Lidocaine Infusion Decreases Pain Scores in a Fibromyalgia Pain Population with Signifi cant Differential Pain Relief Secondary to Smoking Status

Study Objective: Our hypothesis is that systemic lidocaine can signifi cantly reduce chronic pain associated with fi bromyalgia.A secondary goal of the study is to determine if other patient demographics can affect the response to IV lidocaine. Design: Retrospective chart review Setting: Outpatient pain clinicPatients: 55 patients being treated for fi bromyalgia by lidocaine infusion Interventions: Intravenous infusion of lidocaine 5mg/kg over 1 hourMeasurements: Two-tailed paired t-tests (α=0.05) were performed to test for signifi cant change from pre-to post-infusion in BPI, PI, and VAS scores.Smoking status and race classifi cation were also identifi ed. Main Results:Mean BPI score decreased from 83.2±16.5 to 73.7±21.6 after infusion of 4 to 5 mg/ kg of lidocaine in 500 ml 5% dextrose (p-value<0.0001).Mean VAS decreased from 7.6±1.6 to 5.8±2.2(p<0.0001).The post-infusion BPI was signifi cantly lower in non-smokers 68.5 ±19.6 vs. smokers 80.3 ±17.2 (p=0.028) and Caucasians 69.3 ±20.3 vs. African-Americans 83.6±21.4(p=0.027).Conclusions: A retrospective analysis of 55 fi bromyalgia patients who received IV lidocaine shows a statistically signifi cant decrease in pain scores.A subgroup analysis shows that baseline pain scores are higher in smokers, and response to IV lidocaine is attenuated in smokers compared to non-smokers.