Vitex agnus-castus in premenstrual syndrome: A meta-analysis of double-blind randomised controlled trials

Although chasteberry (Vitex agnus-castus, VAC) has been studied in several clinical trials and available as medicine for the alleviation of premenstrual syndrome (PMS) symptoms, the efficacy of properly characterised preparations has not been assessed in meta-analyses. The aim of our work was to evaluate the efficacy of VAC in PMS. The meta-analysis was performed following the PRISMA guidelines using the PICOS format, taking into account the CONSORT recommendations. PubMed, Embase, the Cochrane Central Register of Controlled Trials and Web of Science were searched for studies on VAC. The analysis assessed the efficacy of properly characterised products VAC compared to a placebo for the alleviation of PMS symptoms in terms of responder rate, considering the decrease of Total Symptom Score or PMS Diary score. The random effects model was used to calculate summary relative risk (RR) and 95% confidence interval (CI). Only those randomised, double-blind, placebo-controlled trials were included that fulfilled the criteria of the CONSORT recommendations aiming at the proper characterization of herbal products. Out of the 21 clinical trials, three studies (520 females) fulfilled the inclusion criteria, comparing the efficacy of special extracts Ze 440 and BNO 1095 to a placebo for the treatment of PMS. VAC preparations were confirmed to be effective in the reduction of PMS symptoms: women taking VAC were 2.57 (95% CI 1.52-4.35) times more likely to experience a remission in their symptoms compared to those taking the placebo. Although several clinical trials have been carried out with VAC, the majority of the studies cannot be used as evidence for efficacy due to incomplete reporting, especially concerning the description of the used medication. More trials following the CONSORT recommendations are needed to assess the efficacy of VAC extracts.