Are femara (letrozole) and norethindrone used for stage 4 endometriosis?

Not very successfull. No medical treatment has ever been shown to be effective in treating stage IV endo. This stage means that there is deeply invasive endo usually between the rectum and vagina or cervix. Endo nodules are by definition deeper than 5mm, and the hormones can't penetrate well and they don't respond. You need a surgeon very experienced in complex procedures to remove the endo.
Yes. Norethindrone acetate has been used for may years to help endometriosis pain. Femara (letrozole) has recently been tried with some success but there is much less data to go by. Both may be effective but may not work in every woman. Treatment must be highly individualized.

Related Questions

Has anyone had success on femara (letrozole) and norethindrone for endometriosis?

Sometimes. Femara (letrozole) is an aromatase inhibitor that prevents endo from producing its own estrogen. It will only work for endo in women who have been castrated. Norethindrone is a synthetic progestin that suppresses endo. Both can give some pain relief, and Norethindrone usually has much fewer side effects. The ais cause severe menopausal symptoms and most young women can't tolerate them. Read more...
Hormonal treatment. Femara (letrozole) inhibits the formation of estrogen within the endometriosis tissue. Aromatase inhibitors, formerly used to treat some breast cancer, have been successful in the treatment of endometriosis. Norethindrone, a Progesterone is also successful in some cases. Read more...