|Year : 2023 | Volume
| Issue : 1 | Page : 13-17
Evaluation of Efficacy of Two Different Doses of Intravenous Lidocaine in Patients with Chronic Pain
Anju Ghai, Bharti Verma, Kanika Rohilla
Department of Anaesthesiology and Critical Care, PGIMS, Rohtak, Haryana, India
|Date of Submission||12-Jan-2023|
|Date of Acceptance||26-Jan-2023|
|Date of Web Publication||28-Apr-2023|
Department of Anaesthesiology and Critical Care, PGIMS, Rohtak 124001, Haryana
Source of Support: None, Conflict of Interest: None
Background: An intravenous infusion of lidocaine has been used on numerous occasions to produce analgesia in neuropathic pain. It has been shown to be beneficial for the treatment of variety of neuropathic pain states in a wide range of dosage, from 2 to 7.5 mg/kg. The aim of our study was to evaluate the efficacy of two different doses of intravenous lidocaine (3 and 4 mg/kg) in patients with chronic pain. Methods: Patients above the age of 18 years suffering from chronic pain due to postherpetic neuralgia, post-surgical scar pain, chronic low back pain having numeric analogue scale (NAS) pain score of ≥3 without satisfactory pain relief from conservative treatment were randomised to receive either 3 mg/kg or 4 mg/kg intravenous lidocaine in 250 mL normal saline infusions weekly over a period of 1 hour for 3 weeks. NAS was measured before starting each infusion, immediately after completion of infusion, 2 and 24 hours, 7th day, 14th day, 21st day, and 28th day. Results: NAS score at first hour and 24th hour was significantly reduced (P = 0.001), after each infusion [7th, 14th day] in both the groups. There was no statistical difference in pain score among both groups except for day 7 (P value 0.04). Reduction in NAS score was also present on 21st and 28th day in both groups, but it did not reach a significant value. On 28th day, NAS score values showed increasing trend. Duration of pain relief was around 1 week after each infusion in both groups. Conclusion: Intravenous lidocaine at a dose of 3 mg/kg or 4 mg/kg was effective in reducing pain in patients with chronic pain. The analgesic effect was not different among both groups. Trend of greater response was observed with 4 mg/kg dose.
Keywords: Chronic neuropathic pain, intravenous lidocaine, numeric analog scale [nas]
|How to cite this article:|
Ghai A, Verma B, Rohilla K. Evaluation of Efficacy of Two Different Doses of Intravenous Lidocaine in Patients with Chronic Pain. MAMC J Med Sci 2023;9:13-7
|How to cite this URL:|
Ghai A, Verma B, Rohilla K. Evaluation of Efficacy of Two Different Doses of Intravenous Lidocaine in Patients with Chronic Pain. MAMC J Med Sci [serial online] 2023 [cited 2023 Jun 6];9:13-7. Available from: https://www.mamcjms.in/text.asp?2023/9/1/13/375337
| Introduction|| |
Lidocaine is a common amino amide-type local anaesthetic and antiarrhythmic drug. It has also been used to relieve several kinds of neuropathic pain, including post herpetic neuralgia and intractable trigeminal neuralgia.,, This therapeutic potential lies in the fact that systemic lidocaine and its oral congeners can block sodium channels in a dose-dependent fashion in both the peripheral and the central nervous system.,, Systemic reviews have suggested that lidocaine infusion is an effective treatment for neuropathic pain. A wide range of lidocaine dosages have been used in previous studies from 2 to 7.5 mg/kg, causing ambiguous results and dose-related adverse effects. Intravenous lidocaine infusion was shown to be beneficial in the treatment of chronic pain, which are typically resistant to more traditional therapies. The aim of this study was to compare analgesic effects of low doses of lidocaine (3, 4 mg/kg).
| Methods|| |
The study was conducted in the Department of Anaesthesiology and Critical Care by Pt. B. D. Sharma UHS, Rohtak from February 2020 to April 2021 in a prospective, randomized, double-blind manner after obtaining approval from institutional Ethical Committee.
Patients above the age of 18 years suffering from chronic pain due to post-herpetic neuralgia, post-surgical scar pain, fibromyalgia, chronic regional pain syndrome I and II, chronic low back pain having numeric analogue scale (NAS) pain score of ≥3 without satisfactory pain relief from conservative treatment (anticonvulsants, antidepressants, opioids, and interventional procedures such as sympathetic blockade) presenting to the pain clinic OPD were included. Patients with any history of severe cardiac illness, heart rate of less than 55 beats/min or greater than 100 beats/ min on ECG, allergies to lidocaine or other local anaesthetics, pregnant and lactating females, any serious concurrent systemic diseases such as myasthenia gravis, decreased lung function, liver problems, severe renal impairment, shock, or hypokalaemia or hyperkalaemia, psychiatric disorders, including schizophrenia, somatization, or acute anxiety, which would restrict the use of lidocaine or compromise their safety were excluded. Aetiology of chronic pain, duration and distribution of pain, ongoing drug therapy (anticonvulsants, antidepressants and opioids) along with dosages were noted. Pain score was evaluated using NAS (scale from 0 to 10, with 0 being no pain and 10 being worst imaginable pain).
Patients were randomised using random number table into two groups. Group 1: 3 mg/kg and group 2: 4 mg/kg. Group 1 received infusion of 3 mg/kg of preservative free lidocaine hydrochloride mixed with 250 mL of normal saline. Group 2 received infusion of 4 mg/kg of lidocaine hydrochloride mixed with 250 mL of normal saline. Infusions were administered over 1 hour. Patients were carefully monitored during the infusion with continuous three-lead electrocardiograph (ECG), non-invasive blood pressure and pulse rate and oxygen saturation. Any adverse effects, such as arrhythmia, blurred vision, headache, malaise, metallic taste, nausea and vomiting, perioral numbness and tingling, sedation, tinnitus, and tremors, were noted and managed accordingly. Patient was monitored for 2 hours after completion of infusion. An evaluation of patient’s pain score using a NAS was done before starting each infusion, immediately after completion of each infusion, 2 and 24 hours after completion of infusion.
Patients were instructed to report any significant change in pain score at any time and were instructed to keep a daily score of the baseline pain (worst pain lasting for at least 30 minutes) for a period of next 7 days. During the study period, the patient continued his/her ongoing oral medication. Readings of heart rate, BP, oxygen saturation were noted at the start of infusion, at 30 minutes and at 1 hour. Patients received 2nd and 3rd infusion of same dose on 7th and 14th day and were evaluated for outcome parameters on 7th, 14th, 21st, and 28th day.
The data were coded and entered into Microsoft Excel spreadsheet. Analysis was done using SPSS version 20 (IBM SPSS Statistics Inc., Chicago, IL, USA) Windows software program. Descriptive statistics included computation of percentages, means and standard deviations. The Mann–Whitney U test (for quantitative data to compare two independent two groups) was used for quantitative data comparison of all clinical indicators. Chi-square test was used for qualitative data whenever two or more than two groups were used to compare. Level of significance was set at P ≤ 0.05.
| Results|| |
Thirty patients were enrolled in the study. Demographic data and patient’s characteristics are shown in [Table 1]. Mean pain intensity scores after first, second, third lidocaine infusions are shown in [Table 2] and [Table 3] and [Figure 1], respectively. [Figure 2] shows inter-group comparison. Side effects are depicted in [Figure 3].
| Discussion|| |
This prospective, randomised, double-blind study showed that both doses of IV lidocaine had significant analgesic effects in patients with chronic neuropathic pain. In our study, pain relief after treatment did not differ significantly among both groups. Our study is comparable to the study by Park et al. who compared placebo, 1, 5 mg/kg IV lidocaine in 500 mL of normal saline over a period of 1 hour three times at least 2 weeks apart, in 18 patients of failed back surgery syndrome. They observed significant reduction in VAS in all the groups but no difference among groups. Their study differed that they observed additional characteristics of pain in their study and found no difference in amount of pain among three groups except sharp, dull, cold and deep pain.
Viola et al. in a study on 15 patients of painful diabetic neuropathy compared two doses of IV lidocaine 5 and 7.5 mg/kg versus saline over 4 hours at 4 weekly intervals for five times. Significant benefit was present 14 days after the infusion and persisted for up to 28 days. There was a trend to a greater response to lignocaine at a dose of 7.5 mg/kg compared with 5 mg/kg, but it did not reach significance. In our study, also, there was a trend to a greater response to lignocaine at a dose of 4 mg/kg compared with 3 mg/kg, but this did not reach significance. But analgesic effect lasts for 7 days only in our study which was 28 days in the earlier study.
Hutson et al. in a retrospective analysis on 58 patients described the efficacy and toxicity of intravenous (i.e.) lidocaine infusions for the treatment of neuropathic pain. An intravenous infusion of 500 mg lidocaine over 30 minutes was administered as the initial trial dose. Patients were observed for 30 minutes post infusion to assess adverse effects. Patients were educated on common lidocaine side effects, signs of a serious reaction and instructed to rate their pain (pain severity scoring range of 1 to 10, with 10 being worst imaginable pain). Based upon patient response and tolerance of the trial infusion, the physician chose to continue, discontinue, or adjust the dose and assign a frequency to the infusions. Fifteen of the 58 patients did not tolerate the full trial infusion dose or required a rate reduction due to adverse events. The average rate for all infusions was 9.1 mg min−1. Only 23 (51%) of the 45 subjects continuing infusions remained at the trial infusion rate of 16.7 mg min−1. Out of those 23 subjects, only eight continued all subsequent infusions at this rate. Excluding each patient’s initial trial infusion, 89% of infusion rates were between 4 and 14 mg min−1 (mean 9.1 mg min−1). Dose reductions were required in 26 (57.8%), and rate reductions were required in 38 (82%) of the 45 patients that continued infusions after the first dose. The average interval at which patients received infusions was every 19.4 days. Efficacy was seen in 45 patients (65%), and all but eight patients (12%) required infusion rate reductions from the initial test rate of 16.7 mg min−1 due to adverse effects. They concluded that adverse effects occurred more commonly at higher lidocaine infusion rate. Side-effects observed in our study did not prompt us to decrease the doses.
There were several limitations to the present study. First, small sample size was used. Serum lidocaine levels were not measured. Patients with different neuropathic pain conditions with a small sample size were used.
| Conclusion|| |
This study suggests that intravenous lidocaine at a dose of 3 mg/kg or 4 mg/kg was effective in reducing pain in patients with chronic neuropathic pain. Our infusion protocol was safe and well tolerated during the trial period. The analgesic effects of lidocaine observed were not different among 3 and 4 mg/kg of lidocaine. Trend of greater response was observed with 4 mg/kg dose of lignocaine. Side effects were mild and transient and did not require any intervention. However, long-term pain relief was not observed after discontinuation of infusions. Further studies using larger sample sizes, long followup, and more consecutive infusions will be required.
Financial support and sponsorship
Conflicts of interest
The authors report no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]