Placebo-controlled cross-over study of effects of tibolone on premenstrualsymptoms and peripheral beta-endorphin concentrations in premenstrual syndrome

Central nervous system hormones have been linked to premenstrual syndrome ( PMS) and beta-endorphin (beta-EP) is thought to be involved in the pathophy siology. We have tested the efficacy of the synthetic steroid Org OD 14 (ti bolone) in the treatment of PMS, This prospective, randomized, placebo-cont rolled, double-blind cross-over study included 18 ovulatory women with PMS as ascertained by a visual linear analogue scale (VLAS), The women in each group received either 2.5 mg per day Org OD 14 (n = 9) or a multi-vitamin p ill as placebo (n = 9) for 3 months. Treatments were then crossed over to a placebo for a further 3 months, VLAS ratings were evaluated at the end of each menstrual cycle throughout the study. Peripheral beta-EP concentration s were determined by radioimmunoassay on days 7 and 25 of each menstrual cy cle. Changes in VLAS score and beta-EP concentrations from baseline were ca lculated and analysed by Student's paired t-test, Improvements in VLAS scor es and beta-EP concentrations were evident during the second and third mont hs of tibolone treatment. At the end of the third month, there was a signif icant improvement in VLAS scores of all symptom categories compared with pr etreatment and placebo during treatment with tibolone (P < 0.05), Similar r esults were obtained in the first placebo group when switched to tibolone, beta-EP concentrations were not significantly different between the study g roups at the initial cycle (15.9 +/- 3.6 versus 17.2 +/- 2.3 pg/ml), The in crease in beta-EP concentration was significantly greater on day 25 of the menstrual cycle in women treated with tibolone compared with baseline and p lacebo group (22.5 +/- 4.4 versus 15.9 +/- 3.6 and 17.2 +/- 2.3 pg/ml respe ctively, P < 0.05). Our data confirm the clinical efficacy of tibolone in P MS-related symptoms, as well as its effects on serum beta-EP concentrations in patients with PMS.