Zonisamide produces weight loss in psychotropic drug-treated psychiatric outpatients

This study examined the long-term effectiveness and tolerability of zonisamide for weight control in psychiatric outpatients using various psychotropic medications. We conducted a systematic chart review of 82 psychiatric outpatients with unwanted weight gain after the introduction of psychotropic drugs between January 2008 and September 2009 at Korea University Ansan Hospital. The primary outcome measure was the effect of zonisamide on body mass index (BMI). Additional outcome measures included safety and tolerability as assessed by the clinical global impression-severity of illness scale (CGI-S) and discontinuation rate. The mean final dose of zonisamide was 124.6 ± 53.4 mg/day and ranged from 50 mg/day to 300 mg/day. The mean BMI reduction was 0.8 ± 1.7 kg/m2 and ranged from − 2.9 kg/m2 to 4.7 kg/m2 (p < 0.001). We also observed a significant reduction in CGI-S scores from the baseline (3.8 ± 0.9) to the endpoint (3.3 ± 0.8; p < 0.001). Twelve patients (14.6%) discontinued their zonisamide treatment due to its side effects. Patients treated with zonisamide showed significant weight loss. Furthermore, its treatment was generally safe and well tolerated with few negative effects on patients' overall psychiatric symptoms. Additional research is required to confirm these results and to investigate whether patients have rebound weight gains after discontinuing zonisamide.

► We examined the long-term weight loss effect of zonisamide. ► A systematic chart review of psychiatric outpatients was conducted. ► Zonisamide showed significant weight loss in psychotropic drug-treated patients. ► The degree of weight reduction correlated with daily zonisamide dose. ► Zonisamide treatment was generally safe and well tolerated.