Continuous Norethindrone Dosing for Endometrial Protection

Dosing Guidelines

The minimum effective dose of norethindrone for endometrial protection with estrogen replacement is 1 mg daily, taken continuously without interruption, as recommended by guidelines based on evidence from Blood Reviews 1
Continuous combined regimens require a minimum of 1 mg of oral norethisterone daily when administered with transdermal or oral estradiol, providing adequate endometrial protection while avoiding withdrawal bleeding 1
Sequential regimens can use 10 mg daily for 12-14 days every 28 days when combined with continuous estrogen, although this may allow for withdrawal bleeding 1

Pregnancy status is a Category X contraindication, and blood pressure measurement and history of breast cancer are important considerations before initiating therapy, as outlined in guidelines from Praxis Medical Insights 2
Annual clinical review is recommended for stable patients, with more frequent monitoring during initial therapy, and liver function tests should be monitored periodically, especially at doses ≥10 mg daily 2
Blood pressure monitoring is necessary at each visit to ensure patient safety 2

Norethindrone is listed as a second-choice progestin after micronized progesterone for hormone replacement therapy, particularly in young women with premature ovarian insufficiency, due to its higher cardiovascular and thrombotic risk compared to micronized progesterone 1
The 1 mg continuous dose of norethindrone effectively prevents endometrial hyperplasia while minimizing side effects, making it a viable option for patients requiring endometrial protection 1
It is crucial to avoid confusing norethindrone with norethindrone acetate, as norethindrone acetate requires lower doses for endometrial protection due to its higher potency 1