ethinylestradiol + norethisterone: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
ethinylestradiol + norethisterone: clinical details
Prescribing considerations
- Assess thromboembolic and family history, smoking, age, obesity, cardiovascular risk, migraine, medicines and postpartum status.
- Explain thromboembolic risk and warning symptoms.
- Consider planned major surgery or prolonged immobilisation.
- Promptly review new migraine, visual symptoms, significant mood change or relevant new conditions.
Contraindications and cautions
- Current or previous venous thromboembolism, relevant thrombophilia or significant thrombotic risk factors
- Arterial thrombotic disease, including stroke, coronary disease, myocardial infarction or angina
- Focal or escalating migraine history
- Acute or severe chronic liver disease or liver tumour
- Known or suspected breast, genital or other oestrogen-dependent malignancy
- Unexplained vaginal bleeding
- Pregnancy
- Concomitant use with specified hepatitis C antiviral combinations
Monitoring
- Record blood pressure before initiation and reassess regularly.
- Review thrombotic and cardiovascular risks, smoking, migraine, mood and interacting medicines.
- Investigate persistent or concerning bleeding changes and assess pregnancy where indicated.
- Be aware of possible changes to some liver, thyroid, lipid, coagulation and carrier-protein laboratory results.
Clinical pharmacology
Ethinylestradiol and norethisterone suppress gonadotropin activity and inhibit ovulation, with additional effects on cervical mucus and the endometrium. Both undergo gastrointestinal absorption and hepatic metabolism.
Formulation and product differences
- The selected Brevinor presentation is a fixed-combination blue oral tablet containing lactose.
- Other products may use different strengths or phasic arrangements; consult the relevant product information.
ethinylestradiol + norethisterone preparations and strengths
Tablet
Route: Oral
Strengths: 1 mg + 0.035 mg
ethinylestradiol + norethisterone interactions
Tell the prescriber or pharmacist about all medicines and herbal products because some combinations reduce contraceptive effectiveness or increase other risks.
St John’s wort
May reduce hormone exposure and contraceptive effectiveness; concurrent use should be avoided.
Enzyme-inducing antiseizure medicines, including carbamazepine, phenytoin, phenobarbital, primidone, oxcarbazepine and topiramate
Can accelerate hormone metabolism and reduce contraceptive protection, requiring specialist contraception advice.
Rifampicin, rifabutin, some HIV medicines, griseofulvin and modafinil
May reduce contraceptive effectiveness; an alternative or additional method may be required.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.