Transitioning from Oral Estrogen to Transdermal Estrogen Patch
The recommended approach for switching from oral estrogen to a transdermal estrogen patch is to discontinue oral estrogen and immediately start with a transdermal patch delivering 50-100 μg of 17β-estradiol daily, applied to dry, intact skin of the back, abdomen, upper thighs, or upper arms. 1, 2
Dosing Recommendations
- Start with a transdermal patch releasing 50-100 μg of 17β-estradiol per 24 hours, which provides physiological estrogen levels while avoiding first-pass hepatic metabolism 1, 3
- Patches are typically changed twice weekly or weekly depending on the specific product 4
- Peak estradiol levels occur approximately 6-8 hours after patch application 2
- Estradiol levels return to baseline within 8-24 hours after patch removal 4
Application Instructions
- Apply to clean, dry, intact skin on the lower abdomen, upper buttocks, back, or upper arms 2
- Avoid areas with excessive hair, oily skin, irritation, or that are subject to friction from clothing 2, 5
- Rotate application sites to prevent skin irritation 5
- Do not apply to breasts or waistline 5
Advantages of Transdermal Delivery
- Avoids first-pass hepatic metabolism, allowing for lower doses while maintaining therapeutic levels 3, 5
- Provides more stable hormone levels compared to oral administration 2, 3
- Associated with lower risk of venous thromboembolism compared to oral estrogen 1
- May have less negative impact on lipid metabolism 1
- Allows for rapid termination of effect if needed 5
Progestogen Considerations
- For women with an intact uterus, progestogen must be added for endometrial protection 1, 6
- First choice: Micronized progesterone 200 mg daily for 12-14 days per month 1, 6
- Alternative options: Medroxyprogesterone acetate 10 mg daily or dydrogesterone 10 mg daily for 12-14 days per month 1, 6
- Combined patches containing both estrogen and progestin are available in some countries 1
Monitoring and Follow-up
- Evaluate treatment effect after 3-6 months 2
- Annual clinical review is recommended, with particular attention to compliance 1
- No routine laboratory monitoring is required but may be prompted by specific symptoms or concerns 1, 6
Common Side Effects and Management
- Local skin irritation is the most common adverse effect (erythema, pruritus) 3, 7
- If skin irritation occurs, rotate application sites or consider alternative transdermal formulations like gels or sprays 7
- Systemic estrogenic effects appear comparable to oral therapy 3
Special Considerations
- For women with contraindications to transdermal delivery (e.g., extensive skin disorders), oral 17β-estradiol (1-2 mg daily) can be considered as an alternative 1
- For women requiring contraception, 17β-estradiol-based combined oral contraceptives may be preferred over patches 1
- Transdermal estrogen patches may worsen urinary incontinence in some women 1