Lidocaine on Manifestations of Fibromyalgia

Background and Objectives: Fibromyalgia is a pain syndrome characterized by numerous manifestations. The objective of this study was to evaluate the effect of the combination of intravenous lidocaine and amitriptyline on the manifestations of fibromyalgia. Methods: A prospective, randomized, double-blind, comparative study was conducted. All patient received 25 mg amitriptyline. Patients of group 1 (n = 15) received 125 mL 0.9% saline, and patients of group 2 (n = 15) received 240 mg lidocaine in 125 mL 0.9% saline once a week for 4 weeks. Manifestations were recorded before and 4 weeks after treatment. Pain intensity was rated on a verbal numerical scale.

Amitriptyline was chosen in the present study because it is the most widely used antidepressant with proven analgesic efficacy for the treatment of a variety of chronic pain syndromes. Amitriptyline also promotes improvement of sleep, an effect observed in the present study. Lidocaine has been widely applied by the intravenous route and patients with a variety of pain syndromes, including fibromyalgia, have reported pain relief with this technique.The dose of lidocaine employed by various investigators ranges from 1 to 5 mg/kg administered over a period of 30-60 min. The minimum effective dose is 1.5 mL/L, which is achieved with 2-5 mg/kg infused over 30-60 min. In these study, 240 mg lidocaine was administered, corresponding to about 3 mg/kg.