Hormone replacement therapy: clinical benefits and side-effects

Area of Science:

• Endocrinology
• Pharmacology

Background:

• Current estrogen doses in hormone replacement therapy (HRT) can cause side effects, leading to poor compliance and reduced efficacy.
• Estrogen (E2) levels fluctuate during the menstrual cycle, influencing symptom incidence.
• Optimal E2 levels are suggested to be around 100 pg/ml for managing menopausal symptoms and providing long-term health benefits.

Purpose of the Study:

• To determine optimal plasma estradiol (E2) levels for hormone replacement therapy (HRT).
• To investigate the relationship between E2 levels and the incidence of clinical side effects and symptoms.
• To emphasize the need for individualized dosing strategies in HRT.

Main Methods:

• Review of experimental and human studies on estrogen levels and associated symptoms.
• Analysis of E2 levels during different phases of the menstrual cycle and their correlation with discomfort.
• Consideration of interindividual variations in estrogen clearance rates.

Main Results:

• Mild-follicular phase (E2 60-150 pg/ml) shows lowest cyclic discomfort.
• Mid-luteal phase (E2 up to 150 pg/ml) is associated with pregnancy-like symptoms.
• Perimenstrual phase (E2 below 40 pg/ml) correlates with increased asthenia, mood disturbances, and headaches.
• Plasma E2 around 100 pg/ml appears optimal for treating hot flushes, bone loss, and cardiovascular protection.
• Standardized dosing is unlikely to achieve optimal levels due to variable estrogen clearance.

Conclusions:

• Individual titration of estrogen doses is mandatory for improving HRT compliance and long-term efficacy.
• Objective markers for efficacy are needed, especially for osteoporosis and cardiovascular disease prevention in older postmenopausal women.
• Lower doses and the use of progesterone can reduce side effects associated with HRT, particularly those involving added progestins.