Abstract text (incl. figure legends and references)

Question: Trigeminal neuralgia (TN) is a chronic neuropathic pain disorder. Some patients experience severe acute exacerbations, often requiring therapeutic escalation. The efficacy of intravenous (IV) lidocaine infusions in this setting was reported in few small studies, however, there is not a uniform protocol of administration. Our aim was to evaluate the efficacy of IV lidocaine infusion for TN acute exacerbations based on a predefined protocol in a Chronic Pain Outpatient Clinic.

Methods: We included all adult patients admitted to our Outpatient Clinic for treatment of acute exacerbation of TN with IV lidocaine. IV lidocaine (1mg/kg) was infused over 60 minutes in each session. Vital signs were measured during and after each infusion. Pain was evaluated before initiating treatment and after the last infusion using the Numeric Pain Scale (NPS), the Pain Catastrophizing Scale (PCS), the Pain Disability Index (PDI) and the Hospital Anxiety and Depression Scale (HADS). Patient scores were compared using the paired-samples t-test and Wilcoxon. P-values <0.05 were considered statistically significant.

Results: Eight patients completed 12 sessions (3/week), 5 (62.5%) female, with a mean age of 61 ± 14 years. Significant differences were found between baseline and the end of the IV lidocaine treatment in NPS (before 9 ± 5 vs after 4.13 ± 2.42, p=0.02). No significant differences were found in PCS (40.88 ± 9.08 vs 38.88 ± 6.79, p=0.41), PDI (45 ± 24 vs 30.88 ± 22.71, p=0.40) and HADS (anxiety 10.50 ± 4.24 vs 9.50 ± 3.59, p=0.51; depression 11.50 ± 2.56 vs 10 ± 4.44, p=0.26). No adverse effects were reported.

Conclusion: Patients showed improved scores in all applied scales after IV lidocaine treatment, although not statistically significant except for the NPS. In order to confirm these preliminary results we are still recruiting patients to enlarge our sample.