Pre-mixed GI cocktail

In a hospital I worked for in Colorado, we had a container (an emptied out NS irrigation bottle) that was kept in the refrig, containing a 3-2-1 mixture of Maalox, viscous lidocaine and Donnatal elixir. We just took it out, shook it and poured 60 ml for a GI cocktail. It was mixed and brought to us by Pharmacy. Does anyone else out there do this? Where could I find articles to support the practice...or at least a copy of a policy? Thanks for your help.