Hi. This is not widely known, but it got recommended for me by a psychiatrist of some eminence. The drug is bethanechol (aka: Urecholine.) I take it two or three times a day. It does juicy up my mouth. The dosage is 25mg.

When I used to drink water, it just washed away what little saliva I had in my mouth. Sucking hard candies a lot made the roof of my mouth sore.

For dry, chapped lips, I have a piece of chewy Italian bread (toasted slightly) dipped in light tasting olive oil sprinkled with a dash of garlic salt and Italian spices. I follow that up with application of some Blistex lip cream. (Popular with professional models.)

If I do drink something, I avoid water and sip something like hot chocolate, or orange juice. A beverage with something in it, or a mug of soup or broth, stimulates saliva secretion. Alcohol only further dries the mouth. A small serving of ice cream/sorbet also helps.

I just found out that Neurontin is drying to the oral cavity, which I hadn't known. Good Luck.

Biotene gets recommended a lot, but it is pricey . . . and not much better.