Saliva Substitutes

My mother was diagnosed 10 years ago, and like many others, the majority of her salivary glands do not function. She has tried a saliva substitute (I'm afraid I don't know which, but it came in a spray bottle), but gave up on it because it was causing her functioning glands to unload any fluids they had, and causing all the glands pain - as if they were being wringed dry. I am on a mission to find her a working substitute.
There has to be a treatment that really works (besides milk, which she depends on to keep her mouth coated). So, having read over past discussions, I have found your suggestions: Entertainers Secret, cool mist vaporizer, Oral Balance, and, of course, Salagen. Those of you who have the same problem, I'm sure you've tried your share of substitutes including these. In your opinion, which works best? And, are there any other secrets out there?
BTW: I just read online that taking anticholinergics, antihistimines, or some antihypertensive agents cause a reduction in salivary flow. Don't know if that will help anyone out there.
Email me if you're up to it (kmswann@mtholyoke.edu), but I'll be checking here as well for your wisdom.
Thanks