.I've heard that Topamax does interfer with B/C but then I read a study... that said under 150mg it does not effect BC. My neurologist says low doses (under 150mg) will NOT effect Yaz but my OBGYN was wishy washy on whether or not it would. Any help? I am on 50 mg (25mg AM / 25mg pm)
Does Topamax affect the effectiveness of the birth control pill Yasmin?
- Posted:
- 19 Jul 2010 by InPain247
- Topics:
- topamax, yasmin, birth control, contraception
Responses (3)
19 Jul 2010
Yes, it may be decreased.
READ THE FOLLOWING IMPORTANT INFORMATION.
Interactions between your selected drugs
ethinyl estradiol ↔ topiramate
Applies to: Yasmin (drospirenone/ethinyl estradiol), Topamax (topiramate)
ADDITIONAL CONTRACEPTION RECOMMENDED: Efficacy of oral contraception may be decreased by concomitant use with topiramate. The mechanism of action appears to be increased metabolism of the estrogenic component of the oral contraceptive. In a pharmacokinetic study with topiramate 800 mg/day, ethinyl estradiol clearance increased by 47% (range 13% to 107%), while norethindrone was unaffected. Although this has not been reported with mestranol, the likelihood of an interaction should be considered.
19 Jul 2010
Topamax is an "enzyme inducer" which means that it speeds up the metabolism of estrogens. This can reduce the contraceptive effect of estrogen containing birth control pills such as Yasmin.
You would be wise to consider another method of contraception.
http://www.drugs.com/interactions-check.php?drug_list=2216-0,947-2536
5 Apr 2011
There is unfortunately no black and white answer to this questions because people metabolize drugs differently based on their physiology. The paper makes reference to a dosage of ethinyl estradiol: "Start with an OC pill with estrogen 50 μg at least and, if breakthrough bleeding occurs, an even higher estrogen dose may be needed." I'd send this paper to your OB/GYN and have him/her review it and then make an appointment to discuss options. The issue is having a high enough dose of hormone in your circulation. If you are more concerned about becoming pregnant, use a backup method until you come up with a better dosing regimen.
To my knowledge, topiramate does not decrease efficacy of Plan B because of the high dose of hormones in the pill.
Search for questions
Still looking for answers? Try searching for what you seek or ask your own question.
Similar questions
Could Yasmin be responsible to my slow weight gain?
I've been on Yasmin for 6 years and absolutely love it. I've noticed recently though that i've slowly put on weight. This could just ...
Am I likely to deal with side effects from Seasonique?
I have been using Ocella (Yasmin) for birth control for several years now and have had no problems with it. My gyno recommended that I switch to ...
Amitriptyline - does this medication effect birth control bill effectiveness?
The last medication I was on was topamax but I had to stop taking it due to so many side effects I was having throughout the day, and it was making ...
Loestrin 24 Fe - Here's my situation : I was on Yasmin and I was taking them all the time, stopping?
... only every 3-4 months. My doctor told me Yasmin was bad and suggested I take Loestrin 24. After my last pack of Yasmin, I had period and started ...

Thank I have already read what Drugs.com says about the interactions. I was referring to what I read here in this study April 1st at the 55th Annual Meeting of the American Academy of Neurology.
"results:
At dosages of 200 mg or less, topiramate as daily monotherapy in healthy volunteers does not have a significant interaction with oral contraceptives, researchers reported here on April 1st at the 55th Annual Meeting of the American Academy of Neurology.
results of a 2004 study:
Unlike old AEDs such as phenytoin and carbamazepine, topiramate is a mild inducer and, currently, the only interaction observed as a result of induction by topiramate is that with ethinylestradiol. Topiramate only increases the oral clearance of ethinylestradiol in an oral contraceptive at high dosages (>200 mg/day)