Rapid high-performance liquid chromatographic measurement of venlafaxine and O-desmethylvenlafaxine in human plasma. Application to management of acute intoxications.

Venlafaxine, a second-generation antidepressant, acts by inhibition of the reuptake of presynaptic noradrenaline and serotonin. The main metabolite, O-desmethylvenlafaxine was found biologically active. For toxicological purpose, a rapid specific and accurate RP-HPLC assay was developed for the simultaneous determination of venlafaxine and O-desmethylvenlafaxine in human plasma. A linear response was observed over the concentration range 0.2-4 microg/ml. A good accuracy (<8%) was achieved for all quality controls, with intra-day and inter-day variation coefficient less than 10%. Finally, no interference was observed with other psychotic drugs encountered in acute poisoning. This rapid method (run time <10 min) was used to manage four voluntary intoxications involving venlafaxine.