I've been on birth control for over a month. My doctor prescribed me 500mg azithromycin for a day, then 250mg for 4 days because I have sinus infection. On my second day of taking the antibiotic, I had unprotected sex and was very worried because I have heard antibiotics can decrease the effectiveness of birth control. I went to Walgreens and bought the emergency contraceptive Next Choice pill, and it says you can take it within 72 hours. I took it 38 hours after the unprotected sex. I take my birth control the way it says, never missing a pill. Should I still be worried and is there a possibility that the pill didn't work because I took it 38 hours after unprotected sex?
Hi! If you were my patient, I would advise you that first of all there is no good evidence to suggest that antibiotics reduce the effectiveness of the pills. The data on the well done studies seems to indicate that the effectiveness does not change, except in the case of some unusual antibiotics such as Rifampin. Secondly, if you are taking your birth control pills appropriately, ovulation should have been prevented this cycle. Finally, the emergency contraceptive should be effective up to 120 hours after intercourse. Effectiveness decreases with time, but the chance that you are pregnant is close to zero. ANYTHING can happen, but you certainly shouldn't lie awake at night worrying! Good luck! Dr B
The Content on this Site is presented in a summary fashion, and is intended to be used for educational and entertainment purposes only. It is not intended to be and should not be interpreted as medical advice or a diagnosis of any health or fitness problem, condition or disease; or a recommendation for a specific test, doctor, care provider, procedure, treatment plan, product, or course of action. MedHelp is not a medical or healthcare provider and your use of this Site does not create a doctor / patient relationship. We disclaim all responsibility for the professional qualifications and licensing of, and services provided by, any physician or other health providers posting on or otherwise referred to on this Site and/or any Third Party Site. Never disregard the medical advice of your physician or health professional, or delay in seeking such advice, because of something you read on this Site. We offer this Site AS IS and without any warranties. By using this Site you agree to the following Terms and Conditions. If you think you may have a medical emergency, call your physician or 911 immediately.