Relationship between antidepressant response and plasma concentrations of fluoxetine and norfluoxetine

Abstract

The relationship between plasma concentration, clinical outcome and side-effects was examined in 23 patients with major depressive disorder (DSM-I1I-R) treated with fluoxetine. All patients received a fixed dose of 20 mg for 6 weeks. Good response was observed in 57% of patients, while 30% of patients had moderate responses after 6 weeks of treatment. Fluoxetine and norfluoxetine plasma concentrations were not significantly influenced by age and sex. At 6 weeks, plasma fluoxetine concentrations were not significantly different between responders and non-responders to treatment (82.2 ± 59.6 p.g/1 vs. 84.7 ± 6.7 pg/l) or those with or without side-effects (74.6 ± 28.7 p.g/1 vs. 87.0 ± 66.6 p.g..