Efficacy of Lidocaine Infusion for Treatment of Chronic Neuropathic Pain: A Case Control Study

Abstract

Background: Neuropathic pain is a type of chronic pain that is related to nerve damage and is defined by the International Association of Study of Pain (IASP) as “pain caused by a disease or lesion of the somatosensory nervous system”. It remains a challenging clinical problem as pain often can be quite severe and debilitating. The rationale of this study is to find out the efficacy of intravenous lidocaine infusion for neuropathic pain management in our population as there has been no study conducted in Pakistan for this purpose. As our country has a rather low-income population and cheaper options for treatment need to be explored. Objective: To determine the efficacy of lidocaine infusions of 3 mg/kg in managing the chronic neuropathic pain given at 0,1, 2 and 3 weeks in comparison to the placebo infusion. Study Design: Case control study. Settings: The study was conducted in the Sheikh Zayad Hospital Lahore Pakistan. Duration: July 2022 to December 2022. Methods: 100 outdoor patients fulfilling the inclusion and exclusion criteria were enrolled after taking informed written consent and were randomly allocated to Lidocaine group (A) 3 mg/kg, diluted in 50 ml normal saline and placebo group (B) 50 ml intravenously over 30 minutes. The Lidocaine group was injected with lidocaine, intravenously over 30 minutes once a week for 4 weeks. Patients with established diagnosis of neuropathic pain, adults of both genders, age above 18 years were enrolled in this study. Their pain severity was recorded using Numerical rating scale (NRS). The data of both groups was recorded in predesigned proforma and efficacy was also noted as labelled as Yes/No for two points; 1: Decrease in pain score by at least 2 out of 10   and 2: Decrease in oral analgesics intake. Results: There were 50 patients in group A and B with the mean age of 53.82 years and 54.4 years respectively. Patients in group A who received an intravenous infusion of lidocaine reported less severe pain and fewer instances of breakthrough pain. No statistically significant difference (P>0.05) was discovered between NRS ratings before and after infusions in the control group despite the fact that several patients reported lower pain intensity after the infusion. The quantity of opioid used was determined for the Lidocaine and Placebo groups. Opioid in the placebo group was 0.472–0.572 g per patient, but in the Lido group it was only 0.1–0.2 g per patient which is significantly different from placebo group (p=0.0021). Conclusion: Lidocaine intravenous infusion (3 mg/kg daily for 4 weeks) improved short-term results of therapy, decreased the need for analgesic medication, and shortened pain score without causing major adverse effects.