Pharmacokinetics

Absorption:

Norethindrone acetate is completely and rapidly deacetylated to norethindrone (NET) after oral administration, and the disposition of norethindrone acetate is indistinguishable from that of orally administered norethindrone. Norethindrone acetate is rapidly absorbed from norethindrone acetate tablets, with maximum plasma concentration of norethindrone generally occurring at about 2 hours post-dose. The pharmacokinetic parameters of norethindrone following single oral administration of norethindrone acetate in 29 healthy female volunteers are summarized in Table 1.

Table 1 Pharmacokinetic Parameters after a Single Dose of Norethindrone Acetate in Healthy Women

Norethindrone Acetate (n=29) Arithmetic Mean ± SD
Norethindrone (NET)
AUC (0-inf) (ng/ml*h)	166.90 ± 56.28
Cmax (ng/ml)	26.19 ± 6.19
tmax (h)	1.83 ± 0.58
t1/2 (h)	8.51 ± 2.19
AUC = area under the curve,
Cmax = maximum plasma concentration,
tmax = time at maximum plasma concentration,
t1/2 = half-life,
SD = standard deviation

Figure 1. Mean Plasma Concentration Profile after a Single Dose of 5 mg Administered to 29 Healthy Female Volunteers under Fasting Conditions

1. Cardiovascular disorders

Patients with risk factors for arterial vascular disease (e.g., hypertension, diabetes mellitus, tobacco use, hypercholesterolemia, and obesity) and/or venous thromboembolism (e.g., personal history or family history of VTE, obesity, and systemic lupus erythematosus) should be managed appropriately.

2. Visual abnormalities

Discontinue medication pending examination if there is a sudden partial or complete loss of vision or if there is sudden onset of proptosis, diplopia, or migraine. If examination reveals papilledema or retinal vascular lesions, medication should be discontinued.

General

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Because this drug may cause some degree of fluid retention, conditions which might be influenced by this factor, such as epilepsy, migraine, cardiac or renal dysfunctions, require careful observation

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In cases of breakthrough bleeding, and in all cases of irregular bleeding per vagina, nonfunctional causes should be borne in mind. In cases of undiagnosed vaginal bleeding, adequate diagnostic measures are indicated

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Patients who have a history of clinical depression should be carefully observed and the drug discontinued if the depression recurs to a serious degree

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Data suggest that progestin therapy may have adverse effects on lipid and carbohydrate metabolism. The choice of progestin, its dose, and its regimen may be important in minimizing these adverse effects, but these issues will require further study before they are clarified. Women with hyperlipidemias and/or diabetes should be monitored closely during progestin therapy

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The pathologist should be advised of progestin therapy when relevant specimens are submitted

Information for the Patient

Healthcare providers are advised to discuss the PATIENT INFORMATION leaflet with patients for whom they prescribe norethindrone acetate.

Drug/Laboratory Tests Interactions

The following laboratory test results may be altered by the use of estrogen/progestin combination drugs:

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Accelerated prothrombin time, partial thromboplastin time, and platelet aggregation time; increased platelet count; increased factors II, VII antigen, VIII antigen, VIII coagulant activity, IX, X, XII, VII-X complex, II-VII-X complex, and beta-thromboglobulin; decreased levels of antifactor Xa and antithrombin III, decreased antithrombin III activity; increased levels of fibrinogen and fibrinogen activity; increased plasminogen antigen and activity.

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Increased thyroid-binding globulin (TBG) levels leading to increased circulating total thyroid hormone levels as measured by protein-bound iodine (PBI), T4 levels (by column or by radioimmunoassay) or T3 levels by radio immunoassay. T3 resin uptake is decreased, reflecting the elevated TBG. Free T4 and free T3 concentrations are unaltered. Patients on thyroid replacement therapy may require higher doses of thyroid hormone.

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Other binding proteins may be elevated in serum (i.e., corticosteroid binding globulin (CBG), sex hormone binding globulin (SHBG)) leading to increased circulating corticosteroid and sex steroids, respectively. Free or biologically active hormone concentratios are unchanged. Other plasma proteins may be increased (angiotensinogen/renin substrate, alpha-1-antitrypsin, ceruloplasmin).

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Increased plasma HDL and HDL2 cholesterol subfraction concentrations, reduced LDL cholesterol concentration, increased triglycerides levels.

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Impaired glucose metabolism.

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Reduced response to metyrapone test.

Carcinogenesis, Mutagenesis, and Impairment of Fertility

Some beagle dogs treated with medroxyprogesterone acetate developed mammary nodules. Although nodules occasionally appeared in control animals, they were intermittent in nature, whereas nodules in treated animals were larger and more numerous, and persisted. There is no general agreement as to whether the nodules are benign or malignant. Their significance with respect to humans has not been established.

Pregnancy Category X

Norethindrone acetate is contraindicated during pregnancy as it may cause fetal harm when administered to pregnant women. Several reports suggest an association between intrauterine exposure to progestational drugs in the first trimester of pregnancy and congenital abnormalities in male and female fetuses. Some progestational drugs induce mild virilization of the external genitalia of female fetuses.

Nursing Mothers

Detectable amounts of progestins have been identified in the milk of mothers receiving them. Caution should be exercised when progestins are administered to a nursing woman.

Pediatric Use

Norethindrone acetate tablets are not indicated in children.

Secondary amenorrhea, abnormal uterine bleeding due to hormonal imbalance in the absence of organic pathology:

2.5 to 10 mg norethindrone acetate may be given daily for 5 to 10 days to produce secretory transformation of an endometrium that has been adequately primed with either endogenous or exogenous estrogen.

Progestin withdrawal bleeding usually occurs within three to seven days after discontinuing norethindrone acetate therapy. Patients with a past history of recurrent episodes of abnormal uterine bleeding may benefit from planned menstrual cycling with norethindrone acetate.

Endometriosis:

Initial daily dosage of 5 mg norethindrone acetate for two weeks. Dosage should be increased by2.5 mg per day every two weeks until 15 mg per day of norethindrone acetate is reached. Therapy may be held at this level for six to nine months or until annoying breakthrough bleeding demands temporary termination.

What is the most important information I should know about norethindrone acetate (A Progestin Hormone) tablets?

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Do not use norethindrone acetate if you are pregnant, breast-feeding or are trying to conceive.

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Do not use northindrone acetate if you have had a previous blood clot, stroke, or heart attack.

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Do not use norethindrone acetate if you are postmenopausal.

What is norethindrone acetate?

Norethindrone acetate is similar to the progesterone hormones naturally produced by the body. Your healthcare provider may provide norethindrone acetate as individual tablets.

What are norethindrone acetate tablets used for?

Norethindrone acetate tablets are used for the treatment of secondary amenorrhea (absence of menstrual periods in women who have previously had a menstrual period who are not pregnant), the treatment of endometriosis, and the treatment of irregular menstrual periods due to hormone imbalance.

Who should not take norethindrone acetate tablets?

You should not tke norethindrone acetate tablets if you are postmenopausal, pregnant or breast-feeding.

You should not take norethindrone acetate tablets if you have the following conditions:

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Known or suspected pregnancy. Norethindrone acetate tablets are not indicated during pregnancy as it may cause fetal harm when administered to pregnant women. There is an increased risk of minor birth defects in children whose mothers take norethindrone acetate during the first 4 months of pregnancy (mild masculinization of the external genitalia of the female fetus, as well as hypospadias in the male fetus). If you take norethindrone acetate and later find out you were pregnant, talk with your healthcare provider right away

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History of blood clots in the legs, lungs, eyes, brain, or elsewhere, or a past history of these conditions

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Liver impairment or disease

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Known or suspected cancer of the breast. If you have or had cancer of the breast, talk with your healthcare provider about whether you should take norethindrone acetate

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Undiagnosed vaginal bleeding

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Hypersensitivity to norethindrone acetate tablets. See the end of this leaflet for a list of all of the ingredients in norethindrone acetate

What are the risks associated with norethindrone acetate tablets?

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Risk to the Fetus:
Norethindrone acetate tablets should not be used if you are pregnant. Norethindrone acetate tablets are contraindicated during pregnancy as it may cause fetal harm when administered to pregnant women. There is an increased risk of minor birth defects in children whose mothers take this drug during the first 4 months of pregnancy. Several reports suggest an association between mothers who take these drugs in the first trimester of pregnancy and congenital abnormalities in male and female babies. Although it is not clear that these events were drug related, you should check with your healthcare provider about the risks to your unborn child of any medication taken during pregnancy.
You should avoid using norethindrone acetate tablets during pregnancy. If you take norethindrone acetate tablets and later find you were pregnant when you took it, be sure to discuss this with your healthcare provider as soon as possible.

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Abnormal Blood Clotting:
Use of progestational drugs, such as norethindrone acetate, has been associated with changes in the blood-clotting system. These changes allow the blood to clot more easily, possibly allowing clots to form in the bloodstream. If blood clots do form in your bloodstream, they can cut off the blood supply to vital organs, causing serious problems. These problems may include a stroke (by cutting off blood to part of the brain), a heart attack (by cutting off blood to part of the heart), a pulmonary embolus (by cutting off blood to part of the lungs), visual loss or blindness (by cutting off blood vessels in the eye), or other problems. Any of these conditions may cause death or serious long-term disability. Call your healthcare provider right away if you suspect you have any of these conditions. He or she may advise you to stop using the drug.

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Eye Abnormalities:
Discontinue norethindrone acetate tablets and call your healthcare provider right away if you experience sudden partial or complete loss of vision, blurred vision, or sudden onset of bulging eyes, double vision, or migraine.

What can I do to lower my chances of getting a serious side effect with norethindrone acetate?

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Talk with your healthcare provider regularly about whether you should continue taking norethindrone acetate

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Have a breast exam and mammogram (breast x-ray) every year unless your healthcare provider tells you something else. If members of your family have had breast cancer or if you have ever had breast lumps or an abnormal mammogram, you may need to have breast exams more often

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If you have high blood pressure, high cholesterol (fat in the blood), diabetes, are overweight, or if you use tobacco, you may have higher chances for getting heart disease. Ask your healthcare provider for ways to lower your chances of getting heart attacks

General information about the safe and effective use of norethindrone acetate tablets:

Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not take norethindrone acetate tablets for conditions for which it was not prescribed. Do not give norethindrone acetate tablets to other people, even if they have the same symptoms you have. It may harm them.

Keep norethindrone acetate tablets out of the reach of children.

This leaflet provides a summary of the most important information about progestin and/or estrogen therapy. If you would like more information, talk with your healthcare provider or pharmacist. You can ask for information about norethindrone acetate that is written for health professionals.

What are the ingredients in norethindrone acetate tablets?

Norethindrone acetate tablets contain the following inactive ingredients: colloidal silicon dioxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose and talc.

Manufactured by:

Glenmark Pharmaceuticals Ltd.
Colvale-Bardez, Goa 403 513, India

Manufactured for:

Glenmark Pharmaceuticals Inc., USA
Mahwah, NJ 07430

Questions? 1 (888)721-7115
www.glenmarkpharma.com/usa

February 2015