From the Guidelines
Amiodarone toxicity can have severe effects on the lungs, thyroid gland, liver, eyes, skin, and nerves, and requires immediate recognition and management to prevent morbidity and mortality. The effects of amiodarone toxicity can be significant, with a meta-analysis of 8522 patients showing that while amiodarone can reduce sudden deaths, it is also associated with a range of extracardiac side effects, including thyroid, skin, lung, and liver problems 1.
Key Considerations
- The frequency and severity of these side effects are related to the total amiodarone exposure, with higher doses and longer treatment durations increasing the risk of adverse effects 1.
- Pulmonary toxicity is a particularly serious complication, which can present with subacute cough and progressive dyspnea, and may require aggressive management, including withdrawal of amiodarone and provision of supportive care and corticosteroids 1.
- Regular monitoring of thyroid, liver, and pulmonary function is essential for patients on long-term therapy, with baseline tests recommended before initiating treatment and periodic follow-ups every 3-6 months.
Management of Amiodarone Toxicity
- Discontinuation of amiodarone is the primary step in managing toxicity, with supportive care and specific treatments depending on the affected organ system.
- For pulmonary toxicity, corticosteroids like prednisone 40-60mg daily with gradual tapering may be used, while for thyroid dysfunction, hyperthyroidism may require methimazole 10-30mg daily or propylthiouracil 100-150mg three times daily, and hypothyroidism requires levothyroxine supplementation.
- Liver toxicity is managed primarily through medication discontinuation and monitoring of liver enzymes, while neurological symptoms often resolve with drug cessation.
From the FDA Drug Label
OVERDOSAGE There have been cases, some fatal, of amiodarone overdose. Effects of an inadvertent overdose of amiodarone HCl injection include hypotension, cardiogenic shock, bradycardia, AV block, and hepatotoxicity.
The effects of Amiodarone toxicity include:
- Hypotension
- Cardiogenic shock
- Bradycardia
- AV block
- Hepatotoxicity These effects can be fatal in some cases. Treatment of overdose should focus on managing these symptoms, such as slowing the infusion rate or using standard therapy like vasopressor drugs, positive inotropic agents, and volume expansion 2.
From the Research
Effects of Amiodarone Toxicity
The effects of Amiodarone toxicity can be severe and varied, affecting multiple organ systems. Some of the common effects include:
- Thyroid dysfunction, including both hypothyroidism and hyperthyroidism, which can occur in a significant proportion of patients treated with Amiodarone 3
- Pulmonary toxicity, which can manifest as coughing, dyspnea, fever, and bilateral lung infiltrates, and can be life-threatening 4
- Hepatotoxicity, which can cause elevated liver enzyme levels 5
- Cardiovascular side effects, including symptomatic pulmonary side effects and neurologic side effects such as tremor and ataxia 6
- Cutaneous abnormalities and gastrointestinal side effects, including constipation 6
- Systemic inflammatory response syndrome and multiorgan failure, which can mimic sepsis 7
Organ-Specific Effects
The effects of Amiodarone toxicity can be organized by the organ system affected:
- Thyroid: Amiodarone-induced thyroid dysfunction can occur due to the high iodine content and prolonged biological half-life of the drug 3, 5
- Lungs: Pulmonary toxicity can occur, characterized by diffuse ground glass opacities, interstitial thickening, and diffuse alveolar hemorrhage 5, 4
- Liver: Hepatotoxicity can cause elevated liver enzyme levels 5
- Skin: Cutaneous abnormalities can occur, including photosensitivity and skin discoloration 6
- Gastrointestinal: Gastrointestinal side effects, including constipation, can occur 6
Risk Factors and Management
The risk of Amiodarone toxicity can be increased by certain factors, including: