Birth Control and Topamax (Topiramate)?

Hello, I was just wondering if anyone here has had experience taking birth control (Larin Fe specifically) and topamax at the same time?

I’ve been on both medications for years but did not find out that topamax can decrease the effects of birth control until about a month ago. No one ever told me.

The other night, I had a condom break and immediately after took plan b. I was on my second row of pills, so if the birth control was not working correctly, i would’ve been ovulating.

Anyone had any experience taking these two drugs together? Did it decrease the effectiveness of their birth control pills?

Thanks