A simple method to monitor serum concentrations of fluoxetine and its major metabolite for pharmacokinetic studies.

A rapid, selective and sensitive isocratic reversed-phase HPLC assay coupled with MS/MS detection for simultaneous quantification of fluoxetine and its major active metabolite in serum samples has been developed. Analytes were extracted with a simple three step liquid-liquid procedure and chromatographic separation was achieved on a C18 column. Because of its sensitivity, this HPLC/MS/MS method is suitable both for routine therapeutic drug monitoring and for pharmacokinetic studies, due to its low limits of quantification.