Can half a milligram of Klonopin interfere with the effectiveness of "the pill"?

I googled it and pretty much all of the sites I’ve seen have said that even a dose as small as 0.5 mg can make the birth control pill ineffective, and if your girlfriend gets pregnant while she’s still taking Klonopin, it can potentially harm the baby. I’d immediately start using another birth control method if I were you. However, since the internet really can’t be trusted all that much, she might want to give her doctor a call and ask about it.

Have her call her gynecologist as soon as possible. Whenever you are on a medicine and you start taking another, you should tell the physician prescribing the new medicine as well as the physician who prescribed the one you’re already on and ask about interactions, particularly involving birth control. Needless to say, you should definitely use an additional form of birth control to play it safe.

This is the closest thing I can find in the scientific literature on the topic:

There are no interactions between the combined oral contraceptive pill, progesterone-only pill, medroxyprogesterone injections or levonorgestrel implants and . . . the benzodiazepines. (Klonopin is a benzodiazepine.)
from: http://www.cnsdrugs.adisonline.com/pt/re/cns/abstract.00023210-200216040-00005.htm;jsessionid=Jsnfg8JnWwvkbM9WkG1lBrFvh2rJKR34FXJK7z169GQ2QTJ8TdJR!751744069!181195628!8091!-1

Double check with your doc anyway, but sounds okay to me.

Edit: But I have no idea what I’m talking about, so don’t listen to me. Call your doctor.

@nikipedia I sense a degree of hesitance to give out medical advice from a layperson. I feel the same way. The powers that be should include a medical waiver in the membership process so we would feel free to diagnose. You get a great answer. I just hope we don’t get sued when little babypedia shows up.

Didn’t the doctor who prescribed the klonopin check on what other meds she was taking?
That is routine practice (IANAD)?

I’ve personally taken benzos along with birth control, and never had an issue. But I was under the care of a doctor who asked me all the medications I was on.
You can always go to or call any pharmacy, and ask a pharmacist.
It is very important that she knows this, because Klonopin is a category D.

You should also look at the information pamphlet that accompanies the pack of pills. It should have a list of medications that could have potentially dangerous interactions and medications that will be rendered ineffective or will render the pill ineffective.