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

Abstract OBJECTIVE: To evaluate the effect of the selective estrogen receptor modulator raloxifene hydrochloride (Evista, Eli Lilly and Company, Indianapolis, IN) on plasma levels of beta-endorphin, and to determine whether beta-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 beta-endorphin, climacteric symptom score, and correlation with beta-endorphin levels. RESULT(S): Raloxifene treatment significantly increased levels of beta-endorphin and did not significantly affect climacteric symptoms, with the exception of worsening vasomotor symptoms. No significant relation was seen between plasma levels of beta-endorphin and climacteric symptoms. CONCLUSION(S): Raloxifene modulates plasma levels of beta-endorphin without concomitantly relieving climacteric symptoms, as seen with hormone replacement therapy.