Medications That Decrease Contraception Effectiveness

These Drugs Can Cause Pill Failure

If you're on hormonal contraception, including oral contraceptives (birth control pills)NuvaRing, or the Ortho Evra patch, you should be aware that certain medications and supplements can increase the chances of contraception failure. These medications may make hormonal birth control less effective because they increase the metabolism of hormones. This means that the hormones may be broken down too quickly by your body, thus lowering the number of hormones necessary for effective pregnancy protection.

Here are 10 medications that can lower the effectiveness of your hormonal birth control.



Antiobiotics in bed

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Despite previous beliefs that many antibiotics may interfere with the effectiveness of hormonal birth control, the only one that has been proven to cause problems is Rifadin/Rimactane (rifampin), which is used to treat tuberculosis or meningitis. Rifampin may decrease the effectiveness of NuvaRing and the patch as well. If you're on birth control pills, the patch, or NuvaRing and your doctor prescribes rifampin, you will need to use a backup method of birth control such as condoms or a diaphragm.

Your doctor may recommend a backup method when you're on other kinds of antibiotics as well, just to be safe.


Anti-HIV Medications

antiviral drug
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Efavirenz, cobicistat, and rifamin—as well as protease inhibitors including darunavir. nevirapine, nelfinavir, and ritonavir—are drugs that are used to treat human immunodeficiency virus (HIV) infection. If you are using these or another medication for the treatment of the HIV virus or AIDS, ask your healthcare provider if your specific medication will decrease the effectiveness of your birth control pill or other combination hormone contraceptives.



Barbiturate Injection
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Barbiturate medicines for producing sleep, controlling anxiety, or treating seizures (convulsions) could interfere with the effectiveness of the birth control pill. Examples of these types of medications include:

  • Felbatol (felbamate)
  • Lamictal (lamotrigine)
  • Luminal, Solfoton (phenobarbital)
  • Mysoline (primidone)

The following medications can also help with seizure (convulsion) control in certain types of epilepsy and also treat nerve-related pain. Additionally, Topamax (topiramate) may also be prescribed to help prevent migraine headaches. These medications may also lower the pill, NuvaRing, or the patch's effectiveness:

  • Trileptal (oxcarbazepine)
  • Tegretol, Carbatrol, Equetro, Epitol (carbamazepine)
  • Dilantin, Phenytek (phenytoin)
  • Topamax (topiramate)

The World Health Organization (WHO) recommends that women taking anticonvulsants not use hormonal contraception, with the exception of Depo-Provera (medroxyprogesterone acetate). Talk to your doctor about the risks.



General practitioner holding unlabeled bottle of various pills
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Some medicines prescribed for depression can theoretically alter hormone levels. Antidepressants may lower the number of hormones (estrogen and/or progestin) circulating in your body, which can compromise the pill's effectiveness. This can vary significantly from woman to woman, so a decrease in the number of circulating hormones may equal a bigger drop in the pill's effectiveness for some women than for others. On the flip slide, research has also suggested that the estrogen in the pill may decrease the effectiveness of the antidepressant.

To avoid any possible drug interactions, make sure you talk to your doctor if you're currently being treated with a specific antidepressant and you're also using a combination birth control method.


Antifungal Medications

Yeast in a petri dish
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Anti-fungal medications may also lower the effectiveness of the pill. The two types that are problematic include:

  • The oral suspension Mycostatin, Nilstat, Nystex (nystatin), which is used to treat yeast infections
  • Fulvicin, Grifulvin V, Gris-Peg, Grisactin (griseofulvin), which is used to treat fungus infections of the skin, hair, scalp, and nails, as well as ringworm, jock itch, and athlete's foot

If you are using one of these types of medications, talk to your healthcare provider about the potential of decreasing the effectiveness of the pill, ring, or patch. You may need to use a backup birth control method.


Diabetes Medications

Diabetes doing blood glucose measurement.
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Some of the medications for diabetes, including Actos (pioglitazone) and Avandia (rosiglitazone), may interact with ​birth control pills. Make sure to discuss these types of medications with your healthcare provider to see if they will affect the use of your ​oral contraceptives.


Anxiety Treatments

A woman taking medication, France
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Ask your health care provider if your specific anti-anxiety medication will decrease the effectiveness of the pill. Certain medicines used to treat anxiety, muscle spasms, or sleeping problems, such as Valium, Diastat (diazepam), or Restoril (temazepam) may potentially interfere with successful combination contraceptive use.


Pulmonary Hypertension Treatments

Chest pain in old women
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Tracleer (bosentan) is a dual endothelin receptor antagonist used to treat people with certain types of pulmonary arterial hypertension (PAH)—which is high blood pressure in the vessels of the lungs. Tracleer has been shown to decrease hormone concentrations in the bloodstream which can put you at more at risk for getting pregnant.

Birth control pills, shots, patches, and implants should not be used alone because they are not reliable when using Tracleer. You must choose and use two reliable forms of birth control at the same time.

If you have had a tubal sterilization or you have an IUD, these methods can be used alone.

Tracleer can cause serious birth defects if it's taken during pregnancy. This is such a concern that women taking this medication must have a negative pregnancy test before starting it, as well as each month during treatment with this drug.


Natural Supplements

Hypericum perforatum (St John's wort), flowers, cream, infused oil in phial, fresh and dried aerial parts, and tincture in petri dish
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In addition to prescription medications, certain supplements have been shown to lower the effectiveness of hormonal contraception. These include:

  • Soy Isoflavones: natural substances obtained from the soybean plant which claim to reduce the intensity of menopause-related hot flashes and to help maintain strong bones
  • St. John's Wort: an herb or dietary supplement that is promoted for its ability to improve mildly depressed moods

Anti-Nausea Medications

Glass of dissolving medicine with vomiting man in background
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Emend (aprepitant), which is used to prevent or treat nausea and vomiting can also interfere with oral contraceptive effectiveness. Although not a medication, excessive vomiting and/or diarrhea may also lower the effectiveness of the pill. If you are experiencing these symptoms or taking Emend, use an additional method of birth control and contact your healthcare provider for advice.

Understand How Your Contraceptive Works

If you have any questions about birth control methods or potential interactions with other medications, contact your healthcare provider. You will lower your chances of birth control failure if you have a proper and thorough understanding of how to use your contraceptive. 

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Article Sources

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