I was talking with a patient recently about possible antibiotics for acne but she is on oral contraceptives (OCPs).  Do you recommend back-up for OCPs when women are on antibiotics?  Is there evidence that this is not necessary?

Dr. Margaret Kini                                                                                                                                               Austin, TX

Contraceptive Pearl Answer:

Good question!  Fortunately, there is no need for back-up.  It turns out that oral contraceptives don’t interact with antibiotics (except rifampin/rifabutin).  Even broad-spectrum antibiotics don’t lower estrogen blood levels significanlty, and the pregnancy rate for women taking antibiotics doesn’t exceed the baseline pregnancy rate for oral contraceptive users.  Nevertheless, many of us know women who became pregnant during a month when they took antibiotics and birth control pills.  Why does this happen?  Researchers speculate that recall bias plays a role – as does the decreased adherence that can result from illnesses requiring treatment with antibiotics.

Helpful Resources

For more information on drug interactions and contraceptives, see:

Medical Eligibility for Initiating Contraception: Absolute and Relative Contraindications

Sources

For evidence that backs up these guidelines, see:

The World Health Organization’s Medical Eligibility Criteria for Contraceptive Use

U.S. Medical Eligibility Criteria for Contraceptive Use

Pharma-free

The Reproductive Health Access Project does not accept funding from pharmaceutical companies. We do not promote specific brands of medication or contraception. The information in the Contraceptive Pearls is unbiased, based on science alone.