T.D.
I would read the article on Mothering.com called "Expert Dr. Thomas Hale on Medications and Breastfeeding." It has great information on certain pain releivers and you milk. I would try and stay away from codeine, there has been recent studies questioning it while breastfeeding. Anyway the article also explains when it is best to take medication so the level in your milk is at its lowest. It has great information I think you might find helpful. Best of luck
T.