Atomoxetine for suppression of vasovagal syncope.

Abstract

Vasovagal syncope (VVS) is a common clinical condition with few effective medical therapies. The study aimed to evaluate the effectiveness of atomoxetine in suppressing syncope in patients with recurrent VVS. This was a retrospective, open-label, observational case series of 12 patients taking atomoxetine for suppression of recurrent vasovagal syncope. We compared syncope frequency in the 1year before atomoxetine and while subjects were taking atomoxetine. We used novel applications of the Poisson distribution to describe the results as a collection of n = 1 studies. There were 12 subjects, eight female, with a mean age 47 ± 22years and a mean Calgary Syncope Symptom Score of 2 (diagnostic of vasovagal syncope). The patients received a mean dose of atomoxetine of 66 ± 16mg (1.06 ± 0.21mg/kg). The mean follow-up period was 1.21 ± 1.01years. While taking atomoxetine, 11/12 patients appeared to improve and 7/12 had no syncope in follow-up (p = 0.0046). The annualized syncope frequency decreased from a median 5.5 (IQR 4, 6.75) syncope per year to 0 (IQR 0, 0.88) syncope per year (p = 0.002, Wilcoxon rank-sum test). According to the Poisson distribution, 7/12 subjects significantly improved with p values of < 0.0001 to 0.0235, 3/12 did not faint but had too brief follow-up times to detect significance, and 2/12 did not improve significantly. In this case series, atomoxetine was a promising oral agent for the prevention of vasovagal syncope. The Poisson distribution permits individual patient-level assessment of improvement and detects insufficient follow-up despite apparent improvement.