From the Guidelines
Norethindrone should be taken at the same time every day without breaks between packs for effective contraception, with a standard dose of 0.35 mg daily, and if a pill is missed by more than 3 hours, it should be taken as soon as possible and backup contraception used for 2 consecutive days. According to the most recent guidelines 1, norethindrone or norgestrel progestin-only pills (POP) can be started at any time, and if it has been more than 5 days after menses started, abstain from sexual intercourse or use barrier methods for 2 days. The key to effective contraception with norethindrone is consistency and taking the pill at the same time daily, as peak serum steroid levels are reached about 2 hours after administration, followed by rapid distribution and elimination 1.
Some key points to consider when taking norethindrone for contraception include:
- Take one pill daily at the same time every day
- If a pill is missed by more than 3 hours, take it as soon as possible and use backup contraception for 2 consecutive days
- Use backup contraception (like condoms) for 2 days if starting the pill more than 5 days after menses started
- Norethindrone works primarily by thickening cervical mucus to prevent sperm from reaching an egg and may sometimes prevent ovulation
- It is suitable for breastfeeding women or those who cannot take estrogen, but may have side effects such as irregular bleeding, headaches, and breast tenderness. The effectiveness of norethindrone is approximately 96% with perfect use but about 91% with typical use, as noted in previous studies 1. However, the most recent guidelines 1 provide the best approach for maximizing effectiveness and minimizing risks.
From the FDA Drug Label
To achieve maximum contraceptive effectiveness, norethindrone tablets must be taken exactly as directed. One tablet is taken every day, at the same time. Administration is continuous, with no interruption between pill packs. The proper instruction to take norethindrone for contraception is to take one tablet every day at the same time, with no interruption between pill packs, as directed 2.
- Take one tablet daily
- Take at the same time every day
- Continuous administration with no interruption between pill packs
From the Research
Proper Instruction for Taking Norethindrone for Contraception
- The proper instruction for taking norethindrone for contraception is to take 0.35 mg daily without interruption 3.
- This regimen was used by 168 women for 4,264 months over a five-year span, resulting in a drug-effectiveness rate of 1.9 and a use-effectiveness rate of 2.5 per 100 woman-years 3.
- However, it is essential to note that norethindrone can be used in combination with other hormones, such as ethinyl estradiol, for contraception 4.
- A 24-day regimen of norethindrone acetate 1 mg/ethinyl estradiol 20 micro g (NETA/EE-24) was found to be effective and well-tolerated, with a cumulative risk of pregnancy of 0.9% during six cycles of treatment 4.
Comparison with Other Contraceptive Methods
- The levonorgestrel-releasing intrauterine system (LNG IUS) is a highly effective and reversible form of contraception, with a pearl index of 0.18 per 100 women-years 5.
- The LNG IUS is also used for the treatment of heavy menstrual bleeding and has been found to be more effective than oral medical therapy in reducing menstrual blood loss 6.
- However, the LNG IUS is not directly related to the use of norethindrone for contraception, and its effectiveness and safety profile may differ from that of norethindrone 5, 6, 7.