I've been using Effexor XR at 300 mgs a day for many years! I first began this medication in 2002. Beginning the medication was very difficult as I experienced an increase in anxiety and panic attacks, as well as flu like symptoms. A new doctor attempted to change my Effexor to the medication called Pristiq. Within three days I was in our local emergency room due to a severe panic attack accompanied by a severe headache. I've used all the meds imaginable, but the Effexor is the only medication that has provided continual help. My previous doctor recommended that I continue to use it until menopause due to the hormonal issues that arise in women. For some, panic attacks increase during the menopausal changes.