I had just taken the plan b pill yesterday at 5
Hi. Thanks for asking in Chat Doctor. The antibiotics like Ampicillin, Amoxicillin, Tetracycline, Azithromycin and Co-trimoxazole interfere with the function of plan B by suppressing the intestinal microflora and decreasing the duration of action of Levonorgestrel present in plan B. Since you have already taken Plan B and the above said antibiotics will reduce the efficacy of plan B you can take some other antibiotic like Cephalosporins or Azithromycin. Although Azithromycin belongs to the same group of Azithromycin it does not have any interaction with Levonorgestrel (progesterone) and only interferes with estrogen activity. Since plan B does not contain estrogen, it is safer to take Azithromycin. Also, Azithromycin is very effective in throat infection. You're treating Chat Doctor.