norethindrone

Action and Spectrum

Actions and Spectrum: 

• Contraception: norethindrone is commonly used as a form of hormonal contraception. It is available as an oral contraceptive pill, a contraceptive injection, and an intrauterine device (IUD). In all forms, norethindrone works by preventing ovulation, thickening cervical mucus, and altering the endometrial lining to prevent implantation  
• Menstrual disorders: norethindrone is also used to treat many menstrual disorders, including heavy menstrual bleeding, irregular periods, and painful periods. By regulating the menstrual cycle, norethindrone can help reduce symptoms associated with these conditions. 
• Endometriosis: norethindrone is used to treat endometriosis, causing pain and other symptoms. By suppressing the growth of the endometrial tissue, norethindrone can reduce pain and other symptoms associated with endometriosis. 
• Hormone replacement therapy (HRT): norethindrone is sometimes used as hormone replacement therapy for postmenopausal women. When combined with estrogen, norethindrone can help reduce endometrial hyperplasia and endometrial cancer. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Edema 

Weakness 

Breakthrough bleeding 

Deep vein thrombosis 

Anorexia 

Amenorrhea 

Thrombophlebitis 

Headache 

Nervousness 

Somnolence 

Breast tenderness 

Depression 

Dizziness 

Nausea 

Vomiting 

Cholestatic jaundice 

Spotting 

Change in menstrual flow 

Galactorrhea 

Abdominal pain 

Weight change 

Black Box Warning

Contraindication / Caution

Contraindication/Caution: 

• Hypersensitivity: norethindrone should not be used in individuals who are hypersensitive or allergic to the medication or its components. 
• Pregnancy: norethindrone is contraindicated during pregnancy, as it may harm the developing fetus. 
• Breastfeeding: norethindrone can pass into breast milk and may harm a nursing baby. It is recommended to avoid using norethindrone while breastfeeding. 
• History of blood clots: norethindrone should be used cautiously in individuals with blood clot history. 
• Liver disease: norethindrone is metabolized by the liver and should be used cautiously in people with liver disease. Liver function tests may need to be monitored during treatment with norethindrone. 
• Cardiovascular disease: norethindrone may increase the risk of stroke or heart attack, particularly in individuals with other risk factors like obesity, smoking, or hypertension. 
• Diabetes: norethindrone may affect blood sugar levels and should be used cautiously in diabetic patients 
• Migraines: norethindrone may trigger or worsen migraines in some individuals. 
• Undiagnosed vaginal bleeding: norethindrone should not be used in individuals with undiagnosed vaginal bleeding. 

Pregnancy / Lactation

Pregnancy consideration:  

Category X 

Breastfeeding warnings:  

The drug is excreted in breast milk; hence use it with caution 

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: No evidence of risk to the fetus is found in animal reproduction studies, and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a human product; Pregnant women must take care of the potential risks. 
• Category D: There is adequate data with sufficient evidence of human fetal risk from various platforms. However, despite potential dangers may be used only in emergencies for potential benefits. 
• Category X: Drugs listed in this category outweigh the risks over benefits. The drug is not for pregnant women. 
• Category N: No data is available for the drug under this category. 

Pharmacology

Pharmacology: 

norethindrone is a synthetic progestin, a synthetic version of the hormone progesterone. Progesterone is a naturally occurring hormone that regulates the menstrual cycle and helps in the preparation of the uterus for pregnancy. 

norethindrone works by binding to progesterone receptors in the body, which prevents the release of (LH) and (FSH) from the pituitary gland. LH and FSH are hormones usually released during the menstrual cycle and play a key role in stimulating the release of an egg from the ovary (ovulation). 

By preventing the release of LH and FSH, norethindrone inhibits ovulation, which means that an egg is not released from the ovary and cannot be fertilized by sperm. In addition, norethindrone thickens the cervical mucus, hampering the sperm from reaching the ovum 

In treating certain gynecological conditions, such as endometriosis, norethindrone is believed to work by suppressing the growth of the endometrial tissue, which can reduce pain and bleeding associated with the condition. 

Pharmacodynamics: 

The pharmacodynamics of norethindrone involves its effects on various hormonal systems in the body, primarily the hypothalamic-pituitary-gonadal (HPG) axis and the endometrium. 

As a synthetic progestin, norethindrone binds to progesterone receptors in the body, which leads to several effects. First, norethindrone inhibits the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. These hormones are essential for the normal functioning of the menstrual cycle and ovulation, so their inhibition prevents ovulation. 

norethindrone also affects the endometrium, which is the lining of the uterus. It suppresses the growth of the endometrial tissue, which can reduce the amount of menstrual bleeding and alleviate pain associated with conditions such as endometriosis. 

Pharmacokinetics: 

Absorption 

The bioavailability is 64% 

A peak serum concentration is achieved in 1-2 hours 

Distribution 

The volume of distribution is 4L/kg 

61% of protein is bound  

Metabolism 

The drug is metabolized in the liver  

Inactive sulfates and glucuronide metabolites are formed 

Elimination and Excretion 

The half-life is 4-13 hours 

The drug is excreted 35-43% in feces and 33-81% in urine 

Adminstartion

Administration: 

norethindrone is available in various administration forms, including oral tablets, injections, and intrauterine devices (IUDs). 

When using oral tablets, the medication is taken at the same time once daily, preferably with food, to decrease the likelihood of stomach upset. It is essential to follow the dosing instructions your healthcare provider provides carefully, as the dosage may vary depending on the reason for use. 

norethindrone injections are given by a healthcare provider once every one to three months, depending on the medication used. The injection is typically administered into the muscle, such as the buttock or upper arm. 

A healthcare provider placed intrauterine devices containing norethindrone in the uterus during an office visit. They can remain in place for several years, depending on the specific type of device used. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: norethindrone 

Pronounced: nor-eth-IN-drone 

Why do we use norethindrone? 

norethindrone is a synthetic form of the hormone progesterone, used in various forms of hormonal birth control. norethindrone is also used to treat several conditions, such as endometriosis, irregular periods, and abnormal uterine bleeding. In these cases, it works by regulating the menstrual cycle and reducing the amount of menstrual bleeding.