Ramosetron as an add-on therapy for refractory fibromyalgia: a randomized, double-blind, placebo-controlled trial

Objective: This study aimed to assess the efficacy and safety of intravenous ramosetron for pain relief in patients with fibromyalgia (FM) unresponsive to conventional treatments. Methods: In this prospective, double-blind, placebo-controlled trial, 80 FM patients were randomly allocated to receive either placebo (n = 40) or ramosetron (n = 40) at a dosage of 0.3 mg/day intravenously for five consecutive days. The primary outcome was the reduction in pain intensity at the end of the treatment period, evaluated using a visual analogue scale (VAS). Secondary outcome measures included the FM Impact Questionnaire, Beck Depression Inventory (BDI), Multi-Dimensional Health Assessment Questionnaire (MDHAQ), EQ-5D and State-Trait Anxiety Inventory on days 5 (end of treatment), 7, 10 and 28. Safety was continuously monitored throughout the study. Results: At the end of the treatment phase, the ramosetron group demonstrated a significantly greater reduction in VAS pain scores compared with the placebo group (1.18 +/- 1.60 vs 0.54 +/- 1.59, P < 0.05). Additionally, the ramosetron group exhibited significant improvements in BDI (4.42 +/- 5.18 vs 1.33 +/- 4.87, P < 0.05) and MDHAQ pain scale (0.37 +/- 0.74 vs 0.04 +/- 0.52, P < 0.05) scores. However, these improvements in pain VAS and BDI scores were not sustained through day 28. The safety profile of ramosetron was favorable, with gastrointestinal symptoms, particularly constipation, being the most commonly reported adverse events. Conclusions: Intravenous administration of ramosetron provided safe and effective short-term relief of pain intensity in FM patients with inadequate response to standard treatments.