Bill, I've never tried the products you mention or heard of medication being recommended unless there is a contributing medical problem.   Recommendations have been pretty consistent from a number of singing workshops that I've attended:
- dairy products increase mucus build up so avoid them before singing
- ginger is good
- pineapple juice is good
- keep the fluid intake up - warm water (yuk) is more effective than icey is.

There was some surprising (to me) information given at a recent workshop - vocal chords are only about the size of a thumbnail, so it doesn't take much to interfere with them, or damage them. I'd always imagined them to be stretched along most of the throat area.