Venlafaxine, which is called Effexor in the USA, is an antidepressant.
It has many side effects, but no more than any other such medication. If your pain is being caused or exacerbated by stress or anxiety or depression, then taking such a drug may help. It will not dull pain, as it is not a pain medication. It may help you to manage stress in your life, which in turn might lessen the severity or frequency of your pain.
Be aware that it is a psychiatric medication and may cause various effects on your thoughts or emotions, so make sure that if you are going to try it you are prepared to deal with those if they occur. It effects everyone differently so you won't know ahead of time.
As for dosage, that is not one-size-fits-all. That has to be determined for you by the prescribing physician, who will also know whether or not it is appropriate for you to try it or if it would have a bad interaction with any other medication you take.
