Effects of Intravenous Lidocaine on Rheumatoid Arthritis in Preclinical Rat Model and Clinical Trial

Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation and pain. Lidocaine has anti-inflammation and pain-relieving properties. This study intends to evaluate the effects of lidocaine on RA in a preclinical rat model and a clinical trial.

Rats with adjuvant-induced arthritis (AIA) received intravenous lidocaine or no treatment. Pain behavior parameters and arthritis index (AI) were assessed. Synovial tissue lesions, the number of M1 macrophages and gene expression of inflammatory molecules: IKKα, NF-κB p65, IL-1β and TNF-α were profiled by immunohistochemical staining or quantitative PCR. In clinical trial, RA patients (n=40) were assigned into two groups: control group received conventional treatments, lidocaine group: received conventional treatment and intravenous lidocaine for 5 days. Visual analogue scale score (VAS), disease activity score 28 (DAS28) and temperature in painful joint area were recorded.

Lidocaine-treated rats had significantly lower pain parameters, synovial pathology and AI scores, M1 macrophages and gene expressions of inflammatory molecules in synovial tissues on day 28 post modeling compared to AIA rats without the treatment. In a clinical trial, patients who received intravenous lidocaine had similar VAS, DAS28 and SDAI scores in comparison with patients without the treatment. However, lidocaine-treated patients had significantly lower temperatures in the painful joint areas and dosages of glucocorticoids and nonsteroidal anti-inflammatory drugs during the treatment period, compared to patients without intravenous lidocaine.

Intravenous lidocaine attenuated joint pain and synovial inflammation in preclinical AIA rat model and provided adjunctive beneficial effects for the treatment of RA patients.