I am on birth control. i had my last day of antibiotics today. i'm on the first week of bc pills. how long until i don't have to use alternate bc?

B.C. stays effective: The current thinking is that except for rifampin, other commonly-used antibiotics do not alter the effectiveness of birth control pills. This is likely presuming a person is not sick with vomiting or diarrhea, or some other condition that decreases the absorption of a swallowed pill. One can look up: http://www.ncbi.nlm.nih.gov/pubmed/12063491