There is some confusion out there when it comes to mixing estrogen-containing birth control with certain medications. Many women want to know if they decrease the effectiveness of the birth control and increase their chance of getting pregnant.
The fact is there are very few medications that have been proven to do that. However, certain medications, antibiotics, and supplements can cause the birth control pill, ring and patch to fail. These may stimulate the liver's ability to metabolize contraceptive chemicals, and may indeed lower the pill's effectiveness.
In Women’s Health Magazine, Kent Holtorf, M.D., and medical director of Holtorf Medical Group, listed some but not all the drugs that may interfere with birth control. Here’s a “watch list.”
When it comes to antibiotics, watch for rifampin. It is used to treat tuberculosis and bacterial infections. Tetracycline is often used to treat acne. Also watch for ampicillin and amoxicillin, which treat bacterial infections such as urinary tract infections. Common antibiotics do not cause a problem, but for those who want extra reassurance, consider using another form of birth control, like a condom, while on the antibiotics.
Watch for these anti-seizure and migraine medications. Phenobarbital treats seizures and sometimes insomnia. Carbamazepine is used for epilepsy, bipolar disorder, and sometimes ADHD and schizophrenia. And topamax, which treats migraines and epilepsy
Keep an eye out for anti-fungal medications like griseofulvin, used for skin infections and nystatin which treats yeast infections.
Anti-anxiety medications like benzodiazepine and antidepressants such as Prozac, Celexa and Zoloft may interfere with estrogen-containing birth control.
HIV medications can affect the body’s hormone levels, which can alter the effectiveness of the pill.
Respiratory medications such as theophylline, used to treat respiratory diseases like COPD or asthma and diabetic medications like Avandia can affect certain birth control.
Certain herbal supplements and foods can also interfere with the pill. These include grapefruit juice, St. John’s wort and some soy products.