When should I start taking Norethindrone (Norethindrone Acetate) 5 MG after my period starts?

When to Start Norethindrone Acetate 5 MG After Period Begins

You can start taking norethindrone acetate 5 mg immediately now that your period has started, but you must use backup contraception (abstinence or barrier method) for the next 2 days if using it for contraception. 1

Timing Guidelines Based on Indication

For Contraception (Progestin-Only Pills)

• Start anytime during days 1-5 of menstrual bleeding - no backup contraception needed if started within the first 5 days 1
• If started after day 5 of bleeding - you need backup contraception (abstinence or barrier method) for 2 days 1
• Take at the same time every day, as progestin-only pills have a narrow window of effectiveness (peak levels at 2 hours, near baseline by 24 hours) 1

For Abnormal Uterine Bleeding or Amenorrhea Treatment

• The FDA label indicates 2.5-10 mg daily for 5-10 days to produce secretory transformation of the endometrium 2
• Withdrawal bleeding typically occurs 3-7 days after stopping the medication 2
• This is not the contraceptive indication, so backup contraception timing doesn't apply here

For Endometriosis Treatment

• Start with 5 mg daily for two weeks, then increase by 2.5 mg every two weeks until reaching 15 mg daily 2
• Continue at 15 mg for 6-9 months or until breakthrough bleeding occurs 2

For Menstrual Delay (Travel/Special Events)

• Start 5 mg three times daily, beginning 3-4 days before expected menstruation 3
• Continue until the desired end date when menstruation can occur 3
• Important: This dose does NOT provide contraception; use additional contraceptive methods if needed 3

Critical Backup Contraception Requirements

The 2-day backup requirement for progestin-only pills is based on the time needed to achieve contraceptive effects on cervical mucus (approximately 48 hours) 1. This is shorter than the 7-day backup period required for combined hormonal contraceptives 1.

Common Pitfalls to Avoid

• Don't confuse progestin-only pills with combined hormonal contraceptives - they have different backup contraception requirements (2 days vs 7 days) 1
• Don't skip doses - progestin-only pills must be taken at approximately the same time daily due to rapid elimination 1
• Don't assume contraceptive protection at higher doses - when using 5 mg three times daily for menstrual delay, this does not provide contraception 3
• Be aware that breakthrough bleeding is common with norethindrone acetate alone (68% in one study), though this can be reduced if preceded by GnRH agonist therapy 4

Contraindications to Verify Before Starting

Ensure you do not have: pregnancy, history of thromboembolism, undiagnosed vaginal bleeding, active liver disease, breast cancer or hormone-sensitive cancers, uncontrolled hypertension, or cerebrovascular/coronary artery disease 1, 3