Thank you for the clarification! Even with this information I would advise you that Vicodin is not a drug known to cause weight gain and neither is the withdrawal from this medication implicated in weight gain. In fact, one of the side effects of Vicodin is a loss of appetite so weight loss might be a more reasonable expectation. The only connection with weight gain would be the potential for addiction- if someone is addicted to vicodin, they are more likely to substitute one additictive behavior for another- when the medication is removed, they may unconciously turn towards food and thus suffer weight gain. As long as withdrawl is monitored and this is a concious process, this probably will not occur.
The only weight gain associated with this could be an adverse reaction to the drug; but this would not occur with stopping the drug.
I hope this better answers your question; please remember to press accept and feel free to contact me if you have anything to add.