Effect of vitamin B12 on the symptom severity and psychological profile of fibromyalgia patients; a prospective pre-post study

Abstract Background Fibromyalgia (FM) as a prototypical nociplastic pain condition displays a difficult therapeutic situation in many cases. Given the promising data on the effect of vitamin B12 in improving pain and cognitive functions in various nociplastic pain conditions, we aimed to determine the efficacy of 1000 mcg daily dose of oral vitamin B12 on the symptom severity and psychological profile of FM patients. Methods This open-label, pre-post study was performed on FM patients whose diagnoses were confirmed by a rheumatologist based on the 2016 American College of Rheumatology (ACR). Patients were instructed to take a daily dose of 1000mcg vitamin B12 for fifty days. Outcome measures including the Revised Fibromyalgia Impact Questionnaire (FIQR), Hospital Anxiety and Depression Scale (HADS), 12-item Short-Form health survey (SF-12), and pain Visual Analog Scale (pain-VAS) were fulfilled by patients before and after the treatment. Results Of 30 eligible patients, 28 patients completed the study protocol. Patients were female with a mean age of 47.50 ± 8.47 years. FIQR scores in all domains improved significantly after treatment (total FIQR: 49.8 ± 21.86 vs 40.00 ± 18.36, p value