Estradiol + Dydrogesterone Phenytoin
ModeratePhenytoin can speed up how the body breaks down the hormones in this medicine, so the estradiol and dydrogesterone may not work as well. Phenytoin is one of several anticonvulsants that do this, along with phenobarbital and carbamazepine. The effect comes from phenytoin switching on liver enzymes called P450 enzymes 2B6, 3A4, 3A5 and 3A7, which clear the hormones faster.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.