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Norethisterone

G03D - Progestogens ATC G03DC02 Small molecule approved 1962 Oral Natural product Black-box warning

JFDA label: Aminor 5mg Tablets

⚠ Black-Box Warning

Mechanism of Action

Agonist of Progesterone receptor — Progesterone receptor agonist

TargetActionGene / class
Progesterone receptor efficacy AGONIST PGR

Indications

Approved

  • Abnormal uterine bleeding (norethindrone acetate)
  • Amenorrhea, secondary (norethindrone acetate)
  • Contraception (norethindrone)
  • Endometriosis (norethindrone acetate)

Contraindications

Source: Lexicomp

  • Estrogen or progestin dependent malignant tumor Absolute
  • Hypersensitivity to norethindrone or any component of the formulation Absolute
  • active or recent history of arterial thromboembolic disease (eg, stroke, MI) Absolute
  • as a diagnostic test for pregnancy Additional contraindications in Absolute
  • breast cancer (known, suspected, or history of) Absolute
  • hepatic impairment or disease Absolute
  • missed abortion Absolute
  • partial or complete vision loss due to ophthalmic vascular disease Absolute
  • pregnancy Norethindrone: Additional contraindications: Benign or malignant liver tumors Norethindrone acetate: Additional contraindications: DVT or PE (current or history of) Absolute
  • undiagnosed abnormal genital bleeding Absolute

Adverse Reactions

Very Common >10%Common 1–10%Uncommon 0.1–1% Rare 0.01–0.1%Very Rare <0.01%Not Known

Cardiac disorders (6)

Not Known Cerebral embolism · cerebral thrombosis · deep vein thrombosis · edema · pulmonary embolism · retinal thrombosis

Nervous system disorders (8)

Not Known Depression · dizziness · emotional lability · fatigue · headache · insomnia · migraine · nervousness

Hepatobiliary disorders (3)

Not Known abnormal hepatic function tests · Cholestatic jaundice · hepatitis

Renal and urinary disorders (10)

Not Known Breakthrough bleeding · breast hypertrophy · breast tenderness · cervical erosion · change in cervical secretions · decreased lactation · genital discharge · mastalgia · spotting · vaginal hemorrhage

Immune system disorders (2)

Not Known Anaphylaxis · hypersensitivity

Metabolism and nutrition disorders (5)

Not Known Amenorrhea · hirsutism · hypermenorrhea · menstrual disease · weight gain

Gastrointestinal disorders (3)

Not Known Abdominal pain · nausea · vomiting

Skin and subcutaneous tissue disorders (6)

Not Known Acne vulgaris · alopecia · chloasma · pruritus · skin rash · urticaria

Musculoskeletal and connective tissue disorders (2)

Not Known Arm pain · leg pain

Eye disorders (1)

Not Known Optic neuritis (with or without vision loss)

Dosing

Source: Lexicomp

Abnormal uterine bleeding and amenorrhea: Females: Oral: Norethindrone acetate: 2.5 to 10 mg/day for 5 to 10 days. Secretory transformation of the endometrium will occur when adequately primed with endogenous or exogenous estrogen. Withdrawal bleeding may be expected within 3 to 7 days after discontinuing norethindrone acetate. Contraception: Females: Oral: Norethindrone: 0.35 mg every day (no missed days) Initial dose: Start on first day of menstrual period or the day after a miscarriage or abortion. If switching from a combined oral contraceptive, begin the day after finishing the last active combined tablet. Missed dose: Take as soon as remembered. A back up method of contraception should be used for 48 hours if dose is taken ≥3 hours late. Additional contraception dosing considerations (Curtis 2016a): Initiation of therapy: May be started at any time in the menstrual cycle once it is determined that the woman is not pregnant. Back-up contraception is not needed if started within 5 days of onset of menstruation. If started >5 days after the onset of menstruation or at any time in a women experiencing amenorrhea (not postpartum), back up contraception should be used for 2 days. Switching from a different contraceptive to a progestin-only contraceptive: May be started at any time if it is determined that the woman is not pregnant. Unless the woman abstains from sexual intercourse, a backup method of contraception is needed if it has been >5 days since menstrual bleeding has begun. When an additional method of contraception is needed, consider continuing the woman’s previous method for 2 days after starting the progestin-only contraceptive. Switching from an IUD to a progestin-only contraceptive: Continue the IUD for at least 2 days after the progestin-only contraceptive is started or advise the woman to abstain from sexual intercourse or use a barrier contraceptive for 7 days before removing the IUD. Alternately, an emergency contraceptive may be used at the time of IUD removal. Endometriosis: Females: Oral: Norethindrone acetate: 5 mg/day for 14 days; increase at increments of 2.5 mg/day every 2 weeks to reach 15 mg/day; continue for 6 to 9 months or until breakthrough bleeding demands temporary termination
(For additional information see "Norethindrone: Pediatric drug information") Adolescents: Refer to adult dosing
There are no dosage adjustments provided in the manufacturer’s labeling.
There are no dosage adjustments provided in the manufacturer’s labeling. However, use is contraindicated in patients with hepatic tumors or impairment.

Warnings & Precautions

Source: Lexicomp

Bleeding

Irregular menstrual bleeding patterns are common with progestin-only contraceptives; nonpharmacologic causes of abnormal bleeding should be ruled out.

Breast cancer

The use of combination hormonal contraceptives has been associated with a slight increase in the frequency of breast cancer, however studies are not consistent. Data is insufficient to determine if progestin-only contraceptives also increase this risk. Norethindrone and norethindrone acetate are contraindicated in women with breast cancer.

Delayed follicular atresia/ovarian cysts

If follicular development occurs following use for contraception, follicles may grow and enlarge beyond the size attained in a normal cycle. May be asymptomatic or can be associated with mild abdominal pain; surgical intervention is rarely required.

Ectopic pregnancy

The possibility of ectopic pregnancy following use of a progestin-only contraceptive should be considered in patients with lower abdominal pain.

Lipid effects

May have adverse effects on lipid metabolism; use caution in women with hyperlipidemias.

Visual abnormalities

Norethindrone acetate: Discontinue if migraine, loss of vision, proptosis, diplopia, or other visual disturbances occur; discontinue permanently if papilledema or retinal vascular lesions are observed on examination. Disease-related concerns:

Cardiovascular disease

Norethindrone acetate: Risk factors for cardiovascular disorders include diabetes mellitus, hypercholesterolemia, hypertension, SLE, obesity, tobacco use, and/or history of venous thromboembolism (VTE). Risk factors should be managed appropriately.

Depression

Norethindrone acetate: Use with caution in patients with depression. Progestin only contraceptive tablets may be used in women with depression (Curtis 2016b).

Diabetes

May have adverse effects on glucose tolerance; use caution in women with diabetes. Progestin only contraceptive tablets may be used in women with diabetes (Curtis 2016b).

Diseases exacerbated by fluid retention

Norethindrone acetate: Use with caution in patients with diseases which may be exacerbated by fluid retention, including asthma, epilepsy, or cardiac or renal dysfunction.

Hepatic adenomas

Extremely rare hepatic adenomas and focal nodular hyperplasia resulting in fatal intra-abdominal hemorrhage have been reported in association with long-term combination oral contraceptive use. Data is insufficient to determine if progestin-only contraceptives also increase this risk. Use as a contraceptive is contraindicated in women with hepatic tumors.

Migraine

Use with caution in patients with a history of migraine. Progestin-only contraceptive tablets may be used in women with a history of headache or migraine; new headaches or changes in headaches should be evaluated (Curtis 2016b). Concurrent drug therapy issues:

Drug-drug interactions

Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Special populations:

Pediatric

Not for use prior to menarche.

Smokers

Progestin-only contraceptives may be used in women who smoke (Curtis 2016b). Because of an increased risk of cardiovascular disease, women using oral contraceptives should be strongly advised not to smoke. Other warnings/precautions:

Appropriate use

Norethindrone: Progestin-only contraceptives contain less progestin than contained in estrogen/progestin–combined contraceptives. Risks associated with estrogen/progestin contraceptives should be considered for progestin-only products.

HIV infection protection

Progestin-only contraceptives do not protect against HIV infection or other sexually transmitted diseases.

Laboratory changes

The use of estrogens and/or progestins may change the results of some laboratory tests (eg, coagulation factors, lipids, glucose tolerance, binding proteins). The dose, route, and the specific estrogen/progestin influence these changes. In addition, personal risk factors (eg, cardiovascular disease, smoking, diabetes, age) also contribute to adverse events; use of specific products may be contraindicated in women with certain risk factors.

Pregnancy & Lactation

Pregnancy

FDA category X Contraindicated

Use is contraindicated during pregnancy. First trimester exposure of progestins may cause genital abnormalities including hypospadias in male infants and mild virilization of external female genitalia. Changes in external genitalia have been reported in female infants exposed to norethindrone acetate (Fine 1963). Significant adverse events related to growth and development have not been observed following use of oral progestins in contraceptive doses (limited studies). Norethindrone: Progestin-only contraceptives may be started immediately postpartum (Curtis 2016a; Curtis 2016b). A rapid return to fertility occurs when progestin-only contraceptives are discontinued. Norethindrone acetate: The contraceptive dose of norethindrone acetate is not known. Barrier contraception is recommended to prevent unintended pregnancy (eg, when treating endometriosis) (Kaser 2012).

Lactation

Progestins are found in breast milk (1% to 6% of maternal serum concentration) and can be detected in infant plasma. Isolated reports of decreased milk production and very rare reports of jaundice in breastfeeding infants have been noted. In general, adverse events related to infant growth and development have not been reported. The manufacturer of norethindrone acetate recommends that caution be used if administered to a breastfeeding woman. When used for contraception, may be started at any

Monitoring

Clinical pearlNorethindrone: Contraception: Assessment of pregnancy status (prior to therapy); weight (optional; BMI at baseline may be helpful to monitor changes during therapy); assess potential health status changes at routine visits (Curtis 2016a). Norethindrone acetate: Monitor patient for vision changes; signs or symptoms of depression; glycemic control in patients with diabetes; lipid profiles in patients being treated for hyperlipidemias. Regardless of indication, adequate diagnostic measures, including endometrial sampling, if indicated, should be performed to rule out malignancy in all cases of undiagnosed abnormal vaginal bleeding. Pathologist should be informed of therapy when submitting endometrial tissue for histologic evaluation.

Chemistry & Properties

2D structure
FormulaC20H26O2
Molecular weight298.43 g/mol
IUPAC name(8R,9S,10R,13S,14S,17R)-17-ethynyl-17-hydroxy-13-methyl-1,2,6,7,8,9,10,11,12,14,15,16-dodecahydrocyclopenta[a]phenanthren-3-one
CAS68-22-4
PubChem CID6230
InChIKeyVIKNJXKGJWUCNN-XGXHKTLJSA-N
logP3.49 (XLogP 3.0)
Polar surface area37.3 Ų
H-bond acceptors / donors2 / 1
Drug-likeness (QED)0.70
Lipinski violations0
SMILESC#C[C@]1(O)CC[C@H]2[C@@H]3CCC4=CC(=O)CC[C@@H]4[C@H]3CC[C@@]21C

Biology & Pharmacokinetics

Pharmacokinetics

BBB penetrantNo

Enzyme interactions

EnzymeRoleDetail
CYP1A2Substrate
CYP2B6Inhibitor
CYP2C19Inhibitor
CYP2C19Substrate
CYP2C8Inhibitor
CYP3A4Substrate

Receptor binding (top 1)

TargetActionAffinity
Progesterone receptor (PGR) Agonist pEC50 8.7

Transporters

BCRP (Inhibitor)BSEP (Inhibitor)BSEP (Inhibitor)MDR1 (Inhibitor)MRP1 (Inhibitor)MRP2 (Inhibitor)MRP3 (Inhibitor)MRP4 (Inhibitor)OATP1B1 (Inhibitor)OATP1B1 (Inhibitor)OATP1B3 (Inhibitor)OATP1B3 (Inhibitor)OATP2B1 (Inhibitor)P-gp (Inhibitor)MDR1 (Substrate)P-gp (Substrate)

Drug–drug interactions (100+, DDInter)

Interacting drugSeverityManagement
Acitretin major
Bexarotene major
Brigatinib major
Carfilzomib major
Dabrafenib major
Encorafenib major
Griseofulvin major
Lumacaftor major
Mycophenolic acid major
Sugammadex major
Tranexamic acid major
Acarbose moderate
Acetohexamide moderate
Adalimumab moderate
Albiglutide moderate
Alefacept moderate
Alogliptin moderate
Aminoglutethimide moderate
Aminophylline moderate
Anakinra moderate
Apalutamide moderate
Aprepitant moderate
Artemether moderate
Asparaginase Escherichia coli moderate
Canagliflozin moderate
Canakinumab moderate
Certolizumab pegol moderate
Chlorpropamide moderate
Cladribine moderate
Clarithromycin moderate
Clotrimazole moderate
Cobicistat moderate
Cyclosporine moderate
Dapagliflozin moderate
Dasatinib moderate
Deferasirox moderate
Dulaglutide moderate
Elagolix moderate
Emapalumab moderate
Empagliflozin moderate

Showing 40 of 100+.

Registered Products (6)

BrandForm / strengthPackAgentCitizen (JOD)
Aminor Tablet 5 mg 20 tab pack varies Hikma Pharmaceuticals Co.Ltd/Jordan 1.540
Primotan-N 5mg (Norethisterone) Tablets Tablet 5 mg 30 tab Al-Motakadema Pharmaceutical LTD. 1.810
Aminor Tablet 5 mg 30 tab pack varies Hikma Pharmaceuticals Co.Ltd/Jordan 2.310
PRIMOLUT NOR Tab Tablet 5 mg 30 tab The Jordan Drugstore Co 2.590
TRISEQUENS TABS Tablet 2, 2, 1 mg, 0, 1, 0 mg 2 mg Khoury Drug Store 4.890
Kliogest Tablet Tablet 1 mg, 2 mg 28 tab Khoury Drug Store 5.320