Quote from Elle19:

I have bronchitis and was given the Zithromax Z-pak to take. I am on Estrostep FE birth control pills, the doctor and pharmacist both said it wouldn't affect my pills but the little leaflet with the medicine states that it may decrease the effectiveness of my pills. Which one do I listen to? Please help! I want to start antibotics today but not if I am going to end up pregnant. Thank you!

CERTAIN antibiotics can affect the pill. Zithromax is NOT one of those antibiotics. I highly doubt that your leaflet says "this birth control's effectiveness is decreased by azithromycin." It probably just has a generic antibiotic warning for those medications that do affect it's effectiveness.