Skip to content
My WebMD Sign In, Sign Up

Syeda oral

Estrogens; Contraceptives/Rifamycins

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

When these two medicines are taken together, your body may process estrogen faster.

What might happen:

The effects of your birth control pills may decrease and cause breakthrough bleeding, spotting, or pregnancy. The effects of your estrogen replacement therapy may decrease. The effects of the interaction may last for several weeks after you stop taking rifampin.

What you should do about this interaction:

Talk to your healthcare professional (e.g. doctor, pharmacist) as soon as possible about using a different form of birth control. Contact your doctor if you experience breakthrough bleeding, spotting, or pregnancy.If you are taking estrogen-replacement therapy, let your doctor know if you have any menopausal symptoms.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.


1.Altschuler SL, Valenteen JW. Amenorrhea following rifampin administration during oral contraceptive use. Obstet Gynecol 1974 Nov;44(5):771-2.
2.Skolnick JL, Stoler BS, Katz DB, Anderson WH. Rifampin, oral contraceptives, and pregnancy. JAMA 1976 Sep 20;236(12):1382.
3.Back DJ, Breckenridge AM, Crawford F, MacIver M, Orme ML, Park BK, Rowe PH, Smith E. The effect of rifampicin on norethisterone pharmacokinetics. Eur J Clin Pharmacol 1979 Apr 17;15(3):193-7.
4.Joshi JV, Joshi UM, Sankolli GM, Gupta K, Rao AP, Hazari K, Sheth UK, Saxena BN. A study of interaction of a low-dose combination oral contraceptive with anti-tubercular drugs. Contraception 1980 Jun; 21(6):617-29.
5.Back DJ, Breckenridge AM, Crawford FE, Hall JM, MacIver M, Orme ML, Rowe PH, Smith E, Watts MJ. The effect of rifampicin on the pharmacokinetics of ethynylestradiol in women. Contraception 1980 Feb;21(2):135-43.
6.Gupta KC, Ali MY. Failure of oral contraceptive with rifampicin. Med J Zambia 1980 Dec-1981 Jan;15(1):23.
7.Baciewicz AM, Self TH. Rifampin drug interactions. Arch Intern Med 1984 Aug;144(8):1667-71.
8.Barnett ML. Inhibition of oral contraceptive effectiveness by concurrent antibiotic administration. A review. J Periodontol 1985 Jan;56(1):18-20.
9.Baciewicz AM. Oral contraceptive drug interactions. Ther Drug Monit 1985; 7(1):26-35.
10.Szoka PR, Edgren RA. Drug interactions with oral contraceptives: compilation and analysis of an adverse experience report database. Fertil Steril 1988 May;49(5 Suppl 2):31S-38S.
11.Nor-Q-D (norethindrone) US prescribing information. WatsonPharma March, 2005.
12.Barditch-Crovo P, Trapnell CB, Ette E, Zacur HA, Coresh J, Rocco LE, Hendrix CW, Flexner C. The effects of rifampin and rifabutin on the pharmacokinetics and pharmacodynamics of a combination oral contraceptive. Clin Pharmacol Ther 1999 Apr;65(4):428-38.
13.LeBel M, Masson E, Guilbert E, Colborn D, Paquet F, Allard S, Vallee F, Narang PK. Effects of rifabutin and rifampicin on the pharmacokinetics of ethinylestradiol and norethindrone. J Clin Pharmacol 1998 Nov; 38(11):1042-50.
14.Buss WC. Induction of hepatic drug metabolizing enzymes and pregnancy while taking oral contraceptives. J Antimicrob Chemother 1979 Jan; 5(1):4-5.
15.Gelbke HP, Gethmann U, Knuppen R. Influence of rifampicin treatment on the metabolic fate of. Horm Metab Res 1977 Sep;9(5):415-9.
16.Bolt HM, Bolt M, Kappus H. Interaction of rifampicin treatment with pharmacokinetics and metabolism of ethinyloestradiol in man. Acta Endocrinol (Copenh) 1977 May;85(1):189-197.
17.Bessot JC, Vandevenne A, Petitjean R, Burghard G. Antagonistic action of rifampicin and isoniazid on the metabolism of oral contraceptives. Nouv Presse Med 1977 Apr 30;6(18):1568.
18.Dommisse J. Letter: Oral contraceptive failure due to drug interaction. S Afr Med J 1976 May 15;50(21):796.
19.Bolt HM, Kappus H, Bolt M. Effect of rifampicin treatment on the metabolism of oestradiol and 17alpha-ethinyloestradiol by human liver microsomes. Eur J Clin Pharmacol 1975 Jun 13;8(5):301-7.
20.Priftin (rifapentine) US prescribing information. Sanofi-Aventis U.S. LLC July, 2010.

See 23 Reviews for this Drug. - OR -

Review this Treatment

Find a Drug:

by name or medical condition or shape/color (Pill Identifier)

(for example: aspirin)

(for example: diabetes)

Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Ask the pharmacist

Questions about medications? Get expert answers by video or live chat about allergies, pregnancy, sleep, and more.
See the Ask the Pharmacist event schedule.

Ask a Question

Popular Slideshows & Tools on WebMD

hands on abdomen
Can you catch one?
Woman sitting in front of UV lights
Is yours working?
woman using breath spray
What's causing yours?
womans hand on abdomen
Are you ready for baby?
MS Overview
Recognizing symptoms.
bowl of yogurt with heart shape
Eat for a healthy heart.
woman doing pushups
To help you get fit.
Colored x-ray of tooth decay
Know what to look for.
Woman sitting with child
Do you know the symptoms?
Stings, bites, burns, and more.
Allentown, PA
Are you living in one?
Thyroid exam
See how much you know.

Women's Health Newsletter

Find out what women really need.

WebMD the app

Get trusted health information. Whenever. Wherever... with your iPhone, iPad or Android.

Find Out More

IMPORTANT: About This Section and Other User-Generated Content on WebMD

The opinions expressed in WebMD User-generated content areas like communities, reviews, ratings, or blogs are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. User-generated content areas are not reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance, objectivity, or any other reason except for compliance with our Terms and Conditions. Some of these opinions may contain information about treatment or uses of drug products that have not been approved by the U.S. Food and Drug Administration. WebMD does not endorse any specific product, service, or treatment.

Do not consider WebMD User-generated content as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of something you have read on WebMD. You should always speak with your doctor before you start, stop, or change any prescribed part of your care plan or treatment. WebMD understands that reading individual, real-life experiences can be a helpful resource but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified health care provider. If you think you may have a medical emergency, call your doctor or dial 911 immediately.