The UK Medicines and Healthcare products Regulatory Agency (MHRA) has published a communication to healthcare professionals (DHPC) containing information for healthcare workers who prescribe amiodarone.
The use of amiodarone has been associated with serious and potentially life-threatening adverse effects, especially affecting the lungs, liver, and thyroid gland. Healthcare professionals are reminded that patients must be under regular supervision and monitoring during treatment. Lung damage may develop slowly but progress rapidly over time. Computed tomography can help confirm a suspicion of pulmonary toxicity.
Advice for healthcare professionals
- amiodarone may cause serious adverse reactions affecting the function of the eyes, heart, lungs, liver, thyroid, skin and peripheral nervous system;
- regularly examine patients receiving long-term amiodarone therapy – some of these reactions can be life-threatening, but their onset may be delayed;
- liver and thyroid function must be checked before treatment and every 6 months; thyroid function should also be monitored for several months after discontinuation of treatment;
- although routine lung imaging is not necessary in patients taking amiodarone for a long period, inform patients of the need to seek advice if they have new or worsening respiratory symptoms, and consider using computed tomography (CT) if pulmonary toxicity is suspected.
Advice that healthcare professionals should give to patients and their caregivers
- amiodarone is used to treat serious heart conditions characterized by irregular or rapid heartbeat;
- always read the package leaflet that comes with the medicinal product, and follow the advice on other medicines to be avoided and on what to do if you have side effects;
- your doctor may perform blood tests, check lung and eye function, and measure your heart rate before and during treatment – it is important to have these tests, as they can detect abnormalities;
- stop taking amiodarone and consult your doctor or go to the hospital immediately if you develop any of the following symptoms during treatment or after you stop taking amiodarone:
- shortness of breath or worsening shortness of breath, or a cough that does not go away;
- yellowing of the skin or eyes (jaundice), feeling tired or nauseated, loss of appetite, stomach pain or high fever;
- weakness, weight loss or gain, heat or cold intolerance, hair thinning, sweating, menstrual cycle changes, swelling of the neck (goiter), nervousness, irritability, restlessness, or decreased concentration;
- your heartbeat becomes even more irregular or erratic, or becomes very slow;
- vision loss.
Amiodarone and the risk of toxicity
Amiodarone is used to treat certain types of abnormal heart rhythm, including atrial fibrillation and tachyarrhythmias. Amiodarone is generally a reserve option for situations where other treatments cannot be used or have proved unsuccessful. Treatment should be initiated in accordance with clinical recommendations and monitored under the supervision of a hospital or a specialist. Amiodarone is associated with serious adverse effects in several organ systems, including the eyes, gastrointestinal tract, nerves, skin, thyroid gland, lungs, heart and liver. Amiodarone interacts with many medicinal products, so the recommendations in the relevant section of the instruction for medical use should be strictly followed.
Amiodarone has a long plasma elimination half-life of about 50 days, which means that any adverse effects may persist for a month (or more) after treatment is discontinued.
The instruction for medical use of amiodarone contains detailed warnings and precautions. During treatment, patients must be under careful supervision.
Adverse effects of amiodarone on the lungs
Amiodarone can commonly cause inflammation of the lungs (pneumonitis). In some cases, this inflammation can progress to more serious thickening or scarring (fibrosis), which can be life-threatening. Patients should be carefully examined clinically, and a chest X-ray should be considered before starting therapy.
Symptoms of pulmonary toxicity may include shortness of breath (which may be severe and is not explained by the current cardiac condition), non-productive cough, and general deterioration of health (fatigue, weight loss, and fever). Pulmonary toxicity is usually (but not always) reversible after early discontinuation of amiodarone therapy, with or without corticosteroid therapy.
The UK regulatory agency MHRA received a report from a coroner following the death of a woman who had been receiving amiodarone for approximately 5 years and who developed pneumonia during treatment. The coroner expressed concern about the absence of a requirement to perform lung imaging when patients are prescribed amiodarone on a long-term basis.
The UK regulatory agency MHRA reviewed this issue and sought the advice of an independent expert from the Pharmacovigilance Expert Advisory Group and the Cardiovascular, Diabetes, Renal, Respiratory and Allergy Expert Advisory Group of the Commission on Human Medicines.
Updated advice on lung imaging during treatment with amiodarone
The experts who took part in the review reported that routine lung examination during treatment may expose patients to excessive radiation, cause anxiety in patients, and was unnecessary, given that deterioration in respiratory function reported by patients is usually the first indicator of the onset of pulmonary toxicity. For this reason, it is important that patients are aware of the symptoms of pulmonary toxicity to watch for, and that it can be serious and can occur at any time during treatment (or within a month after discontinuation of treatment).
The package insert for amiodarone is being updated to emphasize that respiratory symptoms may gradually worsen and may occur at any time after the start of treatment. In addition, the information for healthcare professionals is being updated to emphasize that computed tomography (CT) is more specific than X-ray and may therefore be more useful for confirming a suspected diagnosis of pulmonary toxicity.
Reminder about monitoring of thyroid function
Treatment with amiodarone can usually lead to hypothyroidism or hyperthyroidism, especially in patients with a personal history of thyroid disease, for whom the treatment is contraindicated.
Thyroid tests should be performed before starting treatment, and thereafter every 6 months and for several months after treatment discontinuation. Regular monitoring is recommended for patients whose medical history indicates an increased risk of thyroid dysfunction.
For the analysis of published information, the applicant must use the original text available at the link https://www.gov.uk/drug-safety-update/amiodarone-cordarone-x-reminder-of-risks-of-treatment-and-need-for-patient-monitoring-and-supervision
