Effect of Intravenous Lidocaine Associated With Amitriptyline on Pain Relief and Plasma Serotonin, Norepinephrine, and Dopamine Concentrations in Fibromyalgia

The Clinical Journal of Pain, 04/19/2011

Combined administration of 240 mg intravenous lidocaine (once a week) and 25 mg amitriptyline for 4 weeks did not modify pain intensity or plasma serotonin, norepinephrine, or dopamine concentrations in fibromyalgia patients.


  • A prospective, randomized, double–blind comparative study was conducted in 30 patients
  • All patients received 25 mg amitriptyline; monotherapy group (n=15) received 125 mL saline, and combined therapy group (n=15) received 240 mg lidocaine in 125 mL saline once a week for 4 weeks
  • Serotonin, norepinephrine, and dopamine were measured in plasma at time zero (T0) and after 4 weeks (T4)
  • Pain intensity was rated on a numerical scale at the beginning of the study and weekly for 4 weeks


  • All patients were females and the mean age was 44.7±10.5 years for monotherapy group and 40.9±11.6 years for combined therapy group
  • No difference in pain intensity at baseline was observed between groups, with a decrease after treatment in monotherapy group (T0: 7.0±1.2 and T4: 4.0±2.1) and in combined therapy group (T0: 7.6±0.8 and T4: 4.1±2.3)
  • Plasma serotonin and norepinephrine levels were similar in the 2 groups at T0 and T4
  • An increase in dopamine levels was observed in monotherapy group from the beginning to the end of treatment

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