Hormone Replacement Therapy Dosing for Hot Flushes
For hot flushes, HRT should be prescribed at the lowest effective dose for the shortest duration possible, typically starting with 1 mg daily oral estradiol or 50 μg/24 hours transdermal estradiol, with dose adjustments based on symptom control. 1, 2, 3
Initial Dosing Recommendations
Estrogen Component:
- Oral estradiol: Start at 1 mg daily, range 1-2 mg daily 2
- Transdermal estradiol: Start at 50 μg/24 hours, range 50-100 μg/24 hours 1, 3
Progestin Component (for women with intact uterus):
- Sequential regimen: 10 mg norethisterone orally for 12-14 days per 28-day cycle 1
- Continuous regimen: 1 mg norethisterone orally daily 1
- Alternative: Micronized progesterone is preferred due to lower rates of venous thromboembolism and breast cancer risk 4
Route of Administration Considerations
Transdermal estrogen formulations are preferred over oral formulations due to:
- Lower rates of venous thromboembolism (VTE) 4
- Lower risk of stroke 4
- Minimal effect on lipid metabolism (beneficial for women with hypertriglyceridemia) 5
Dose Adjustment Protocol
- Start with the lowest effective dose
- Assess symptom control after 3 months
- If symptoms persist, increase dose incrementally
- Maximum dose for menopausal symptoms: 2-4 mg daily oral estradiol or 100-200 μg/24 hours transdermal estradiol 1
- Attempt to taper or discontinue medication at 3-6 month intervals 2, 3
Special Considerations
Cancer History
- HRT is contraindicated in survivors with hormonally mediated cancers 4
- For breast cancer survivors, non-hormonal alternatives should be considered first 4, 1
Thrombotic Risk
- For patients with high thrombotic risk, transdermal estrogen is preferred 1
- Micronized progesterone is preferred over medroxyprogesterone acetate (MPA) due to lower VTE risk 4
Efficacy Expectations
- Estrogen is effective in over 80% of cases for hot flushes 6
- Low-dose HRT (25 μg/day transdermally or 0.3 mg/day orally) can reduce vasomotor symptoms by up to 86% compared to 55% with placebo 7
Monitoring and Follow-up
- Clinical review every 3-6 months initially, then annually 1
- Assess symptom control, side effects, and compliance
- For women with a uterus, endometrial sampling should be performed if abnormal vaginal bleeding occurs 2, 3
Important Caveats
- Use HRT for the shortest duration consistent with treatment goals and risks 2, 3
- Combined estrogen/progestogen therapy increases breast cancer risk when used for more than 3-5 years 8
- Low-dose HRT may improve compliance rates and potentially reduce side effects 5, 7
- Custom compounded bioidentical hormones are not recommended due to lack of data supporting safety and efficacy claims 4
HRT remains the most effective treatment for hot flushes, but the decision to use it should be based on a thorough evaluation of individual risks and benefits, with careful consideration of contraindications and appropriate dose selection.