The single-dose pharmacokinetics of amiodarone have been studied in volunteer subjects given 400 mg doses by the intravenous and oral routes. The data show the compound to have a very large volume of distribution, a low total clearance, and a long and variable terminal elimination half-life. In patients the terminal elimination half-life was on the order of 40 days, with a more rapid phase of elimination in the first few days following the withdrawal of therapy. The terminal elimination half-life of desethylamiodarone was longer than that of the parent compound. High concentrations of amiodarone and its desethyl metabolite were found in tissue samples, with fat forming a potentially large tissue reservoir of the drug.

Harris et al. 40. Narula OS, Samet P, Javier RP: Significance of the sinus-node recovery time. SUMMARY Although amiodarone is an effective antiarrhythmic agent, long-term therapy may be associated with unwanted effects. We report our experience in 140 patients treated over 5 years. Important effects were seen particularly in the thyroid gland, liver, lung and skin. Some of these effects are dose-dependent and others may be related to the chemical structure and metabolism of amiodarone. Corneal microdeposits were always found when sought, but did not cause impairment of visual acuity.AMIODARONE has been available in Europe for approximately 20 years for the management of angina pectoris,' but only in the past decade have its unique antiarrhythmic properties been recognized.2 It is effective in the management of refractory ventricular arrhythmias, including those associated with ischemic heart disease and the cardiomyopathies.3 4 It is particularly useful in the management of chronic atrial arrhythmias refractory to conventional drugs, with an impressive conversion rate of chronic atrial fibrillation to sinus rhythm.4 Amiodarone is especially effective in suppressing or modifying paroxysmal atrial arrhythmias, including those associated with the Wolff-Parkinson-White syndrome,5 in which sudden death from rapidly conducted atrial fibrillation is a risk.6With the more widespread use of amiodarone, several side effects have been identified. In the majority of

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A new method has been used to measure tissue levels of amiodarone and its major metabolite desethylamiodarone. Amiodarone-pigmented skin has a drug and metabolite concentration ten times that of non-pigmented skin. Iodine-rich amiodarone and its metabolite have been detected in secondary lysosomes by energy dispersive analysis of X-rays. Amiodarone induces a phototoxic reaction with an action spectrum in both the UV-B and UV-A wavelengths.