Comparison of Ketamine and Esketamine in Patients Suffering From Fibromyalgia Syndrome

Randomised, triple-blind crossover comparing intravenous ketamine (0.3 mg/kg) and intravenous esketamine (0.15 mg/kg) in patients with fibromyalgia; each patient receives two 1-hour infusions of each drug separated by 6 weeks with a 1-week washout.

Primary outcome is change on the Fibromyalgia Impact Questionnaire (FIQ); safety and adverse effects monitored acutely during and after infusions and at follow-up.