What is the dosage and administration of norethindrone (progestin) for treating heavy menstrual bleeding?

Norethindrone 5mg for Heavy Menstrual Bleeding

Direct Recommendation

For heavy menstrual bleeding, norethindrone 5mg should be dosed at 5mg twice daily on days 19-26 of the menstrual cycle (luteal phase dosing), though this regimen is less effective than NSAIDs or the levonorgestrel-releasing IUD and should not be considered first-line therapy. 1, 2

Treatment Hierarchy for Heavy Menstrual Bleeding

Before using norethindrone, understand that superior options exist:

• The levonorgestrel-releasing IUD (LNG-IUD) is the most effective first-line treatment, reducing menstrual blood loss by 71-95% 1
• NSAIDs (5-7 days during menstruation) are the recommended first-line pharmacologic treatment when LNG-IUD is not used 1
• Norethindrone is a second-line option when these treatments fail or are contraindicated 2

Norethindrone Dosing Regimen

Standard dosing for heavy menstrual bleeding:

• 5mg twice daily (total 10mg/day) on days 19-26 of the menstrual cycle 2
• This luteal phase dosing is taken for 8 days per cycle 2
• Treatment should continue for at least 2-3 cycles to assess efficacy 2, 3

Alternative dosing for acute heavy bleeding (adolescents):

• Norethindrone taper regimen can achieve complete cessation of bleeding within 7 days in approximately 79% of cases 4
• This approach is particularly useful when estrogen is contraindicated 4

Expected Efficacy and Limitations

Norethindrone reduces menstrual blood loss but has significant limitations:

• Median reduction from 109mL to 92mL per cycle (approximately 16% reduction) 2
• 52-67% of women remain menorrhagic (>80mL blood loss) after 2 months of treatment 2
• Significantly less effective than danazol regimens for objectively proven menorrhagia 3
• Less effective than NSAIDs in reducing both blood loss volume and duration of bleeding 2

Critical Safety Screening

Before prescribing, exclude these absolute contraindications:

• Pregnancy (must be ruled out in all reproductive-age women) 1
• History of thromboembolism or deep vein thrombosis 5
• Undiagnosed vaginal bleeding 5
• Active liver disease or hepatic dysfunction 6, 5
• Breast cancer or hormone-sensitive malignancies 5
• Uncontrolled hypertension 5
• Cardiovascular disease (cerebrovascular disease, coronary artery disease) 5

Common Pitfalls and Adverse Effects

Anticipate these issues:

• Irregular breakthrough bleeding is the most common reason for discontinuation (54.5% of cases) 4
• Weight gain occurs and resolves after cessation 7
• Heavier withdrawal bleeding compared to combined oral contraceptives 7
• Overall discontinuation rate approaches 48.5% 4

When to Abandon This Approach

If bleeding persists despite 2-3 cycles of norethindrone:

• Counsel on alternative methods and offer different medical options 1
• Consider tranexamic acid if no cardiovascular contraindications exist 1
• Re-evaluate for structural causes (fibroids, polyps, adenomyosis, endometrial pathology) 1
• Consider endometrial ablation as a conservative surgical option 1

Important Counseling Points

Patients must understand:

• Norethindrone at this dose is NOT a contraceptive—additional contraception is required if sexually active 5
• This is not intended for continuous or repeated long-term use 5
• Baseline blood pressure monitoring is required 6
• Multiple drug interactions exist, particularly with antibiotics, anticonvulsants, and St. John's wort 6