Precautions and Contraindications
Norethindrone shares the toxic potentials of progestins, and the usual precautions of progestin therapy should be observed. Because oral contraceptive combinations contain progestins, the precautions associated with oral contraceptives should generally be considered in patients receiving progestins. Prior to initiation of therapy with norethindrone in women, a physical examination should be performed, including special attention to the breasts and pelvic organs and a Papanicolaou test (Pap smear). Women receiving norethindrone should be given a copy of the patient labeling for the drug.
Norethindrone should be used with caution, and only with careful monitoring, in patients with conditions that might be aggravated by fluid retention (e.g., asthma, seizure disorders, migraine, or cardiac or renal dysfunction). The drug should also be used with caution in patients with a history of mental depression; norethindrone should be discontinued if depression recurs to a serious degree during therapy with the drug.
When breakthrough bleeding or irregular vaginal bleeding occurs during norethindrone therapy, nonfunctional causes should be considered. Adequate diagnostic procedures should be performed in patients with undiagnosed vaginal bleeding.
The manufacturers caution that the effect of long-term norethindrone therapy on pituitary, ovarian, adrenal, hepatic, or uterine function has not been determined. Diabetic patients should be carefully monitored during norethindrone therapy, since decreased glucose tolerance has been observed in women receiving estrogen-progestin combinations. Norethindrone may mask the onset of climacteric in women.
The clinician and the patient using norethindrone should be alert to the earliest signs and symptoms of thromboembolic and thrombotic disorders (e.g., thrombophlebitis, pulmonary embolism, cerebrovascular insufficiency, coronary occlusion, retinal thrombosis, mesenteric thrombosis). The drug should be discontinued immediately when any of these disorders occurs or is suspected.
If unexplained, sudden or gradual, partial or complete loss of vision; proptosis or diplopia; papilledema; retinal vascular lesions; or migraine occur during therapy with norethindrone, the drug should be discontinued and appropriate diagnostic and therapeutic measures instituted. Because steroidal hormones are metabolized in the liver, norethindrone should be used with caution in patients with impaired liver function.
Norethindrone is contraindicated in patients with thrombophlebitis, thromboembolic disorders, cerebral apoplexy, or a history of these conditions. The drug is also contraindicated in patients with undiagnosed vaginal bleeding, missed abortion, known sensitivity to the drug or any ingredient in the formulation, markedly impaired liver function or liver disease, or carcinoma of the breast or for use as a pregnancy test.