Frequency, characteristics, and risk factors for amiodarone neurotoxicity.
OBJECTIVE
To assess the incidence, severity, and spectrum of neurologic toxic effects associated with administration of amiodarone hydrochloride.


METHODS
Retrospective medical record analysis of cardiac patients treated with amiodarone between January 1, 1996, and July 31, 2008.


METHODS
Residents of Olmsted County, Minnesota, treated at the Mayo Clinic.


METHODS
The Mayo Clinic medical records of all adult Olmsted County residents prescribed amiodarone between January 1, 1996, and July 31, 2008, were reviewed and all possible neurologic adverse effects that might be attributable to amiodarone were tabulated.


METHODS
Risk factors and clinical characteristics of patients developing neurologic problems were compared with those who did not.


RESULTS
Over the 151 months of analysis, 707 patients were treated with amiodarone. Among these patients, the cumulative incidence of likely amiodarone neurotoxic effects was 2.8%; 1.6% of all amiodarone-treated patients were referred to Neurology for a neurotoxic reaction. Neurologic problems included tremor, gait ataxia, peripheral neuropathy, and cognitive impairment. The primary risk factor for amiodarone neurotoxic effects was duration of treatment, not age, drug dose, sex, or indication for therapy. Where this could be assessed, the adverse effects were usually but not always reversible.


CONCLUSIONS
Amiodarone infrequently causes clinically significant neurologic toxic effects. Substantially higher estimates of neurotoxic effects in the early amiodarone era may be related to a much higher daily dose.
Orr
Carolyn F
CF
Department of Neurology, Mayo College of Medicine, Rochester, Minnesota 55905, USA.
Ahlskog
J Eric
JE
D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000009:adverse effects*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects*; D005260:Female; D006331:Heart Diseases / Q000188:drug therapy; D006801:Humans; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data; D009460:Neurologic Examination / Q000379:methods; D020258:Neurotoxicity Syndromes / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors
D000889:Anti-Arrhythmia Agents; D000638:Amiodarone