Taking Plan B with birth control

Patient: I am on falmina birth control and recently the last week have been taking an antibiotic, amoxicillin, for a gum infection. The day of taking my last antibiotic I had sex and the condom broke and he did cum inside me. Knowing that antibiotics affect birth control I took the morning after pill, plan b, 6 hours later. Will my chances of becoming pregnant be slim? Should I be worried?

Doctor: Thank you for your question. Plan B is an emergency contraceptive medication that is comprised of Levonorgestrel. This functions to prevent fertilization by inhibiting ovulation. When taking within 12 hours of intercourse it is usually 95% effective at preventing pregnancy. Since you were on birth control already, it is likely that you are not ovulating anyways. We suggest that you need not worry about becoming pregnant, and wait until your period to consider any further action. If you are late, or it is missed, please see your doctor to conduct a pregnancy test.Thank you for choosing askthedoctor.com