Estradiol + Dydrogesterone Phenobarbitone
ModeratePhenobarbitone can make Estradiol + Dydrogesterone work less well. Phenobarbitone is an anticonvulsant, a medicine for fits, and it speeds up certain liver enzymes called P450 enzymes (2B6, 3A4, 3A5 and 3A7). These enzymes break down oestrogens and progestogens, so the body clears them faster and less of the hormones may reach where they are needed. Phenytoin and carbamazepine, which are also anticonvulsants, do the same. So do the anti-infectives rifampicin, rifabutin, nevirapine and efavirenz.
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.