Short- and Midterm Analgesic Outcomes of Ketamine Versus Lidocaine Infusion in Chronic Peripheral Neuropathic Pain: A Retrospective Study

Ketamine may provide greater neuropathic pain relief than lidocaine for some patients.

In this study researchers reviewed 102 patients with chronic peripheral neuropathic pain treated at a pain clinic: 44 received ketamine and 58 received lidocaine. Patients received five consecutive daily 1-hour IV infusions: ketamine 1 mg/kg/h or lidocaine 3 mg/kg/h. Pain was assessed at baseline and at 2 weeks, 2 months and 6 months using the Numeric Rating Scale (NRS) and DN4 neuropathic-pain questionnaire.

Both treatments significantly reduced pain and neuropathic symptoms at 2 weeks, 2 months and 6 months.

Ketamine produced a greater early analgesic response at 2 weeks: ≥50% NRS pain reduction in 86.4% vs 50.0% with lidocaine.

By 2 and 6 months, there was no significant difference between treatments.

At 6 months, meaningful NRS pain relief was 59.1% with ketamine vs 58.6% with lidocaine.

Adverse effects were more common with ketamine; lidocaine had the more favourable tolerability profile.

Overall, the findings suggest a stronger short-term effect with ketamine but comparable mid-term outcomes.

Abstract

Background

Intravenous ketamine and lidocaine infusions are increasingly used for chronic peripheral neuropathic pain, particularly in refractory cases. However, comparative data on their short- and midterm analgesic outcomes in routine clinical practice are limited.

Methods

This retrospective study included patients with chronic peripheral neuropathic pain who received intravenous ketamine or lidocaine infusion between January and May 2021. Ketamine was administered at 1 mg/kg/h and lidocaine at 3 mg/kg/h for five consecutive days. Pain intensity and neuropathic pain features were assessed using the Numeric Rating Scale (NRS) and the Douleur Neuropathique 4 (DN4) questionnaire at baseline and at 2 weeks, 2 months, and 6 months after treatment. Clinically meaningful pain relief was defined as a ≥ 50% reduction in pain scores.

Results

A total of 102 patients were analyzed (ketamine group, n = 44; lidocaine group, n = 58). Both groups showed significant reductions in NRS and DN4 scores at all follow-up points compared with baseline (p < 0.01). Clinically meaningful pain relief was more frequent in the ketamine group at 2 weeks (p < 0.01), whereas no significant differences were observed at 2 and 6 months (p > 0.05). Adverse effects occurred more often with ketamine, while lidocaine was associated with fewer side effects (p < 0.05).

Conclusion

Ketamine provided a greater early analgesic response at 2 weeks, whereas both treatments demonstrated comparable midterm efficacy at 2 and 6 months.

Sucu, Mevlüt Gökhan, Yavuz Mollavelioğlu, Tuğçe, Akyüz Yildirim, Ayşegül, Çelebi, Nalan, Short- and Midterm Analgesic Outcomes of Ketamine Versus Lidocaine Infusion in Chronic Peripheral Neuropathic Pain: A Retrospective Study, Pain Research and Management, 2026, 7897619, 9 pages, 2026. Read Paper

For more psychedelic news and research, visit the psychedelic health professional network homepage.