antibiotics and Plan B ?s ... Jill?
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| Mon, 05-28-2007 - 6:12pm |
You included the following quote in a response you gave another poster about Plan B ... it is a direct quote from the Plan B prescribing information, and it is something that struck me last week when I looked it up, but forgot to ask about until now.
“Theoretically, the effectiveness of low-dose progestin-only pills is reduced by hepatic enzyme inducing drugs such as the anticonvulsants phenytoin, carbamazepine, and barbiturates, and the antituberculosis drug rifampin. No significant interaction has been found with broad-spectrum antibiotics. It is not known whether the efficacy of Plan B® would be affected by these or any other medications.”
So does this mean that broad-spectrum antibiotics, which we all have advised multiple times here on the board, interact with combination BCPs only because they have an effect on the ethinyl estradiol (or ethinyl estradiol absorption)? It would seem that if the theory listed above is correct, then this would be the case.
This would, hypothetically make sense, except that when I was on Topomax for my seizures (which is NOT phenytoin, which is the anticonvulsant mentioned in the above quote), it *did* interact with my BCPs, and it caused BTB. The prescribing information for Topomax confirmed this, by stating that it interferes with the estrogenic effect of combination BCPs ... but then I always assumed BTB was a result of the progestin level or progestin absorption being affected.
Am I wrong? Do my questions even make sense? lol

Hi hon, welcome back!
Jill
Hi!!
After I wrote that, and was lying in bed last night, I had a thought: it's probably more about the RATIO of estrogen to progestin in each person's body. That seemed to make sense to me. I saw my gynecologist today and he confirmed this. I looked it up again, and Topomax affects estrogen absorption just like I thought, but the imbalance between the progestin and estrogen is what caused the BTB. Sort of backwards, but that explains it.
As for an update ...
I also got my first Gardasil shot today (HOLY $%#! it hurt like a tetanus shot)!! I always thought that you couldn't get it if you were already sexually active, but he says no, that even if you have one or more of the strains of HPV that it protects against (which we don't know if I do or not yet, i guess i'll wait on the PAP and STD results and see), you probably don't have all four, so it can still be effective, and it can even cut down on the number of warts a person gets (if she has a strain that causes warts).
He still says I'm a candidate for an IUD if I want it, but in the meantime he gave me some samples of Yaz (cheap is good, free is better!!), so I'm interested to see how that works ... 20 mg EE worked well for me with Alesse, and I had no side effects from Yasmin, so hopefully this little "combination" of the best of both worlds will help!
Yay, that's my update... Aunt Flo, you've got 10 days, hurry up and get here!
Thanks for the reply Jill!!
Thanks for the update hon!
Jill