Drugs That Interact With Birth Control Pills

Medically Reviewed By William C. Lloyd III, MD, FACS
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Before you take a new medication, one of the first questions to ask is this: "Are there any medications that can interact with it?" The same is true when you start taking a birth control pill, also called an oral contraceptive.

Oral contraceptive drug interactions are usually not a serious problem. However, birth control pills contain hormones. These hormones can cause problems with some medicines.

The pill can have a different effect on different medications. For instance:

  • Pain medicine. Over-the-counter painkillers may not work as well when you're also taking birth control pills.

  • Blood pressure drugs. Some medicines for high blood pressure also may not work as well for women who are taking the pill. An example is cyclopenthiazide.

  • Bronchodilators. These are medicines for asthma. Birth control pills can cause some of these drugs to have more intense effects. An example is theophylline.

  • Tranquilizers and antidepressants. The effect from some of these drugs also may be stronger because of an interaction with the pill. Examples are benzodiazepam and imipramine.

On the other hand, some medicines may cause the birth control pill to work less effectively. You could get pregnant even if on the pill. Medications that affect birth control effectiveness include antibiotics, for instance:

  • Rifampin. This is an antibiotic. It kills certain bacteria that can cause very bad infections. Rifampin is the only antibiotic proven to make the pill less effective.

  • Antibiotics. Antibiotics may cause diarrhea. This may affect your body's ability to absorb the birth control pill, which could make the pill less effective. Ask your doctor if you should use a backup birth control method if you're taking an antibiotic.

Other medications that can make the pill not work as well are drugs to treat HIV, drugs that treat serious fungal infections, and drugs to treat seizures.

Also, you should not take iron supplements or other vitamins that contain iron while you're taking birth control pills. The pill can raise your iron levels. So, you could end up with too much iron in your blood if you take the pill and supplements containing iron at the same time. Excessive iron can cause upset stomach, belly pain, and vomiting. Chronic iron overload is toxic.

What to Do

Don't stop taking any of your medications without first checking with your doctor. If you are taking a medication that may interact with birth control pills, talk to your doctor about your concerns. You may need to change to a medication that doesn't interact with birth control pills. Or, your doctor may recommend another type of birth control.

Make sure your doctor knows all of the medications you take, including the dose. This includes prescription and over-the-counter medicines, vitamins, and supplements. Make a list of them and take it to your doctor's appointment.

When you start taking a new medication, ask your doctor or pharmacist if the birth control pill or any other drugs interact with it. Also ask about any foods, herbs or supplements that may make the birth control pill less effective or affect your other medicines.

Try to have all of your prescriptions filled at the same pharmacy. Your pharmacist can help spot any drugs that may be unsafe to take together. Show your pharmacist your list of over-the-counter medications, vitamins, supplements and anything else you take.

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  1. Q&A With Dr. Cullins: Birth Control. Planned Parenthood. https://www.plannedparenthood.org/learn/ask-dr-cullins/birth-control-qa
  2. Possible Interactions With: Iron. University of Maryland Medical Center. http://umm.edu/health/medical/altmed/supplement-interaction/possible-interactions-with-iron
  3. Avoiding Drug Interactions. U.S. Food and Drug Administration. http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm096386.htm 
  4. Update on Oral Contraceptives. American Family Physician. http://www.aafp.org/afp/1999/1101/p2073.html 
  5. Iron Dietary Supplement Fact Sheet. National Institutes of Health Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Aug 8
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