Side effects of amiodarone

Amiodarone has six major groups of side effects that we should know:

1- Pulmonary toxicity: We have here two main types: hypersensitivity pneumonitis and interstitial / alveolar pneumonitis. The first one matters most to us because it is acute. The therapy includes suspension of amiodarone and introduction of corticosteroids.

2 - Arrhythmias: Although class I and III drugs have been introduced as an alternative in 1985 as having markedly lower proarrhythmic activity, amiodarone is not exempt from this side effect. It can cause symptomatic bradycardia, AVB, and QT prolongation. For this reason it is formally contraindicated in sinus node dysfunctions.

3-Hepatotoxicity: Amiodarone has hepatic metabolism through cytochrome P450. Acute hepatic impairment is common and the dose should be decreased if transaminases increase 3-fold above normal in patients without prior dysfunction or fold in liver disease patients.

4 - Ocular toxicity: The microdeposition of amiodarone in the cornea is practically universal but only causes symptoms of blurring or halo in 10% of the patients. Permanent blindness may occur.

5. Thyroid toxicity: Amiodarone contains 37% iodine in its formula. It can trigger both hypo and hyperthyroidism, the latter being less frequent but more worrying about the risk of severe arrhythmias associated with thyrotoxicosis.

6. Cutaneous Toxicity (courtesy of the intensive dermatologist): Ten percent of patients on chronic amiodarone use report photosensitivity. More rare is the blue man syndrome, caused by deposits of melatonin and lipofuscin, which is reversible, although it may take time.