Don't quit cold turkey.
Talk to your doctor about gradually decreasing the dose.
The withdrawal symptoms are individual. I've heard some say they did just fine and others have a horrible time stopping. You won't know until you try it.
This is from the FDA med watch.
Effexor
Discontinuing Effexor (venlafaxine hydrochloride) Symptoms associated with discontinuation of Effexor, other SNRIs, and SSRIs, have beenreported (see PRECAUTIONS). Patients should be monitored for these symptoms when discontinuing treatment. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate.
Effexor
PRECAUTIONS
General Discontinuation of Treatment with Effexor Discontinuation symptoms have been systematically evaluated in patients taking venlafaxine, to include prospective analyses of clinical trials in Generalized Anxiety Disorder and retrospective surveys of trials in major depressive disorder. Abrupt discontinuation or dose reduction of venlafaxine at various doses has been found to be associated with the appearance of new symptoms, the frequency of which increased with increased dose level and with longer duration of treatment. Reported symptoms include agitation, anorexia, anxiety, confusion, coordination impaired, diarrhea, dizziness, dry mouth, dysphoric mood, fasciculation, fatigue, headaches,hypomania, insomnia, nausea, nervousness, nightmares, sensory disturbances (including shock-like electrical sensations), somnolence, sweating, tremor, vertigo, and vomiting. During marketing of Effexor, other SNRIs (Serotonin and Norepinephrine Reuptake Inhibitors),and SSRIs (Selective Serotonin Reuptake Inhibitors), there have been spontaneous reports of adverse events occurring upon discontinuation of these drugs, particularly when abrupt,including the following: dysphoric mood, irritability, agitation, dizziness, sensory disturbances(e.g. paresthesias such as electric shock sensations), anxiety, confusion, headache, lethargy,emotional lability, insomnia, hypomania, tinnitus, and seizures. While these events are generally self-limiting, there have been reports of serious discontinuation symptoms.
Patients should be monitored for these symptoms when discontinuing treatment with Effexor. Agradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate