What is the best advice for women about antibiotics and oral contraceptives? #604/15

Q:        Our patients are upset by all the different recommendations.  In writing some updated patient hand-outs, we are trying to decide the best advice to give patients when using 1) short-term broad spectrum antibiotics* and for 2) those patients on sustained antibiotics for acne or UTI prophylaxix.  Contraceptive Technology #17 suggests back-up for short courses, though most sources suggest there is little pharmacologic evidence that these antibitiocs effect efficacy of the pill.  Our patients have at times been upset by the differnet recommendations given by pharmacists, our nurses, our doctors, our dermatoligists.  What do you currently think is the best recommendation to give to patients?

*           Amoxicillin, Zithromax, Clindamycin, Macrodantin, Metronidazole, Keflex, Cipro

A:        For ONE antibiotic, rifampin, the messages is fairly clear; use a back-up contraceptive or a higher dose pill, reduce the pill-free interval or use an entirely different contraceptive. 

For other antibiotics, the message I want patients to receive is NOT clear and I think that I can assure you that as long as we are using our current COCs the messages women receive from package inserts, clinicians, women’s magazines, the National Medical Advisory Committee of Planned Parenthood and contraceptive texts will remain conflicting and frustrating. 

A take-home message you won’t like!If you are taking a broad spectrum antibiotic such as tetracycline, doxycycline, ampicillin or erythromycin, some clinicians recommend that you use a back-up contraceptive, others do not.  Some women taking these broad spectrum antibiotics use a back-up contraceptive, others do not.  The decision is up to you.

I realize that these are totally frustrating sentences.  But here is the problem:  women have successfully sued their physicians for not informing them of the possible risk of pregnancy due to broad spectrum antibiotics.

On page 305 of the 20th edition of Contraceptive Technology is more information on this question.


Broad-spectrum Antibiotics

Hormone levels in women using COCs are not lowered by the use of ampicillin, amoxicillin, Clarithromycin, metronidazole, quinolones (ciprofloxacin, Ofloxacin), doxycycline, tetracycline or fluconazole.  Virtually every COC user taking these antibiotics has hormone levels that remain well within the therapeutic range for contraceptive efficacy. 260-263,265,266  As a result, back-up methods should NOT be necessary unless the patient has problems taking her pills, e.g., if her underlying medical condition interferes with pill-taking or absorption.  Long-term use of broad-spectrum antibiotics (such as erythromycin or tetracycline for acne) is also compatible with COC use; back-up methods are not routinely needed for pregnancy prevention. 266  The only antibiotics that profoundly affect COC potency are drugs that contain hepatic enzyme inducers:  rifampin and rifapentine (Priftin), rifampin with INH, (Rifadin, Rimactane), Rifamate, Rifater (with INH and pyrazinamide) and griseofulvin (rarely used).Remember that rifampin is also widely used with other antibiotics to treat skin infections with methicillin-resistant Staphylococcus aureus (MRSA).


260: Murphy AA, Zacur HA, Charache Pm Burkman RT.  The effect of tetracycline on levels of oral contraceptives.  AM J Obstet Gynecol.  1991; 164:28-33.

263: Maggiolo F, Puricelli G, Dottorini M, Caprioli S, Bianchi W, Suter F. The effect of ciprofloxacin on oral contraceptive steroid treatments.  Drugs Exp Clin Res. 1991; 17:451-4.

265: Friedman CI, Huneke AL, Kim MH, Powell J.  The effect of ampicillin on oral contraceptive effectiveness.  Obstet Gynecol.  1980; 55:33-7.

266: Helms SE, Bredle DL, Zajic J, Jarjoura D, et al.  Oral contraceptive failure rates and oral antibiotics.  J AM Acad Dermatol.  1997; 36: 705-10

Here are the words of advice from the Planned Parenthood Federation of America:  “There is no pharmacologic evidence that the acute or chronic use of systemic antibiotics (eg. Tetracycline, ampicillin) decreases the efficiency of low-dose CODs in women who take them correctly.”

Robert A. Hatcher MD, MPH

Emeritus Professor of Gynecology and Obstetrics

Emory University School of Medicine

Atlanta, GA

June 29, 2015,July 1, 2015 

Key Words:  antibiotics, oral contraceptive pills, advice, short-term, broad-spectrum, Contraceptive Technology, back-up method, efficacy, nurses, pharmacists, doctors, dermatologists, rifampin, amoxicillin, zithromax, clindamycin, macrodantin, metronidazole, Keflex, Cipro, package inserts, Medical Advisory Committee, Planned Parenthood conflicting, frustrating, hormones levels, medical conditions, pregnancy, hepatic enzyme inducers

To learn more about the advantages and disadvantages of oral contraceptives, go to: www.managingcontraception.com.   You can order all of these books listed below from our website or by calling 404-875-5001. 


Nelson AL, Cwiak C.  Combined oral contraceptives (COCs) IN Hatcher RA, Trussell J, Nelson AL, Cates Jr., W, Kowal B, Pilicar MS. et al Contraceptive Technology 20th edition: page 305; Ardent Media Inc. 2011

Current Books:

Contraceptive Technology 20th edition

Managing Contraception 2015-2016 edition

Choices 2014 edition

choices_2013_Eng mc2013


Posted on

July 2, 2015