Can sulfa antibiotics ie. Bactrim (sulfamethoxazole and trimethoprim) affect oral birth control?

Yes. Any antibiotic can cause absorption issues with ocp's and render them ineffective. One should always ask about medications use with ocp's and the medication's effect on the ocp. If in doubt, use a back up method (comdon, foam, film etc) and talk to your pcp/gyn about it. Don't risk it! the price may be too high to pay!
Theoretical. This is talked about much more than it really happens. But to be on the safe side you can use condoms as a back up while you are on the antibiotics.
Yes. Antibiotics that have been shown to interact with birth control pills include Rifampin (brand name rifadin), and to a lesser extent, penicillin (veetids), Amoxicillin (amoxil), Ampicillin (omnipen), sulfamethoxazole/trimethoprim (septra (sulfamethoxazole and trimethoprim) or bactrim), tetracycline (sumycin), Minocycline (minocin), Metronidazole (flagyl), and Nitrofurantoin (macrobid or macrodantinhttp://www.Drugstore.Com/ask/do-anti.

Related Questions

Will bactrim (sulfamethoxazole and trimethoprim) affect my birth control pills?

No. Only antibiotics for the treatment of tuberculosis like rifampin will affect the efficacy of your birth control pills. Continue taking your pills daily and don't miss any and your effectiveness should be >95% effective. Read more...

Does Bactrim (sulfamethoxazole and trimethoprim) make the birth control tri Linyah ineffective?

No. Bactrim (sulfamethoxazole and trimethoprim) is an antibiotic, and the current thinking is that it does not decrease the effectiveness of birth control pills. The birth control pills should work with the same high level of effectiveness, with or without Bactrim (sulfamethoxazole and trimethoprim). Read more...

I took bactrim (sulfamethoxazole and trimethoprim) once literally one pill while on birth control and had unprotected sex that day what are the chances of me getting pregnant?

Low probability. If you were taking your birth control like you were instructed it is a low probability of being pregnant. Please only take antibiotics as prescribed. Short inadequate doses of antibiotics create bacterial resistance which will make it harder to treat future infections. Read more...