benzofurans and Ataxia

To assess the incidence of adverse effects associated with long-term amiodarone therapy, we reviewed the records of 217 consecutive patients who were treated for refractory arrhythmia. After an average of 11.8 months of therapy, one or more side effects occurred in 113 patients (52%). These were considered clinically significant in 42 patients (19.3%), mandating discontinuation of amiodarone in 18 (8.3%). The untoward reactions requiring discontinuation of amiodarone included thyroid dysfunction, visual disturbances, pulmonary infiltrates, ataxia, cardiac conduction abnormalities, and drug interactions. The mild side effects included corneal microdeposits, skin rashes, and gastrointestinal symptoms. There was a weak correlation between blood levels of amiodarone, the daily dose, and the cumulative dose (r = 0.23, p = 0.015). Drug levels were higher in symptomatic patients (p less than 0.03), although they received lower doses of amiodarone. While amiodarone is associated with frequent side effects, they are generally mild and do not necessitate drug discontinuation. Careful monitoring of therapy is essential to detect the potentially serious adverse reactions which are encountered in nearly 20% of patients.

Topics: Amiodarone; Arrhythmias, Cardiac; Ataxia; Benzofurans; Drug Eruptions; Drug Interactions; Female; Gastrointestinal Diseases; Humans; Male; Middle Aged; Respiratory Tract Diseases; Thyroid Diseases; Time Factors; Vision Disorders; Warfarin

Topics: Aged; Amiodarone; Ataxia; Benzofurans; Drug Interactions; Humans; Male; Myocardial Infarction; Phenytoin; Seizures

Fifty-four consecutive patients were treated with amiodarone for symptomatic ventricular tachycardia or ventricular fibrillation refractory to treatment with conventional antiarrhythmic drugs. A reversible neurologic syndrome of tremor, ataxia, and occasionally peripheral neuropathy without nystagmus, dizziness, encephalopathy, or long-tract signs developed in 54% of the patients and was the most common reason for altering or discontinuing drug therapy. Neurologic side effects improved or resolved within 2 days to 4 weeks of decreasing or discontinuing amiodarone. Frequent neurologic toxicity is a hitherto undescribed complication of amiodarone therapy. Wider recognition of this syndrome will avoid unnecessary and costly diagnostic evaluation.

Topics: Amiodarone; Ataxia; Benzofurans; Female; Humans; Male; Middle Aged; Nervous System Diseases; Tremor

Amiodarone was administered to 154 patients who had sustained, symptomatic ventricular tachycardia (VT) (n = 118) or a cardiac arrest (n = 36) and who were refractory to conventional antiarrhythmic drugs. The loading dose was 800 mg/day for 6 weeks and the maintenance dose was 600 mg/day. Sixty-nine percent of patients continued treatment with amiodarone and had no recurrence of symptomatic VT or ventricular fibrillation (VF) over a follow-up of 6 to 52 months (mean +/- standard deviation 14.2 +/- 8.2). Six percent of the patients had a nonfatal recurrence of VT and were successfully managed by continuing amiodarone at a higher dose or by the addition of a conventional antiarrhythmic drug. One or more adverse drug reactions occurred in 51% of patients. Adverse effects forced a reduction in the dose of amiodarone in 41% and discontinuation of amiodarone in 10% of patients. The most common symptomatic adverse reactions were tremor or ataxia (35%), nausea and anorexia (8%), visual halos or blurring (6%), thyroid function abnormalities (6%) and pulmonary interstitial infiltrates (5%). Although large-dose amiodarone is highly effective in the long-term treatment of VT or VF refractory to conventional antiarrhythmic drugs, it causes significant toxicity in approximately 50% of patients. However, when the dose is adjusted based on clinical response or the development of adverse effects, 75% of patients with VT or VF can be successfully managed with amiodarone.

Topics: Aged; Amiodarone; Anorexia; Ataxia; Benzofurans; Female; Heart Arrest; Humans; Lung Diseases; Male; Middle Aged; Nausea; Recurrence; Tachycardia; Thyroid Diseases; Time Factors; Tremor; Ventricular Fibrillation; Vision Disorders

Topics: Angina Pectoris; Antihypertensive Agents; Ataxia; Benzofurans; Diethylamines; Humans; Hypertension; Iodobenzenes; Male; Paresthesia; Tremor