Norethisterone

Registered South African indications:

• Contraception

Contraindications

• Hypersensitivity to the active substance or to any of the excipients
• Known or suspected pregnancy
• Venous thromboembolic disorders or history thereof
• Arterial and cardiovascular disease present or in history (e.g., myocardial infarction, cerebrovascular accident, ischaemic heart disease)
• Uncontrolled hypertension
• Acute hepatic disease or history of severe hepatic disease as long as liver function values have not returned to normal
• Primary biliary cirrhosis, Dubin-Johnson syndrome, Rotor syndrome
• Presence or history of liver tumours (benign or malignant)
• History of idiopathic jaundice of pregnancy or severe pruritus of pregnancy
• Known or suspected sex-steroid influenced malignancies (e.g., of the genital organs or the breast)
• Diabetes mellitus with vascular involvement
• Disturbances of lipometabolism
• Undiagnosed vaginal bleeding
• Porphyria

Cautions

• Breastfeeding
• History of thromboembolic disease
• History of diseases that are prone to worsen during pregnancy
• Risk factors for or current diabetes mellitus
• Rapid IM injection
• History of severe depression

Forms avail. in SA and covered in this monograph: inj

Contraception

• IM: 200mg, 8 weekly

Initiate within the first 5 days of the menstrual cycle (1st day of menstruation = 1st day of cycle)

No additional contraceptive cover needed if initiated as above

Inject slowly, deep into the gluteal muscles

If, when the second injection is due, bleeding has not occurred in the preceding 8 weeks the 2nd injection should not be given until pregnancy has been ruled out

See additional prescribing points

Not indicated for use in premenarchal children

Pregnancy

• Contraindicated
• Norethisterone is contraindicated in pregnancy. Like all nortestosterone derivatives used for contraception, norethisterone has slight androgenic activity, and a virilising effect on the external genitalia of a female foetus exposed to norethisterone after the first month of pregnancy cannot be totally ruled out on theoretical grounds. However, no such virilisation has been observed after the few pregnancies that have been reported during the use of norethisterone

Breastfeeding

• Caution
• There appear to be no adverse effects on infant growth or development when using norethisterone after six weeks postpartum. Norethisterone does not appear to affect the quantity or quality of breast milk, however, minute amounts of the active substance are excreted with the milk and although considered harmless to a healthy neonate, might theoretically, like other steroids, impair the degradation of bilirubin, especially during the first week of life. If the mother has received norethisterone, breastfeeding should, therefore, be withheld from neonates with severe or persistent jaundice requiring medical treatment

Renal Impairment

• No dose adjustment recommended

Hepatic Impairment

• Contraindicated
  Acute hepatic disease or history of severe hepatic disease as long as liver function values have not returned to normal

Elderly

• Not indicated for use in geriatric patients

Porphyria Information

• Contraindicated

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Depressed mood
• Dizziness
• Headache

Gastrointestinal Disorders

• Nausea

Genitourinary Disorders

• Uterine/vaginal bleeding including spotting
• Amenorrhoea

Endocrine and Metabolic Disorders

• Increased weight 
• Breast discomfort
• Bloating

Skin and Subcutaneous Tissue Disorders

• Injection site reaction
• Local skin reaction

Immune, Blood and Lymphatic System Disorders

• Hypersensitivity reaction

• CYP3A4 inducers
• Antibiotics
• Antidiabetic agents
• Ciclosporin

• Gynaecological examination
• Blood pressure
• Pregnancy test

Specific cases may require

• Cervical cytology
• Breast examination
• Serum glucose 
• Lipid profile

Changing from different contraceptive methods

• Changing from a combined oral contraceptive: Start with norethisterone immediately on the day after the last active tablet of combined oral contraceptive
• Changing from a progestogen-only method: Switch any day from the minipill without break; from an implant or an intrauterine system on the day of its removal; from another injectable when the next injection would be due. In all of these cases additional use of a barrier method for the first 7 days after injection is advised

Initiating in special circumstances

• Following abortion or delivery: Norethisterone may be started immediately after delivery or abortion

Norethisterone has progestational actions similar to those of progesterone, but is a more potent inhibitor of ovulation and has weak oestrogenic and androgenic properties. It has an inhibitory effect on the secretion of gonadotropins in the anterior lobe of the pituitary, thereby preventing ovulation. Norethisterone also has a styptic effect: a local influence on the endometrium leads to the cessation of dysfunctional bleeding.

Injection (per ml) 200mg

• Nur-Isterate (Bayer) originator

Also available in the following form: Tablet.