I am not on birth control now but i start next month. i am getting on antibiotics. how long until it is out of my system for birth control to work?

Up to couple of days: If you finish your antibiotic treatment before you start taking birth control pills, will be no interference. If you take antibiotics in the future, just count for not being protected until the following period and add other contraceptive methods.

More Important - BC: BC - birth control, will be important for you to use now, such as condoms and spermicide suppositories, until you complete first 2 weeks of your pills. Anytime you are on antibiotics, condoms are recommended since pill failure can occur. Continue taking your pills and use the condoms as long as you are taking the antibiotics. If they are long acting, then you may choose to extend condom use 2 days

Pretty quick: i would think that 48 hours after completing antibiotics it would be ok to start BCP without being concerned

Start on time: Start the birth control. You have to protect against pregnancy for a time after starting birth control anyway. Best to start birth control on time.

Depends: If you are on pill and start abx as a general rule if you finish your antibiotic in the first or second week of your pill pack, you need additional protection until you finish that current pack. If you finish your abx in the 3rd or 4th week of your pill pack, you need additional protection until you finish the 2nd week of your next pill pack. Hope this helps. Dr R