Do you need to use a condom while on Prednisone and birth control?

I don't know about Prednisone, but antibiotics lowers the effectiveness of Birth Control pills. It is much easier to get pregnant on the pill if you are taking antibioitics. You need to use a back up method for sex while taking antibiotics. I'm not sure about Prednisone, but you should talk to your doctor and find out what effect it has on birth control.