Raloxifene treatment increases plasma levels of beta-endorphin in postmenopausal women: a randomized,placebo-controlled study

Objective: To evaluate the effect of the selective estrogen receptor modulator raloxifene hydrochloride (Evista, Eli Lilly and Company, Indianapolis, IN) on plasma levels of β-endorphin, and to determine whether β-endorphin levels and menopausal symptoms are related.

Design: A randomized, double-blind, placebo-controlled pilot study.

Setting: Endocrinology outpatient department.

Patient(s): Forty postmenopausal women.

Intervention(s): The women received raloxifene, 60 mg/d, or placebo for 3 months. A questionnaire on climacteric symptoms was administered before and after treatment.

Main Outcome Measure(s): Circulating levels of β-endorphin, climacteric symptom score, and correlation with β-endorphin levels.

Result(s): Raloxifene treatment significantly increased levels of β-endorphin and did not significantly affect climacteric symptoms, with the exception of worsening vasomotor symptoms. No significant relation was seen between plasma levels of β-endorphin and climacteric symptoms.

Conclusion(s): Raloxifene modulates plasma levels of β-endorphin without concomitantly relieving climacteric symptoms, as seen with hormone replacement therapy.