What is the dosage and duration of Primalut (norethisterone) 5mg for a female patient of reproductive age to delay her menstrual cycle?

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Norethisterone 5mg Dosing for Menstrual Delay

For delaying menstruation, take norethisterone 5mg orally three times daily (total 15mg/day), starting 3 days before your expected period and continuing until you want menstruation to occur. 1, 2

Dosing Protocol

  • Start timing: Begin exactly 3 days before the expected menstruation 1, 2
  • Dose: 5mg three times daily (morning, afternoon, evening) for a total daily dose of 15mg 2
  • Duration: Continue throughout the entire desired delay period 1
  • Maximum recommended duration: Up to 2 weeks of delay 2
  • Critical timing note: Starting after bleeding has already begun will NOT be effective 2

Success Rates and Effectiveness

  • Women with regular menstrual cycles achieve approximately 87% success rate with this regimen 2
  • The higher dose (15mg daily in divided doses) is necessary for reliable menstrual suppression—lower doses are insufficient 1

Important Safety Considerations

Absolute contraindications (do NOT use if you have): 2

  • Current or history of blood clots (venous thromboembolism)
  • Active liver disease or liver tumors
  • Undiagnosed vaginal bleeding
  • Pregnancy
  • Breast cancer or other hormone-sensitive cancers

Use with caution if you have: 2

  • History of depression
  • Cardiovascular risk factors
  • Migraine with aura (especially if over 35 years old)
  • History of deep vein thrombosis 1
  • Uncontrolled hypertension 1

Critical Counseling Points

  • This is NOT contraception: You must use additional contraceptive methods if sexually active during treatment 1
  • Menstruation timing: Expect your period to begin 2-3 days after stopping norethisterone 3
  • Avoid repeated use: For frequent or prolonged menstrual delay needs, discuss alternative hormonal management options with your provider 1

Common Pitfalls to Avoid

  • Insufficient dosing: Taking only 5mg once or twice daily will likely fail—the full 15mg daily dose (5mg three times daily) is required 1, 2
  • Late initiation: Starting on the day of expected bleeding or after bleeding begins renders treatment ineffective 2
  • Irregular cycles: Women with irregular menstrual cycles have lower success rates and may need alternative approaches 2

References

Guideline

Norethisterone for Delaying Menstruation

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Norethisterone for Menstrual Delay

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Norethisterone treatment to control timing of the IVF cycle.

Human reproduction (Oxford, England), 1986

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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