Hi.
Glad you're investigating birth control options. Yes, some antiobiotics may affect oral contraceptives. For further information, ask your question in the gynecology expert forum at:
http://www.medhelp.org/forums/show/103
Antibiotics do not stop birth control pills from working, but they do decrease their effectiveness. Birth control pills do not prevent 100% of pregnancies even if taken correctly, even for someone not on antibiotics.
However some medications can REDUCE the effectiveness of contraceptive pills, which will INCREASE your risk of pregnancy. But it is important to understand that there are no contraceptive methods (except abstinence) that can prevent 100% of pregnancies.
Antibiotics have no effect on condoms, and for even greater protection using a condom correctly during all intercourse while also on birth control pills (which may be less effective while on antibiotics) would offer extremely effective birth control...But still nothing short of complete abstinence is 100%
Also, you might look into getting a prescription for topical antibiotic treatment instead of the oral..but the oral antibiotics are probably more effective.