The Effect of Intravenous Lidocaine Treatment on Sleep and Quality of Life in Fibromyalgia: An Observational Study

Background/Objectives: Fibromyalgia is a painful syndrome with biopsychosocial components that predominantly affects middle-aged women. This study aimed to evaluate changes in sleep quality and quality of life following intravenous (IV) lidocaine treatment in patients with fibromyalgia (FM). Methods: This retrospective observational study included patients diagnosed with fibromyalgia who underwent intravenous lidocaine treatment at a tertiary pain clinic between June 2023 and June 2024 and had a Pittsburgh Sleep Quality Index (PSQI) score > 5. The patients’ demographic data, Fibromyalgia Impact Questionnaire (FIQ) scores at baseline and at 1 and 3 months post-treatment, Numerical Rating Scale (NRS-11) scores, Short Form-12 (SF-12) mental and physical component scores (MCS-12, PCS-12), and PSQI scores were recorded. Results: Overall, 51 patients were included. 92.2% of the patients were women, with a mean age of 41.6 ± 9.5 years. Statistically significant reductions in NRS-11, FIQ, and PSQI scores and increases in SF-12 component scores were observed at 1 and 3 months compared with baseline (p < 0.001). Negative correlations were found between NRS-11 and PCS-12 and MCS-12, and a positive correlation was found between FIQ and PSQI. Sleep quality showed a marked improvement at 1 month; however, attenuation of this benefit was observed at the 3-month follow-up. Conclusions: Sleep quality appeared to be associated with short-term functional outcomes, whereas pain intensity was associated with mid-term clinical status in patients with fibromyalgia. Prospective randomized controlled trials are required to confirm these findings and to determine optimal dosing and treatment schedules.