The effexor contains venlafaxine which is used to treat depression for those patients who are not responding to SSRI. The effexor is excreted through kidneys. The 87% of venlafaxine is excreted unchanged in 48 hours. And rest of it is in the form of metabolite. So a single dose of effexor can take 60-72 hours to be eliminated. The prolong user may require more time to secrete it.