Products
Amiodarone is commercially available in tablet form and as a solution for injection (Cordarone, generics). It has been approved in many countries since 1968.
Structure and properties
Amiodarone (C25H29I2NO3, Mr = 645.3 g/mol) is an iodinated benzofuran derivative derived from khellin. It is present in drugs as amiodarone hydrochloride, a white, fine, crystalline powder that is very sparingly soluble in water.
Effects
Amiodarone (ATC C01BD01) has antiarrhythmic properties. The effects are due to inhibition of phase III action potential potassium efflux in myocardial tissue. This prolongs the repolarization period and the refractory period of the action potential. Amiodarone has additional sympatholytic properties. It has a very long half-life of up to 20 to 100 days.
Indications
As a second-line agent for the treatment of various cardiac arrhythmias.
Dosage
According to the SmPC. Tablets are initially taken daily at a higher saturation dose and for maintenance therapy usually every other day or five days per week. The drug should be administered during or immediately after meals. During treatment, strong UV radiation should be avoided because the skin is more sensitive to sun.
Contraindications
Full details of precautions and interactions can be found in the Drug Information Leaflet.
Interactions
Amiodarone is metabolized by CYP3A4 and CYP2C8, and corresponding drug interactions with CYP inhibitors and CYP inducers are possible. Amiodarone is itself also a CYP and P-gp inhibitor. It has a high potential for drug-drug interactions with numerous medications.
Adverse effects
The most common potential adverse effects include microdeposition on the cornea, indigestion, a metallic taste, transaminase elevation, photosensitization, and sunburn. Amiodarone prolongs the QT interval and may itself cause cardiac arrhythmias. Numerous other side effects are possible, affecting the lungs, thyroid, and nervous system, among others.
