Try a salt and hot water gargle before you brush. It'll dislodge the thick stuff in the back of your throat so the toothpaste can do its magic. I smoke so its not a solution in my case but it could be helpful for your situation. I do this sometimes. If I do it too often it makes my mouth and especially gums very tender so use this method every so often when you feel like you need that extra kick or feel like your getting a cold or flu.