Risk-Benefit Assessment of Amiodarone in the Treatment of Cardiac Arrhythmias

Abstract

Cardiac arrhythmias are a cause of significant morbidity and mortality in patients with cardiac disease, and thus represent a major management problem. The recognition that antiarrhythmic drugs have the potential to aggravate as well as to attenuate arrhythmias has prompted clinicians to reconsider treatment strategies and weight the benefits of treatment against the risks. In this context, amiodarone has emerged as an effective antiarrhythmic agent and when used at the lowest effective dose has an acceptable side effect profile. This review focuses on the current clinical usage of amiodarone in a broad variety of cardiac arrhythmias, and addresses the risk-benefits arising from its use. It further discusses the current position of amiodarone in the management of sudden cardiac death.

Comparative Haemodynamic Effects of Verapamil, Flecainide, Amiodarone and Sotalol in the Conscious Rabbit

“…The mean concentration of amiodarone measured at 3 rnin after a 5 mg/ kg i.v. bolus injection was 4.1 f 1.5 mg/ L which is above the recommended human therapeutic range of 1-2.5 mg/ L (Counihan & McKenna 1990), but was similar to values obtained in man with the same weight adjusted i.v. dose (Andreasen et al 1981).…”

“…While this in part relates to concerns of lethal pro-arrhythmia associated with flecainide and other class lc drugs reported by the Cardiac Arrhythmia Suppression Trial (CAST) investigators (Echt et al 199 l), clinical experience with amiodarone and sotalol has been favourable, even in patients with severe left ventricular dysfunction (Amiodarone vs Sotalol Study Group 1989). While pro-arrhythmia may still occur with either of these two drugs, the incidence appears in general, to be less than that seen with class 1 antiarrhythmic drugs (Counihan & McKenna 1990).…”

Adherence to the NASPE Guideline for Amiodarone Monitoring at a Medical University

“…This study demonstrated that a computerized tool in addition to collaboration among health care professionals was effective in increasing the percentage of patients receiving laboratory monitoring at initiation of therapy. 16 Multidisciplinary clinics have also been shown to have a higher adherence rate to amiodarone monitoring guidelines. 12 A specialized amiodarone clinic at the University of Illinois at Chicago provided care to its patients according to accepted monitoring guidelines, and increased adherence to guidelines from 23% prior to referral to 90% after clinic enrollment.…”

“…If patients are not adequately monitored, the risks of amiodarone therapy may outweigh its beneficial antiarrhythmic effects. 15,16 Unfortunately, there are no additional outcome data associated with amiodarone monitoring guideline adherence. Yet, based on the frequency and seriousness of the adverse effects associated with the use of amiodarone, it seems likely that early detection through the recommended laboratory and radiographic assessments would result in improved patient outcomes.…”

Thyroid Disease in Older Patients

“…121 ] Hypothyroidism and hyperthyroidism may also occur with amiodarone, the former being found in I to 20% of elderly people taking this drug. [22,23] Those with an autoimmune thyroid disease (as evidenced by thyroid antibodies) appear to be at highest risk of hypo thyroidism. [24] Overt hyperthyroidism occurs in 1 to 5% of patients, often presenting with bodyweight loss and proximal myopathy.…”