Well if it's copious amounts of phlegm, then it will be hard not to swallow it. I think you could try and do the best you can do to keep it coming up and out. I think that cayenne is amazing, but it also has effects on the blood.
I use Sinus Busters which is a cayenne based nasal spray. They also have a throat spray. Maybe you should google it!! The nasal spray hurts for a few seconds....like YEOWWWW.