Sotalol proarrhythmia: a report of five cases and an audit of the use of a sotalol in a teaching hospital.

Background: Polymorphic ventricular tachycardia is an uncommon complication of sotalol use.

Aims: The aims of this study were: (1) to report five cases of sotalol proarrhythmia and (2) to audit the use of sotalol in a teaching hospital population.

Methods: Five patients with sotalol proarrhythmia (defined as new ventricular arrhythmias associated with sotalol administration) were identified over an 18 month period. Sotalol use for patients admitted to the John Hunter Hospital was audited over a six month period with 85 patients (55 males) identified from the pharmacy database. Medical records were reviewed and the details of treatment including sotalol dose and indication determined. Creatinine clearance was estimated by the Cockcroft and Gault regression equation.

Results: The audit indicated that sotalol was prescribed predominantly for management of atrial arrhythmias (80%). Paroxysmal atrial fibrillation was the most common indication (71%). Although female patients were older (72 +/- 13 vs 62 +/- 15 years, p < 0.001) and had a lower creatinine clearance (55 +/- = 24 vs 82 +/- = 32 mg/minute, p < 0.001) than male patients, they were prescribed similar doses of sotalol (206 +/- 112 vs 193 +/- 93 mg/day). The ratio of sotalol dose to creatinine clearance was higher in female patients (4.0 +/- 2.6 vs 2.16 +/- 1.5, p < 0.01). The five patients with proarrhythmia (torsades de pointes in four patients and polymorphic ventricular tachycardia in one patient) were all female. Daily sotalol dose (odds ratio for each 160 mg tablet 4.9 [95% confidence interval 1.5-16] and female gender (p < 0.01) were significant risk factors for proarrhythmia.

Conclusion: Sotalol dose was not appropriately adjusted for creatinine clearance which is age and gender dependent. Female patients have an increased risk of proarrhythmia and should receive lower doses of sotalol.