Generic name: norethindrone and ethinyl estradiol, and ferrous fumarate
Dosage form: tablets
Drug classes: Contraceptives , Sex hormone combinations
WARNING: CIGARETTE SMOKING AND SERIOUS CARDIOVASCULAR EVENTS Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive (COC) use. This risk increases with age, particularly in women over 35 years of age, and with the number of cigarettes smoked. For this reason, COCs are contraindicated in women who are over 35 years of age and smoke [see CONTRAINDICATIONS ( 4 )].
Indications and Usage for Wymzya Fe
WYMZYATM Fe is indicated for use by females of reproductive potential to prevent pregnancy.
Wymzya Fe Dosage and Administration
How to Start Wymzya Fe
Wymzya Fe is dispensed in a blister [see HOW SUPPLIED/STORAGE AND HANDLING ( 16 )]. Wymzya Fe may be started using either a Day 1 start or a Sunday start (see Table 1). For the first cycle of a Sunday Start regimen, an additional method of contraception should be used until after the first 7 consecutive days of administration.
How to Take Wymzya Fe
Wymzya Fe (white active tablets and brown placebo tablets) may be swallowed whole or chewed and swallowed. If the tablet is chewed, the patient should drink a full glass (8 ounces) of liquid immediately after swallowing.
|Table 1: Instructions for Administration of WYMZYA Fe|
|Starting CHCs in women not currently using hormonal contraception (Day 1 Start or Sunday Start)|
Consider the possibility of ovulation and conception prior to initiation of this product.
● WYMZYA Fe active tablets are white (Day 1 to Day 21).
● WYMZYA Fe placebo tablets are brown (Day 22 to Day 28).
|Day 1 Start:|
● Take first white active tablet on the first day of menses.
● Take subsequent white active tablets once daily at the same time each day for a total of 21 days.
● Take one brown placebo tablet daily for 7 days and at the same time of day that active tablets were taken.
● Begin each subsequent pack on the same day of the week as the first cycle pack (i.e., on the day after taking the last inactive tablet).
● Take first active tablet on the first Sunday after the onset of menses. Due to the potential risk of becoming pregnant, use additional non-hormonal contraception (such as condoms and spermicide) for the first seven days of the patient’s first cycle pack of WYMZYA Fe.
● Take subsequent white active tablets once daily at the same time each day for a total of 21 days.
● Take one brown placebo tablet daily for the following 7 days and at the same time of day that active tablets were taken.
● Begin each subsequent pack on the same day of the week as the first cycle pack (i.e., on the Sunday after taking the last inactive tablet) and additional non-hormonal contraceptive is not needed.
|Switching to WYMZYA Fe from another hormonal contraceptive||Start on the same day that a new pack of the previous hormonal contraceptive would have started.|
|Switching from another contraceptive method to WYMZYA Fe||Start WYMZYA Fe :|
|● Transdermal patch||● On the day when next application would have been scheduled|
|● Vaginal ring||● On the day when next insertion would have been scheduled|
|● Injection||● On the day when next injection would have been scheduled|
|● Intrauterine contraceptive||● On the day of removal|
● If the IUD is not removed on first day of the patient’s menstrual cycle, additional non-hormonal contraceptive (such as condoms and spermicide) is needed for the first seven days of the first cycle pack.
|● Implant||● On the day of removal|
|Complete instructions to facilitate patient counseling on proper tablet usage are located in the FDA-Approved Patient Labeling.|
Starting Wymzya Fe after Abortion or Miscarriage
- After a first-trimester abortion or miscarriage, Wymzya Fe may be started immediately. An additional method of contraception is not needed if Wymzya Fe is started within 5 days after termination of the pregnancy.
- If Wymzya Fe is not started within 5 days after termination of the pregnancy, the patient should use additional non-hormonal contraception (such as condoms and spermicide) for the first seven days of her first cycle pack of Wymzya Fe.
- Do not start until 4 weeks after a second-trimester abortion or miscarriage, due to the increased risk of thromboembolic disease. Start Wymzya Fe, following the instructions in Table 1 for Day 1 or Sunday start, as desired. If using Sunday start, use additional non- hormonal contraception (such as condoms and spermicide) for the first seven days of the patient’s first cycle pack of Wymzya Fe. [see CONTRAINDICATIONS ( 4 ), WARNINGS AND PRECAUTIONS ( 5.1 ), and FDA-APPROVED PATIENT LABELING.]
Starting Wymzya Fe after Childbirth
- Do not start until 4 weeks after delivery, due to the increased risk of thromboembolic disease. Start contraceptive therapy with Wymzya Fe following the instructions in Table 1 for women not currently using hormonal contraception.
- If the woman has not yet had a period postpartum, consider the possibility of ovulation and conception occurring prior to use of Wymzya Fe. [see CONTRAINDICATIONS ( 4 ), WARNINGS AND PRECAUTIONS ( 5.1 ), USE IN SPECIFIC POPULATIONS ( 8.1 and 8.3 ), and FDA-APPROVED PATIENT LABELING] .
|Table 2: Instructions for Missed Wymzya Fe Tablets|
|● If one white active tablet is missed in Weeks 1, 2, or 3||Take the tablet as soon as possible. Continue taking one tablet a day until the pack is finished.|
|● If two white active tablets are missed in Week 1 or Week 2||Take the two missed tablets as soon as possible and the next two active tablets the next day. Continue taking one tablet a day until the pack is finished. Additional non-hormonal contraception (such as condoms and spermicide) should be used as back-up if the patient has sex within 7 days after missing tablets.|
|● If two white active tablets are missed in Week 3 or three or more white active tablets are missed in a row in Weeks 1, 2, or 3||Day 1 start : Throw out the rest of the pack and start a new pack that same day.|
Sunday start : Continue taking one tablet a day until Sunday, then throw out the rest of the pack and start a new pack that same day.
Additional non-hormonal contraception (such as condoms and spermicide) should be used as back-up if the patient has sex within 7 days after missing tablets.
Advice in Case of Gastrointestinal Disturbances
In case of severe vomiting or diarrhea, absorption may not be complete and additional contraceptive measures should be taken. If vomiting or diarrhea occurs within 3 to 4 hours after taking an active tablet, handle this as a missed tablet [see FDA-APPROVED PATIENT LABELING].
Dosage Forms and Strengths
Wymzya Fe [norethindrone and ethinyl estradiol tablets USP (chewable) and ferrous fumarate tablets] is available in blister.
Each blister contains 28 tablets in the following order:
- 21 white to off-white, round (active), flat face, beveled edge tablets debossed with “LU” on one side and “M21” on the other side and each containing 0.4 mg norethindrone and 35 mcg ethinyl estradiol.
- 7 brown, mottled, round (non-hormonal placebo), flat face, beveled edge tablets debossed with “LU” on one side and “M22” on the other side and each containing 75 mg ferrous fumarate. The ferrous fumarate tablets do not serve any therapeutic purpose.
Wymzya Fe is contraindicated in females who are known to have or develop the following conditions:
- A high risk of arterial or venous thrombotic diseases. Examples include women who are known to:
- Smoke, if over age 35 [see BOXED WARNING and WARNINGS AND PRECAUTIONS ( 5.1 )]
- Have deep vein thrombosis or pulmonary embolism, now or in the past [see WARNINGS AND PRECAUTIONS ( 5.1 )]
- Have inherited or acquired hypercoagulopathies [see WARNINGS AND PRECAUTIONS ( 5.1 )]
- Have cerebrovascular disease [see WARNINGS AND PRECAUTIONS ( 5.1 )]
- Have coronary artery disease [see WARNINGS AND PRECAUTIONS ( 5.1 )]
- Have thrombogenic valvular or thrombogenic rhythm diseases of the heart (for example, subacute bacterial endocarditis with valvular disease, or atrial fibrillation) [see WARNINGS AND PRECAUTIONS ( 5.1 )]
- Have uncontrolled hypertension [see WARNINGS AND PRECAUTIONS ( 5.4 )]
- Have diabetes mellitus with vascular disease [see WARNINGS AND PRECAUTIONS ( 5.6 )]
- Have headaches with focal neurological symptoms or have migraine headaches with aura [see WARNINGS AND PRECAUTIONS ( 5.7 )]
Warnings and Precautions
Thrombotic Disorders and Other Vascular Problems
- Stop Wymzya Fe if an arterial thrombotic event or venous thromboembolic (VTE) event occurs.
- Stop Wymzya Fe if there is unexplained loss of vision, proptosis, diplopia, papilledema, or retinal vascular lesions. Evaluate for retinal vein thrombosis immediately.
- If feasible, stop Wymzya Fe at least 4 weeks before and through 2 weeks after major surgery or other surgeries known to have an elevated risk of VTE as well as during the following prolonged immobilization.
- Start Wymzya Fe no earlier than 4 weeks after delivery, in women who are not breastfeeding. The risk of postpartum VTE decreases after the third postpartum week, whereas the risk of ovulation increases after the third postpartum week.
- The use of COCs increases the risk of VTE. However, pregnancy increases the risk of VTE as much or more than the use of COCs. The risk of VTE in women using COCs is 3 to 9 per 10,000 woman-years. The risk of VTE is highest during the first year of use of COCs and when restarting hormonal contraception after a break of 4 weeks or longer. The risk of thromboembolic disease due to COCs gradually disappears after use is discontinued.
- Use of COCs also increases the risk of arterial thromboses such as strokes and myocardial infarctions, especially in women with other risk factors for these events. COCs have been shown to increase both the relative and attributable risks of cerebrovascular events (thrombotic and hemorrhagic strokes). The risk increases with age, particularly in women over 35 years of age who smoke.
- Use COCs with caution in women with cardiovascular disease risk factors.
Impaired Liver Function
Do not use Wymzya Fe in women with liver disease, such as acute viral hepatitis or severe (decompensated) cirrhosis of liver [see CONTRAINDICATIONS ( 4 )]. Acute or chronic disturbances of liver function may necessitate the discontinuation of COC use until markers of liver function return to normal and COC causation has been excluded. Discontinue Wymzya Fe if jaundice develops.
Wymzya Fe is contraindicated in women with benign and malignant liver tumors [see CONTRAINDICATIONS ( 4 )]. Hepatic adenomas are associated with COC use. An estimate of the attributable risk is 3.3 cases/100,000 COC users. Rupture of hepatic adenomas may cause death through intra-abdominal hemorrhage.
Studies have shown an increased risk of developing hepatocellular carcinoma in long-term (>8 years) COC users. However, the risk of liver cancers in COC users is less than one case per million users.
Risk of Liver Enzyme Elevations with Concomitant Hepatitis C Treatment
During clinical trials with the Hepatitis C combination drug regimen that contains ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, ALT elevations greater than 5 times the upper limit of normal (ULN),including some cases greater than 20 times the ULN, were significantly more frequent in women using ethinyl estradiol-containing medications, such as COCs. Discontinue Wymzya Fe prior to starting therapy with the combination drug regimen ombitasvir/paritaprevir/ritonavir, with or without dasabuvir [see CONTRAINDICATIONS ( 4 )].
Wymzya Fe can be restarted approximately 2 weeks following completion of treatment with the Hepatitis C combination drug regimen.
High Blood Pressure
Wymzya Fe is contraindicated in women with uncontrolled hypertension or hypertension with vascular disease [see CONTRAINDICATIONS ( 4 )]. For women with well-controlled hypertension, monitor blood pressure and stop Wymzya Fe if blood pressure rises significantly.
An increase in blood pressure has been reported in women taking COCs, and this increase is more likely in older women with extended duration of use. The incidence of hypertension increases with increasing concentrations of progestin.
Studies suggest a small increased relative risk of developing gallbladder disease among COC users. Use of COCs may worsen existing gallbladder disease. A past history of COC-related cholestasis predicts an increased risk with subsequent COC use. Women with a history of pregnancy-related cholestasis may be at an increased risk for COC related cholestasis.
Carbohydrate and Lipid Metabolic Effects
Carefully monitor prediabetic and diabetic women who take Wymzya Fe. COCs may decrease glucose tolerance.
Consider alternative contraception for women with uncontrolled dyslipidemia. A small proportion of women will have adverse lipid changes while on COCs.
Women with hypertriglyceridemia, or a family history thereof, may be at an increased risk of pancreatitis when using COCs.
If a woman taking Wymzya Fe develops new headaches that are recurrent, persistent, or severe, evaluate the cause and discontinue Wymzya Fe if indicated.
Consider discontinuation of Wymzya Fe in the case of increased frequency or severity of migraine during COC use (which may be prodromal of a cerebrovascular event).
Bleeding Irregularities and Amenorrhea
Unscheduled Bleeding and Spotting
Unscheduled (breakthrough or intracyclic) bleeding and spotting sometimes occur in patients on COCs, especially during the first three months of use. If bleeding persists or occurs after previously regular cycles, check for causes such as pregnancy or malignancy. If pathology and pregnancy are excluded, bleeding irregularities may resolve over time or with a change to a different contraceptive product.
Amenorrhea and Oligomenorrhea
Women who use Wymzya Fe may experience amenorrhea. Some women may experience amenorrhea or oligomenorrhea after discontinuation of COCs, especially when such a condition was preexistent.
If scheduled (withdrawal) bleeding does not occur, consider the possibility of pregnancy. If the patient has not adhered to the prescribed dosing schedule (missed one or more active tablets or started taking them on a day later than she should have), consider the possibility of pregnancy at the time of the first missed period and take appropriate diagnostic measures. If the patient has adhered to the prescribed regimen and misses two consecutive periods, rule out pregnancy.
COC Use Before or During Early Pregnancy
Extensive epidemiologic studies have revealed no increased risk of birth defects in women who have used oral contraceptives prior to pregnancy. Studies also do not suggest a teratogenic effect, particularly in so far as cardiac anomalies and limb reduction defects are concerned, when oral contraceptives are taken inadvertently during early pregnancy. Discontinue Wymzya Fe use if pregnancy is confirmed.
Administration of COCs to induce withdrawal bleeding should not be used as a test for pregnancy [see USE IN SPECIFIC POPULATIONS ( 8.1 )].
Carefully observe women with a history of depression and discontinue Wymzya Fe if depression recurs to a serious degree.
5.11 Malignant Neoplasms
Wymzya Fe is contraindicated in females who currently have or have had breast cancer because breast cancer may be hormonally sensitive [see CONTRAINDICATIONS (4)].
Epidemiology studies have not found a consistent association between use of combined oral contraceptives (COCs) and breast cancer risk. Studies do not show an association between ever (current or past) use of COCs and risk of breast cancer. However, some studies report a small increase in the risk of breast cancer among current or recent users (<6 months since last use) and current users with longer duration of COC use [see POSTMARKETING EXPERIENCE (6.2)].
A causal relationship between the use of CHCs and the development of cervical cancer and intraepithelial neoplasia has not been clearly established. Some studies suggest that COCs are associated with an increase in the risk of cervical cancer or intraepithelial neoplasia. However, there is controversy about the extent to which these findings may be due to differences in sexual behavior and other factors.
Effect on Binding Globulins
The estrogen component of COCs may raise the serum concentrations of thyroxine-binding globulin, sec hormone-binding globulin, and cortisol-binding globulin. The dose of replacement thyroid hormone or cortisol therapy may need to be increased.
A woman who is taking COCs should have a yearly visit with her healthcare provider for a blood pressure check and for other indicated healthcare.
In women with hereditary angioedema, exogenous estrogens may induce or exacerbate symptoms of angioedema.
Chloasma may occasionally occur, especially in women with a history of chloasma gravidarum. Women with a tendency to chloasma should avoid exposure to the sun or ultraviolet radiation while taking Wymzya Fe.
Five studies that compared breast cancer risk between ever-users (current or past use) of COCs and never-users of COCs reported no association between ever use of COCs and breast cancer risk, with effect estimates ranging from 0.90 – 1.12 (Figure 1).
Three studies compared breast cancer risk between current or recent COC users (<6 months since last use) and never users of COCs (Figure 1). One of these studies reported no association between breast cancer risk and COC use. The other two studies found an increased relative risk of 1.19 – 1.33 with current or recent use. Both of these studies found an increased risk of breast cancer with current use of longer duration, with relative risks ranging from 1.03 with less than one year of COC use to approximately 1.4 with more than 8-10 years of COC use.
Figure 1: Risk of Breast Cancer with Combined Oral Contraceptive Use
RR = relative risk; OR = odds ratio; HR = hazard ratio. “ever COC” are females with current or past COC use; “never COC use” are females that never used COCs.
The following serious adverse reactions with the use of COCs are discussed elsewhere in the labeling:
- Serious cardiovascular events and stroke [see BOXED WARNING and WARNINGS AND PRECAUTIONS (5.1)]
- Vascular events [see WARNINGS AND PRECAUTIONS (5.1)]
- Liver disease [see WARNINGS AND PRECAUTIONS (5.2)]
The following adverse reactions are commonly reported by COC users. Because these reactions are voluntarily reported by from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure:
- Irregular uterine bleeding
- Breast tenderness
Consult the labeling of concurrently used drugs to obtain further information about interactions with hormonal contraceptives or the potential for enzyme alterations.
Effects of Other Drugs on Combined Oral Contraceptives
Substances Decreasing the Plasma Concentrations of COCs and Potentially Diminishing the Efficacy of COCs
Drugs or herbal products that induce certain enzymes, including cytochrome P450 3A4 (CYP3A4), may decrease the plasma concentrations of COCs and potentially diminish the effectiveness of COCs or increase breakthrough bleeding. Some drugs or herbal products that may decrease the effectiveness of hormonal contraceptives include phenytoin, barbiturates, carbamazepine, bosentan, felbamate, griseofulvin, oxcarbazepine, rifampicin, topiramate, rifabutin, rufinamide, aprepitant, and products containing St. John’s wort. Interactions between hormonal contraceptives and other drugs may lead to breakthrough bleeding and/or contraceptive failure. Counsel women to use an alternative method of contraception or a back-up method when enzyme inducers are used with COCs, and to continue back-up contraception for 28 days after discontinuing the enzyme inducer to ensure contraceptive reliability.
Colesevelam, a bile acid sequestrant, given together with a COC, has been shown to significantly decrease the AUC of EE. The drug interaction between the contraceptive and colesevelam was decreased when the two drug products were given 4 hours apart.
Substances Increasing the Plasma Concentrations of COCs
Co-administration of atorvastatin or rosuvastatin and certain COCs containing EE increase AUC values for EE by approximately 20 to 25%. Ascorbic acid and acetaminophen may increase plasma EE concentrations, possibly by inhibition of conjugation. CYP3A4 inhibitors, such as itraconazole, fluconazole, grapefruit juice, or ketoconazole may increase plasma hormone concentrations.
Human Immunodeficiency Virus (HIV)/Hepatitis C Virus (HCV) Protease Inhibitors and Non- nucleoside Reverse Transcriptase Inhibitors
Significant changes (increase or decrease) in the plasma concentrations of estrogen and/or progestin have been noted in some cases of co-administration with HIV protease inhibitors (decrease [e.g., nelfinavir, ritonavir, darunavir/ritonavir, (fos)amprenavir/ritonavir, lopinavir/ritonavir, and tipranavir/ritonavir] or increase [e.g., indinavir and atazanavir/ritonavir])/HCV protease inhibitors (decrease [e.g., nevirapine] or increase [e.g., etravirine]).
Effects of Combined Oral Contraceptives on Other Drugs
COCs containing EE may inhibit the metabolism of other compounds (e.g., cyclosporine prednisolone, theophylline, tizanidine, and voriconazole) and increase their plasma concentrations. COCs have been shown to decrease plasma concentrations of acetaminophen, clofibric acid, morphine, salicylic acid, temazepam and lamotrigine. Significant decrease in plasma concentration of lamotrigine has been shown, likely due to induction of lamotrigine glucuronidation. This may reduce seizure control; therefore, dosage adjustments of lamotrigine may be necessary.
Women on thyroid hormone replacement therapy may need increased doses of thyroid hormone because the serum concentration of thyroid-binding globulin increases with use of COCs [see WARNINGS AND PRECAUTIONS ( 5.12 )].
Concomitant Use with HCV Combination Therapy – Liver Enzyme Elevation
Do not co-administer Wymzya Fe with HCV drug combinations containing ombitasvir/ paritaprevir/ritonavir, with or without dasabuvir, due to potential for ALT elevations [see WARNINGS AND PRECAUTIONS ( 5.3 )].
Interference with Laboratory Tests
The use of contraceptive steroids may influence the results of certain laboratory tests, such as coagulation factors, lipids, glucose tolerance, and binding proteins.
USE IN SPECIFIC POPULATIONS
There is little or no increased risk of birth defects in women who inadvertently use COCs during early pregnancy. Epidemiologic studies and meta-analyses have not found an increased risk of genital or non-genital birth defects (including cardiac anomalies and limb reduction defects) following exposure to low dose COCs prior to conception or during early pregnancy.
Do not use COCs to induce withdrawal bleeding as a test for pregnancy. Do not use COCs during pregnancy to treat threatened or habitual abortion.
Advise the nursing mother to use other forms of contraception, when possible, until she has weaned her child. COCs can reduce milk production in breastfeeding mothers. This is less likely to occur once breastfeeding is well-established; however, it can occur at any time in some women. Small amounts of oral contraceptive steroids and/or metabolites are present in breast milk.
Safety and efficacy of Wymzya Fe have been established in women of reproductive age. Efficacy is expected to be the same in post-pubertal adolescents under the age of 18 years as for users 18 years and older. Use of this product before menarche is not indicated.
Wymzya Fe has not been studied in postmenopausal women and is not indicated in this population.
The pharmacokinetics of Wymzya Fe has not been studied in women with hepatic impairment. However, steroid hormones may be poorly metabolized in patients with hepatic impairment. Acute or chronic disturbances of liver function may necessitate the discontinuation of COC use until markers of liver function return to normal and COC causation has been excluded [see CONTRAINDICATIONS ( 4 ) and WARNINGS AND PRECAUTIONS ( 5.2 )].
The pharmacokinetics of Wymzya Fe has not been studied in women with renal impairment.
There have been no reports of serious ill effects from overdosage of oral contraceptives, including ingestion by children. Overdosage may cause withdrawal bleeding in females and nausea.
Wymzya Fe Description
Wymzya Fe is a combinational contraceptive containing the progestational compound norethindrone and the estrogenic compound ethinyl estradiol. The packaging includes 21 white tablets composed of norethindrone and ethinyl estradiol followed by 7 brown ferrous fumarate (placebo) tablets. The chemical name for norethindrone is 17-hydroxy-19-nor-17α-pregn-4-en-20-yn-3-one and for ethinyl estradiol the chemical name is 19-nor-17α-pregna-1,3,5(10)-trien-20-yne-3,17-diol. The structural formulas are:
The active white Wymzya Fe tablets contain 0.4 mg norethindrone and 0.035 mg ethinyl estradiol, and the following inactive ingredients: lactose anhydrous, magnesium stearate, mannitol, microcrystalline cellulose, povidone, sodium starch glycolate, sucralose, vanillin and vitamin E.
The brown tablets contain ferrous fumarate, magnesium stearate, microcrystalline cellulose, povidone, sodium starch glycolate and sucrose. The ferrous fumarate tablets do not serve any therapeutic purpose.
Wymzya Fe – Clinical Pharmacology
Mechanism of Action
COCs lower the risk of becoming pregnant primarily by suppressing ovulation. Other possible mechanisms may include cervical mucus changes that inhibit sperm penetration and endometrial changes that reduce the likelihood of implantation.
No specific pharmacodynamic studies were conducted with Wymzya Fe.
Ethinyl estradiol and norethindrone are rapidly absorbed with maximum plasma concentrations occurring within 2 hours after Wymzya Fe administration (see Table 1). Norethindrone appears to be completely absorbed following oral administration; however, it is subject to first-pass metabolism resulting in an absolute bioavailability of approximately 65 percent. Large intersubject variability is reflected in a 3- to 5-fold variation in norethindrone bioavailability. Ethinyl estradiol bioavailability is approximately 43 percent due to small-intestinal and hepatic first-pass metabolism.
|Norethindrone/Ethinyl Estradiol||tmax (h)||Cmax (pg/mL)||AUC0 to ∞|
|Norethindrone 0.4 mg||1.24 ± 0.40 *||4210.6 ± 1628.8 *||18034.9 ± 7852.9 †||8.6 ± 3.7 †|
|Ethinyl Estradiol 35 mcg||1.44 ± 0.33 †||131.4 ± 34.2 †||1065.8 ± 276.2 †||17.1 ± 4.4 †|
|* n = 26 † n = 25|
Cmax = maximum plasma concentration; tmax = time to reach Cmax; AUC = area under the curve;
t1/2 = elimination half- life.
Single-dose administration of Wymzya Fe tablets with food decreased the maximum norethindrone and ethinyl estradiol concentration by 53 percent and 47 percent, respectively; the extent of norethindrone and ethinyl estradiol absorption (AUC values) was not affected by food administration.
Norethindrone is 36 percent bound to sex hormone-binding globulin (SHBG) and 61 percent bound to albumin. Ethinyl estradiol is not bound to SHBG but is highly (98.5 percent) bound to albumin. Volume of distribution of norethindrone and ethinyl estradiol ranges from 2 to 4 L/kg.
Norethindrone undergoes extensive biotransformation, primarily via reduction, followed by sulfate and glucuronide conjugation; less than 5 percent of a norethindrone dose is excreted unchanged; greater than 50 percent and 20 to 40 percent of a dose is excreted in urine and feces, respectively. The majority of metabolites in the circulation are sulfates, with glucuronides accounting for most of the urinary metabolites.
Ethinyl estradiol is also extensively metabolized, both by oxidation and by conjugation with sulfate and glucuronide. Sulfates are the major circulating conjugates of ethinyl estradiol, and glucuronides predominate in urine. The primary oxidative metabolite is 2-hydroxy-ethinyl estradiol, which is formed by the CYP3A4 isoform of cytochrome P450.
Plasma clearance values for norethindrone and ethinyl estradiol are similar (approximately 0.4 L/hr/kg). Ethinyl estradiol and norethindrone are excreted in both urine and feces, primarily as metabolites. Ethinyl estradiol is excreted in urine and feces as glucuronides and sulfates, and about 28 to 43 percent undergoes enterohepatic circulation. The mean terminal elimination half- lives of norethindrone and ethinyl estradiol following single dose administration of Wymzya Fe are approximately 9 hours and 17 hours, respectively.
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