Isoniazid, an anti-TB medicine, is one of the drugs that may make this tablet (Cyproterone Acetate + Ethinyl Estradiol) work less well. If you take the two together, the tablet may not protect or treat as well as expected. You may also notice more breakthrough bleeding, which means bleeding or spotting between your periods. If you are on isoniazid, tell your doctor or pharmacist before you start or continue this tablet.
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.