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Medications that Lower Hormonal Contraception Effectiveness

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Updated May 22, 2014

Certain medications, antibiotics, and supplements can increase the chances of oral contraceptive (birth control pill), NuvaRing and Ortho Evra patch failure. These drugs and medications may cause interactions when used with some hormonal contraceptives. These drugs may also make hormonal birth control less effective because they increase the metabolism of hormones. This means that the hormones may be broken down by too quickly by the body, thus lowering the amount of hormones necessary for effective pregnancy protection.

If you have any questions about birth control methods, please contact your healthcare provider. You will lower your chances for birth control failure if you have a proper and thorough understanding of how to use your contraceptive.

1. Antibiotics

Some antibiotics that are used to treat infections may cause the Pill to be less effective. The following antibiotics/antibacterial agents may interfere with pill use:

  • Rifadin, Rimactane, Rifater, Rifamate, IsonaRif (rifampin): used to treat tuberculosis or meningitis.
  • Mycobutin (rifabutin): used to treat mycobacterium avium complex.
  • Priftin (rifapentine): used to treat TB.

Some types of antibiotics that are used to treat bacterial infections, like pneumonia and other respiratory tract infections, acne, infections of skin, urinary tract infections, and certain sexually transmitted infections could potentially lower the effectiveness of hormonal birth control. These medications can include:

  • Sumycin, Achromycin V, Panmycin, Diabecline, Acnecycline, Dyabetex, Tetra-abc (tetracycline):
  • Bactrim (sulfamethoxazole/trimethoprim)
  • Solodyn, Minocin, Dynacin, Arestin (minocycline)
  • Flagyl (metronidazole)
  • Macrobid, Macrodantin (nitrofurantoin)

Some types of penicillin; Moxatag, DisperMox (amoxicillin); Polycillin, Principen (ampicillin) and Kelfin (cephalosporin) may also decrease pill effectiveness.

It is impossible to determine if taking an antibiotic will interfere with pill use (since each person's body responds differently), so it is wise to use a back-up method while on antibiotic medication as a precaution. If your doctor wants to prescribe an antibiotic, it is important that you let your doctor know that you are using hormonal contraception.

2. Anti-HIV Protease Inhibitors

Norvir (ritonavir) is an antiviral drug that is used to treat human immunodeficiency virus (HIV) infection. If you are using this 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 the Pill and other combination hormone contraceptives.

3. Anti-Seizure Medications

Barbiturate medicines for producing sleep, controlling anxiety or treating seizures (convulsions) could interfere with the effectiveness of the Pill. Examples of these types of medications would be:

  • 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 pill, NuvaRing, or the patch's effectiveness:
  • Trileptal (oxcarbazepine)
  • Tegretol, Carbatrol, Equetro, Epitol (carbamazepine)
  • Dilantin, Phenytek (phenytoin)
  • Topamax

Please inquire with your healthcare provider if you are use the pill and are taking any of these medications.

4. Antidepressants

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

Research indicates that the SSRI (selective serotonin reuptake inhibitor) Serzone (nefazodone) may lower the pill's effectiveness.

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

5. Anti-Fungal Medication

Anti-fungal medications may also lower the effectiveness of the pill. Some of these include:

  • The oral suspension Mycostatin, Nilstat, Nystex (nystatin): used to treat yeast infections.
  • Fulvicin, Grifulvin V, Gris-Peg, Grisactin (griseofulvin): 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, ask your healthcare provider if your specific medication will decrease the effectiveness of the pill, ring, or patch.

6. Diabetes Medication

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.

7. Anxiety Treatments

Ask your healthcare 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.

8. Pulmonary Hypertension Treatments

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. Another concern is that Tracleer can cause serious birth defects if 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.

According to the manufacturer, when using Tracleer, females who are able to get pregnant must use two forms of birth control due to the possibility of birth defects.

  • 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 have an IUD, these methods can be used alone. 

9. Natural Supplements

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 being promoted for its ability to improve mildly depressed moods.

10. Vomiting and Diarrhea

Although not a medication, excessive vomiting and/or diarrhea may also lower the effectiveness of the pill.

Additionally, the medication, Emend (aprepitant), which is used to prevent or treat nausea and vomiting can also interfere with the oral contraceptive effectiveness. If you are experiencing these symptoms or taking this medication, use an additional method of birth control and contact your healthcare provider for advice.

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