AMDARONE

What it is

AMDARONE contains amiodarone hydrochloride as the active ingredient. The tablet formulation is available in 100 mg and 200 mg strengths as white to off-white biconvex tablets. Each 200 mg tablet of amiodarone contains approximately 75 mg organic iodine.

Approved indications

— Severe cases of tachyarrhythmias including Wolff-Parkinson-White Syndrome, supraventricular, nodal and ventricular tachyarrhythmias, atrial flutter and fibrillation, and ventricular fibrillation not responding to other therapy.

Dosing overview

Due to poor absorption and wide inter-patient variability of absorption, the initial loading and subsequent maintenance dosage schedules must be individually titrated, with particular importance placed on using the minimum effective dose. Treatment should be started with 200 mg three times daily for one week, then reduced to 200 mg twice daily for a further week, and then reduced to 200 mg daily or less if appropriate for maintenance. The scored 100 mg tablet should be used to titrate the minimum dosage required to maintain control of the arrhythmia.

Key safety warnings

Amiodarone may induce thyroid disorders, particularly in patients with personal or family history of thyroid disorders; clinical and biological monitoring with ultrasensitive TSH assay is recommended before starting treatment, during treatment, and for several months following treatment discontinuation. Hypothyroidism should be suspected if weight gain, cold intolerance, reduced activity, or excessive bradycardia occur, supported by a clear increase in serum ultrasensitive TSH; euthyroidism is usually obtained within 1 to 3 months following discontinuation of treatment. Clinical and radiological evidence of pulmonary fibrosis and/or pneumonitis has been reported; regular chest X-ray should be performed routinely in patients undergoing long-term therapy or when diagnosis is suspected. Regular monitoring of liver function tests is recommended as soon as amiodarone is started and during treatment, as hepatotoxicity has occasionally been reported. Corneal deposits develop in almost all patients and regular ophthalmological monitoring is recommended; if blurred or decreased vision occurs, complete ophthalmological examination including fundoscopy should be promptly performed, and appearance of optic neuropathy and/or optic neuritis requires amiodarone withdrawal due to the potential progression to blindness. Photosensitivity is quite common; the intensity of these reactions could be alleviated by a reduction in dosage or by application of a protective sunscreen, and patients should be instructed to avoid exposure to the sun or use protective measures during therapy.

Contraindications

Amiodarone is contraindicated in patients with known hypersensitivity to iodine or amiodarone or to any of the excipients. It is contraindicated in pregnancy and lactation. In patients in whom bradycardia or AV block is sufficient to cause syncope, patients with sick sinus syndrome, or with severe atrioventricular conduction disorders, amiodarone should only be used in conjunction with a pacemaker. Amiodarone is contraindicated in sinus bradycardia, sino-atrial heart block, and in patients with evidence or a history of thyroid dysfunction.

PBS listing

AMDARONE 200 mg tablets are listed on the PBS as a restricted item with an ex-manufacturer price of A$4.00.

Regulatory history

AMDARONE 200 mg tablets were first listed on the ARTG on 23 July 2020 under licence category RE, sponsored by Sanofi-Aventis.