Amiodarone dosage in older patients with atrial fibrillation: an open, multi-centre study

An open, multi-centre study was carried out to assess the effectiveness and tolerability of amiodarone at a lower dose than routinely used in the clinical and symptomatic treatment of older patients with atrial fibrillation who were resistant to other therapy or in whom other therapy was either poorly tolerated or contraindicated. Suitable patients for dose adjustment were selected from a dosing survey population of those aged 60 years or over who were currently receiving amiodarone at a dosage of 200 mg or more daily. Periodic 100 mg dose reductions were made at 6-weekly intervals until there were signs of exacerbation or recurrence of the arrhythmia or until a daily dose of 100 mg was reached. Evaluation of the results from 167 patients showed that 156 (94%) were stabilized on a final dose of 100 mg daily and the remaining 11 (6%) on 200 mg daily. The majority of these patients were either in sinus rhythm or atrial fibrillation with a ventricular rate less than 100 beats per min. Twenty-one patients reported 22 adverse events. The majority of adverse events were not considered serious by the investigators, while approximately half were considered as 'probably unrelated' to amiodarone treatment. Six deaths were recorded during the treatment period but none was linked to amiodarone or 'probably related' to dose reduction.