The atropine may very well not present a problem, and there is the possibility of atropine content reduction of soluble tablets by placing them on an ink blotter with a drop of water on top, then preparing a shot from the remainder of the pill. Canada and many other countries prohibit manufacturers from including secondary active ingredients for the above reason; their Talwin PX does not contain naloxone. However, as a narcotic agonist–antagonist, pentazocine and its relatives can cause withdrawal in those physically dependent upon narcotics.