Amiodarone-Induced Neuropathies and Related Neurotoxicities

Abstract

Objective: To report the frequency and symptomatic characteristics of amiodarone-induced neuropathies and related neurotoxicities. Data Sources: Literature retrieval was accessed through MEDLINE and PubMed (1950–July 2010), using the terms amiodarone, neuropathy, and neurotoxicity. In addition, reference citations from publications identified were reviewed. Study Selection and Data Extraction: All articles published in English retrieved from the data sources were assessed. Case reports, randomized trials, and retrospective medical record analyses were included in the review. Data Synthesis: The frequency and characteristics of amiodarone-induced neurologic disturbances are not well established. We reviewed 7 case reports, 8 randomized trials, and 1 retrospective record analysis. Neurologic adverse reactions associated with amiodarone therapy consistently presented as tremor, gait ataxia, peripheral neuropathy, or a combination. Amiodarone dose and duration of exposure ranged from 200 mg/day to 1200 mg/day and 21/2 months to 20 years, respectively, across case reports. Similarly, clinical trials and retrospective analysis demonstrated widely varying rates of neurotoxicity after amiodarone exposure, from 1.6% to 54%. A dose- or duration-dependent nature of amiodarone exposure and its associated neurotoxicity is difficult to substantiate, based on current literature. Nonetheless, the nature of its clinical presentation and mechanism of pathogenesis is better understood. Conclusions: A dose- or duration-dependant rise in the frequency of amiodarone-induced neurologic disturbances has not been established, due to variances in dose and duration exposure, differing study definitions of neurotoxicity, and inconsistent criteria for reporting a drug event, across relevant literature.