Effexor Questions › Category: Tox Screens › Effexor 0 Vote Up Vote Down Katie asked 6 years ago Can Effexor (venlafaxine) cause a false positive for tramadol? I read that somewhere but I wasn’t sure about the validity. Thank you! 1 Answers 0 Vote Up Vote Down answered 6 years ago No, venlafaxine will not cause a false positive for tramadol.
Katie