mestranol + norethisterone: clinical use

Prescribing considerations

• Confirm pregnancy status and assess personal and family thrombotic and arterial cardiovascular risk.
• Review smoking, migraine, blood pressure, body weight, planned surgery or immobilisation, liver disease, depression and interacting medicines.
• The selected Norinyl-1 product is listed as discontinued, so verify availability and select an appropriate current alternative where required.

Contraindications and cautions

• Current pregnancy or hypersensitivity to an ingredient
• Current or previous venous thromboembolism, significant thrombophilia or major thrombotic risk
• Arterial thrombotic disease, including stroke, coronary disease, myocardial infarction or angina
• Classical focal or progressively worsening migraine
• Acute or severe chronic liver disease or liver tumour
• Known or suspected breast, genital or other oestrogen-dependent malignancy
• Unexplained vaginal bleeding
• Specified interacting hepatitis C antiviral combinations

Monitoring

• Measure blood pressure before prescribing and periodically thereafter.
• Review new migraine, visual disturbance, persistent severe headache, thrombotic symptoms, mood deterioration or liver dysfunction promptly.
• Reassess cardiovascular and venous-thromboembolism risk when health circumstances or medicines change.

Clinical pharmacology

A fixed oestrogen–progestogen combination. Mestranol undergoes hepatic demethylation to ethinylestradiol; combined effects suppress gonadotropins and ovulation and alter cervical mucus and endometrium.

Formulation and product differences

• Norinyl-1 is a white oral tablet supplied in day-marked blister strips.
• The formulation contains lactose, maize starch, polyvidone and magnesium stearate.
• The selected product is listed as discontinued on eMC.