HealthDay News – Combination therapy with 25 mg of amitriptyline and 240 mg of intravenous lidocaine given weekly for 4 weeks did not result in meaningful improvement of fibromyalgia (FM) symptoms at the 8 week time point after treatment initiation, according to a study published online June 16 in the International Journal of Rheumatic Diseases.

Ana Laura Albertoni Giraldes, MD, from the Federal University of São Paulo in Brazil, and colleagues conducted a randomized trial involving patients with FM. Participants were randomized to receive lidocaine in saline solution or saline solution once a week for four weeks. 

High Yield Data Summary

  • Combination therapy of IV lidocaine + amitriptyline resulted in improved FM symptom analgesia at week 2, with no differences at other times assessed during the 8-week evaluation

All patients received amitriptyline for eight weeks. Patients underwent pain assessment, completed the FM impact questionnaire, and had levels of interleukins (IL)-1, 6, and 8 measured before and after treatment.


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The researchers found that the lidocaine group had lower pain intensity at week two of treatment, but not at other time points assessed during eight weeks. 

Both groups experienced a reduction in pain intensity at eight weeks after the start of treatment. There was no difference between the groups in use of acetaminophen and tramadol, or in plasma levels of IL-1, -6, and -8. There was no difference between the groups in clinical manifestations or side effects.

“The use of lidocaine combined with amitriptyline promoted a better analgesic effect [only] at 2 weeks after the beginning of treatment, with no differences at other times assessed during 8 weeks.” the authors write.

Summary and Clinical Applicability

While the addition of lidocaine to amitriptyline promoted a better analgesic effect in patients with FM at the 2 weeks time point, no meaningful improvements were noted at 8 weeks.

Limitations and Disclosures

Since lidocaine was administered in combination with amitriptyline, it was not possible to ascribe the analgesic and antiinflammatory effects of intervention to lidocaine alone. 

“The lack of difference in the analgesic effect may have been because amitriptyline alone promoted a sufficient effect… [or that] lidocaine needs to be administered at smaller intervals to obtain a difference in effect,” the authors mentioned.

Reference

Albertoni AL, Salomão R, Leal PD, Brunialti MK, Sakata RK. Effect of intravenous lidocaine combined with amitriptyline on pain intensity, clinical manifestations and the concentrations of IL-1, IL-6 and IL-8 in patients with fibromyalgia: A randomized double-blind study. Int J Rheum Dis. 2016; doi:10.1111/1756-185X.12904.