Is this a possibility? Has anyone else had this experience. I am getting to the end of the bottles. I take 1 comtan 200 every 4 hours with carbo/levo 25-100 1.5 every 4 hours. All of a sudden it just doesn't work. It seems like then when I get a fresh supply, it works again. Can it be bad batches or can it lose it's potency with time?