Amiodarone, a heart medication, has recently gotten a “black box” warning on its label per an order from the U.S. Food and Drug Administration (FDA). The medication has been the subject of several lawsuits in which plaintiffs claim serious injury from amiodarone side effects.

What is Amiodarone?

A generic medication sold under numerous brand names that include Cordarone and Nexterone, amiodarone was first developed and used in the early 1960s for the treatment of angina pectoris (non-specific chest pain related to the heart). The drug was removed from pharmacy shelves in 1967 over concerns of side effects, but re-introduced in 1974 after it was found to be effective for treating various forms of irregular heartbeat (arrhythmia), according to the book Analogue-based Drug Discovery.

Why is Amiodarone Prescribed?

Specifically, amiodarone is given to patients suffering from one or more of the following conditions:

• ventricular tachycardia (rapid heartbeat originating in the ventricles)
• ventricular fibrillation (irregular heartbeat due to a “short circuit” in the ventricles)
• wide complex tachycardia (general rapid resting heartbeat of 100 BPM or more)
• atrial fibrillation (rapid and/or irregular heartbeat originating in the atrium – an “off-label” indication)
• paroxymal supraventricular tachycardia (rapid/irregular heartbeat originating above the ventricles)

Although it has been used in cases of cardiac arrest, there is little evidence that it is effective for this purpose.

The medication is administered orally or, for more immediate therapeutic effects, injected into a vein or the bone. It works by blocking potassium and calcium pathways, which has the effect of prolonging the period of time between heartbeats.

It is not recommended for women who are pregnant or breastfeeding because of possible effects on the fetus or infant.

What Are the Side Effects?

Patients taking amiodarone often experience:

• constipation
• epididymitis (inflammation of the testicles in males)
• generalized fatigue
• nausea
• hyper or hypothyroidism
• skin discoloration and light sensitivity (after 18 months or more)
• tremors

Less frequently, patients experience serious and even life-threatening side effects that include:

• liver disease (jaundice, enlargement or inflammation)
• lung toxicity (fibrosis or scarring of the lungs)
• peripheral nerve damage

In addition, there have been reports of men taking amiodarone developing breasts (gynomastia).

In 2013, a study published in the journal Cancer indicated an elevated risk of developing malignant tumors associated with high or extended doses of amiodarone.

What Did Drug Manufacturers Know?

Although the label contains clear warnings about amiodarone side effects – which have been known for decades – the FDA has always been clear that since its second approval in 1974, it was not to be used as a first-line treatment; rather, it is prescribed when a patient either fails to respond to, or is unable to tolerate, other treatments.

Instead, at least one drug maker continued to conduct a marketing campaign aimed at convincing doctors to prescribe amiodarone first – which constitutes “off-label” marketing, something that pharmaceutical companies are prohibited by law from doing. Doctors may legally prescribe a medication for unapproved uses, but not drug companies.