Norethindrone
Mechanism :
Progestins like norethindrone act on target cells by attaching to progesterone receptors, which leads to alterations in the target genes down the line. The reproductive system, skeletal tissue, pituitary, hypothalamus, breast and central nervous system all contain target cells. The main source of contraceptive effectiveness is alterations to the cervical mucus, where norethisterone makes the mucus more viscous and cell-rich to prevent sperm movement and transport. The endometrium is altered by norethisterone in a number of ways that render it unsuitable for implantation, including atrophy, erratic secretion, and reduced proliferation. It slows pregnancy of relase of GnRH hormone from hypothalamus there by blunt LH surgery preventing follicler maturation.
Indication :
- Oral contraceptive medication: especially indicated in post-menarchal women
- Abnormal uterine bleeding
- Endometriosis and related pain
- Secondary amenorrhea
Contraindications :
• Hypersensitivity to drug or its components.
• Pregnancy, known/ suspected
• CA breast, known/suspected
• Undiagnosed vaginal bleeding
• Liver tumor: benign/malignant
• Active liver disorder
• Thromboembolism
• caution in smokers
• caution if breastfeeding within 6 weeks of delivery
• caution in kidney disorders
Dosing :
Dosage form: TAB: 0.35 mg.
In women, OCP dose:1 tablet, oral route, qd.
Amenorrhea with abnormal uterine bleeding: Females: Orally, take 2.5 to 10 mg of norethindrone acetate daily for 5-10 days. When the endometrium is sufficiently stimulated with either endogenous or exogenous oestrogen, secretory transformation will take place. Within 3 to 7 days of stopping norethindrone acetate, withdrawal bleeding may be anticipated.
Using contraception: Norethindrone oral dosage: 0.35 mg daily (do not miss any days)
On the first day of your period or the day after a miscarriage or abortion, start taking the drug. If switching from a combined oral contraceptive, begin the day after taking the last active combined tablet.
The missed dose should be taken as soon as you remember. For 48 hours, a backup method of contraception should be used if the dose is taken more than three hours late.
Endometriosis: Norethindrone acetate, taken orally, is administered in the following dosages: 5 mg/day for 14 days; 2.5 mg/day increases every two weeks to 15 mg/day;
continue for 6 to 9 months or until breakthrough bleeding requires temporary stop.
Adverse Effect :
Edema, pulmonary embolism, retinal thrombosis, deep vein thrombosis, cerebral thrombosis, and retinal thrombosis are all cardiovascular adverse events.
Central nervous system: emotional lability, anxiety, headaches, dizziness, exhaustion, and migraines
Dermatologic conditions include urticaria, chloasma, itching, hair loss, and acne vulgaris.
Endocrine & metabolic: weight gain, hirsutism, hypermenorrhea, amenorrhea, and menstrual disorders
gastrointestinal: nausea, emesis, and discomfort in the abdomen
Genitourinary: Vaginal bleeding, breast pain, spotting, breast discomfort, breast enlargement, cervical erosion, change in cervical secretions, and reduced lactation
Anaphylaxis, allergic reactions
Hepatic: Deranged LFTs, hepatitis, and cholestatic jaundice
Arm and leg pain are skeletal and neuromuscular issues.
Optic neuritis in the eye (with or without vision loss)
Interaction :
Acitretin, anticoagulants, anti diabetic agents, barbiturates, griseofulvin, mifepristone, phenytoin, fosphenytoin, retinoic acid derivatives, selegiline and thalidomide are some drugs that can interact with this drug.
Lactation :
Drug of choice for contraception while breastfeeding, however must be started >6weeks after delivery. There is no known risk of deleterious effect on the newborn based on limited human data. There is some evidence of possible reduction in milk production in early postpartum based on conflicting human data and drug's mechanism of action.
Hepatic Dose :
Contraindicated in active hepatic disease.
Pregnanacy :
Contraindicated during pregnancy as its primary indication is contraception however there is no known risk of teratogenicity when used during early pregnancy based on available human data.