Viloxazine plasma concentrations and clinical response.

Eleven patients suffering from primary depressive illness were treated with 300 mg/d of viloxazine for 29 days. Blood samples were collected at weekly intervals and severity of depression assessed using the Hamilton depression rating scale. Mean plasma viloxazine level for all patients during the trial was 1.20 micrograms/ml and ranged from 0.40 to 2.70 micrograms/ml. No simple relationship between plasma concentration and amelioration score was observed at day (rs = -0.02), day 22 (rs = -0.29) or day 29 (rs = 0.09). No significant difference in plasma concentrations between responders and non-responders was observed at day 29. Side effects were not correlated with plasma concentrations.