Mirtazapine, an atypical antidepressant exhibits minimal effects in alleviating symptoms of fibromyalgia, as per recent systematic analysis published in the journal, Cochrane Database of Systematic Reviews.

Fibromyalgia is a chronic condition represented by fatigue; sleep disturbance, widespread pain and cognitive dysfunction. The treatment of fibromyalgia on time is very pivotal.

Patrick Welsch and colleagues tested the contribution of an antidepressant, Mirtazapine as compared to other active drug or placebo in managing fibromyalgia among adults. The RCTs (randomized controlled trials) with comparative information regarding Mirtazapine against other drug or placebo were identified by searching MEDLINE, Embase, CENTRAL, WHO, SCOPUS, International clinical trials registry platform and US national institutes of health for ongoing and published trials along with investigated reference list of selected articles till 9 July 2018.  The efficacy, safety and tolerability; extraction of study characteristics; assessment of the risk of bias; examination of issues related to study quality and discussion on resolving discrepancies were independently analyzed by two review authors. The PGIC (Patient Global Impression of Change), participant-reported pain relief, tolerability and safety were considered as primary outcomes.  Fatigue, mean pain intensity, sleep issues, particular adverse effects, negative mood and health-related quality of life (HRQoL) improved by 20 %, or more were the secondary outcomes analyzed during the trial. The standardized mean difference (SMD), numbers needed to treat (NNT) and risk difference (RD) was determined by using the random-effects model. The GRADE was used to assess evidence and create a 'Summary of findings' table.

A total of 3 studies (606 patients) involved the Mirtazapine and placebo comparison. Two studies showed the high risk of bias. The outcomes were of Low or very low-quality due to the risk of publication bias, poor study quality, imprecision and the low number of events. Mirtazapine and placebo exhibited no difference for the primary outcome. However, some of the secondary outcomes showed a clinically-relevant benefit via Mirtazapine as compared to placebo such as sleep issues, mean pain intensity and pain relief of 30% or higher. No difference was seen related to adverse events between both groups. Mirtazapine showed clinically relevant side effects like weight gain, increased alanine aminotransferase and somnolence as compared to placebo.

As per outcomes, Mirtazapine exhibited positive effects but only for pain relief of 30% not for 50% or higher with specific side effects. This reflects very low-quality efficacy and safety of Mirtazapine in fibromyalgia treatment.