Best thing to do is call your Dr.and tell him that you can not take the drug he perscribed and ask him if he can inject your knee with a little depo medrol. This is a form of a cortico steroid, but will not interfear with your cycle or your health. I am not sure of the drug that you have mentioned. This is not one of the drugs we keep samples of in our office. If you do want to continue with an oral medication, I would strongly reccomend 25mg of Vioxx a day. This is what I take when I have flair ups in my shoulder, and it usually takes care of it in about 2-3 days. Let me know if you need anything else.