is worrisome because it suggests that this could be more than a random or coincidental effect.

Doctors will have a hard time making sense of this research. That’s because the FDA doesn’t quite know what to do with such information. You might be surprised to learn that many medications cause cancer in animals. For example, there are notices in the official prescribing information for medications such as omeprazole (Prilosec), which is taken for heartburn or reflux. The drug causes abnormal cell growth and stomach tumors (carcinoids) in rats. No one seems to know whether this constitutes a problem for people.

Spironolactone (Aldactazide, Aldactone) is a blood pressure medicine that is sometimes prescribed for hormonal imbalances and facial hair growth in women. It also causes tumors in rats.

Parents of children with eczema have been worried by reports that the prescription topical skin treatments, Elidel cream and Protopic ointment, are associated with lymphoma and skin cancer. The FDA has warned against using these drugs in children under two years of age. It also states that, “The long term safety of Elidel and Protopic are unknown.”

Such cautions are not reassuring; they leave patients and physicians in a quandary. The same is true for the rheumatoid arthritis injections Cimzia, Enbrel, Humira and Remicade. These very expensive bio-tech drugs have revolutionized the treatment of rheumatoid arthritis and Crohn’s disease. The FDA announced that it was investigating an association between these medications and the development of lymphoma or other cancers.

Another hugely controversial cancer connection has to do with cholesterol-lowering drugs. An article in the Journal of the American Medical Association (Jan. 3, 1996) warned that, “All members of the two most popular classes of lipid-lowering drugs (the fibrates and the statins) cause cancer in rodents, in some cases at levels of animal exposure close to those prescribed to humans.”

And just recently the FDA has reported that popular diabetes drugs such as Byetta, Januvia, Onglyza and Victoza have been linked to pancreatitis and pre-cancerous cellular changes in the pancreas.

What are we to make of the association between amiodarone and cancer? At this point it is far too preliminary to say this is a cause and effect relationship. We can say, however, that amiodarone is a challenging drug all by itself. In addition to the serious and scary side effects listed above here are some other potential problems:

Other Amiodarone Side Effects:

• Fatigue, tiredness, unsteadiness, dizziness
• Tremor, hand shaking
• Nerve tingling in extremities, burning or pain in fingers and toes
• Digestive distress, nausea, loss of appetite, vomiting, constipation,
• Deposits in the cornea of the eye
• Heart failure
• Discoloration of the skin (a blue-grey tinge)
• Rash, skin reaction (requires immediate medical attention!)
• Pancreatitis, liver damage
• Hallucinations
• Blood disorders

Anyone taking amiodarone requires very careful medical monitoring. At the first sign of any symptoms, please contact the prescriber immediately. No one should EVER stop taking amiodarone suddenly. Discontinuation might trigger life-threatening arrhythmias. Should this drug ever need to be discontinued, it should be done so only under the careful supervision of the prescribing physician and in a gradual manner.
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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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