Medications That Decrease Contraception Effectiveness

Antibiotics

Despite long-held beliefs that all antibiotics interfere with the effectiveness of hormonal birth control, the only antibiotic drug that has been proven to do so is Rifadin/Rimactane (rifampin). It's commonly used to treat tuberculosis and meningitis.

If you're on birth control pills, the patch, or NuvaRing and your healthcare provider prescribes rifampin, you will need to use a backup method of non-hormonal birth control such as condoms or a diaphragm. A typical course of tuberculosis treatment will be around 6-9 months.

Your healthcare provider may also recommend a backup method if you're taking other antibiotics, just to be safe.

Anti-HIV Medications

Drugs that are used to treat human immunodeficiency virus (HIV) infection, such as efavirenz, cobicistat, and rifampin, may interact with birth control.

A class of drugs called protease inhibitors, which includes darunavir, nevirapine, nelfinavir, and ritonavir, may also interact with hormonal contraceptives.

Anticonvulsants

Barbiturate medicines that are prescribed for treating insomnia, controlling anxiety, or treating seizures may interfere with the effectiveness of the birth control pill.

Examples of barbiturates and medications that have barbiturate actions include:

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

Other anti-epilepsy medications that may also lower the effectiveness of the pill, NuvaRing, or the patch include:

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

The World Health Organization (WHO) recommends that women taking anticonvulsants do not use hormonal contraception that has less than 30 micrograms (mcg) of estrogen.

Some women taking these medications may consider using Depo-Provera (medroxyprogesterone acetate) or an intrauterine device, such as Mirena.

Antidepressants

Some medications prescribed for treating depression may alter hormone levels, which can compromise the pill's effectiveness.

However, the effect varies significantly from one person to the next. A decrease in the number of circulating hormones may amount to a bigger drop in the pill's effectiveness for some people, but not in others.

Antifungal Medications

Anti-fungal medications may also lower the effectiveness of the pill, though the World Health Organization states that women taking hormonal contraception should be able to safely use these medications.

Antifungal medications that have been associated with contraceptive failure are:

• 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

Make sure that your healthcare provider knows if you are taking these medications. They can discuss the potential for decreased effectiveness of your current birth control and help you choose a backup method.

Diabetes Medications

Some of the medications used for treating diabetes, including Actos (pioglitazone) and Avandia (rosiglitazone), may interact with ​birth control pills. Make sure to discuss your medications with your healthcare provider to see if they will interact with your ​oral contraceptives.

Anxiety Treatments

While the research is ongoing, certain medicines used to treat anxiety, muscle spasms, and sleeping problems, such as Valium, Diastat (diazepam), or Restoril (temazepam) may potentially interfere with the effectiveness of combination contraceptives.

Pulmonary Hypertension Treatments

Tracleer (bosentan) is a dual endothelin receptor antagonist used to treat 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 risk of getting pregnant when you are using hormonal birth control.

Birth control pills, shots, patches, and implants are not reliable when using Tracleer.

If you have had a tubal sterilization or you have an IUD, you would not be at risk of becoming pregnant.

Natural Supplements

In addition to prescription medications, certain supplements have been shown to lower the effectiveness of hormonal contraception.

• Soy isoflavones: These natural substances obtained from the soybean plant have been used to reduce the intensity of menopause-related hot flashes and to help maintain strong bones.
• St. John's wort: This herbal or dietary supplement is promoted for improving mildly depressed mood and as a sleep aid.

Anti-Nausea Medications

Emend (aprepitant), which is used to prevent or treat nausea and vomiting can interfere with the effectiveness of oral contraceptives.