According to DANDR, ANY medication, hormonal or otherwise can interfere. He also says that our metabolisms can slow as early as our late 30's-wretched tho't! It is my personal opinion that you can probably overcome this by strictly foloowing the plan--with lots of water and a regular exercise routine, of course.

Try it and see. If you have a supportive doctor, ask about it. Good luck, keep us posted on your progress!