Will clindamycin make my birth control pills ineffective?

Clindamycin & OCP's: Clindamycin is not known to interfere with oral contraceptives. The known problems are with Rifampin and possibly penicillin-type antibiotics. Still, using a back up method for now such as condoms will give additional peace of mind.

Maybe: While there is no evidence that clindamycin specifically interferes with birth control pills, I would recommend using a barrier method when taking it. Some birth control pills are activated by bacteria in the gut. Clindamycin could greatly reduce these bacteria and thereby reduce the effectiveness of your birth control pills.