Will keflex interfere with my birth control pills?
Patient: I have been on the birth control pills for 3 straight years now and had no problems. I started taking the medicine keflex for a rash and im taking it morning and night. I had sex without a condom tonight. Should I get plan b tomorrow or should I be ok? Doctor: Hi,Yes, Keflex can reduce the contraceptive effects of birth control pills. Keflex is an antibiotic which can reduce the absorption of birth control pills from the intestine and hence can reduce their contraceptive actions thus you are probably having a risk of getting pregnant. If you do not wish to become pregnant then you need to take Plan-B within 72 hours following the unprotected sex.Hope I have answered your query. Let me know if I can assist you further.  Regards, Dr. Mohammed Taher Ali, General & Family Physician