Norethisterone
- OralNorethisteroneMicronor, Primolut N
Mechanism of Action
- Thickens cervical mucus, resulting in reduced sperm penetration through the cervix. Less of an effect on follicular development and prevention of ovulation than combined contraceptives.
Pharmacology
- Must be taken at the same time every day, as its mechanism of action relies on its effect on vaginal mucus. If not taken within three hours of the normal time the dose should be skipped and another form of contraception (condoms / diaphragm) should be used for 48 hours.
Clinical Use
- Indications
- Contraception in patients intolerant of combined oral contraceptives
- Contraception in women who are breastfeeding
- Contraindications
- Pregnancy
- Past DVT / PE
- Ischaemic heart disease
- Past stroke / TIA
- Breast cancer within the past five years
- Ischaemic heart disease
- Adverse Effects
- Headache
- Breast pain
- Nausea / vomiting / bdominal pain
- Dizziness
- Depression
- Irregular bleeding
- Acne