Lidocaine Raised Endorphins in Diabetic Neuropathy Patients But Pain Relief Was Unrelated | Research

The takeaway

Lidocaine infusion increased beta-endorphin equally in diabetic neuropathy patients and controls, but pain relief in patients did not correlate with endorphin changes.

Pain relief independent of endorphins
Lidocaine neuropathy relief through nerve-blocking, not opioid mechanisms

What the researchers found

Lidocaine increased plasma beta-endorphin equally in patients and controls, but pain relief in diabetic neuropathy was not correlated with beta-endorphin changes.

Why it matters

This suggests lidocaine relieves diabetic nerve pain through a mechanism other than the opioid system. The beta-endorphin rise appears to be a general response to lidocaine, not specific to pain relief.

How the study worked

Blood opioid peptides were measured by radioimmunoassay before and after lidocaine infusion in 8 diabetic neuropathy patients and 10 controls. Pain was scored before and after treatment.

What this study cannot tell us

Very small study with only 8 patients. Only blood peptide levels were measured, which may not reflect what happens in the nervous system. No placebo control.

How to read the evidence

Preliminary cross-sectional study — small but with direct plasma peptide measurements.

When this study was published

Published in 1989 — clarified lidocaine mechanism in neuropathic pain.

The bigger picture

Lidocaine pain relief in neuropathy appears to work through direct nerve effects, not the opioid system. This is important for understanding and optimizing neuropathic pain treatments.

Questions still open

Could combining lidocaine with opioid peptide therapy improve outcomes?
Why does lidocaine increase endorphins if the mechanism is non-opioid?

Common questions

How does lidocaine relieve nerve pain?

Lidocaine blocks sodium channels in damaged nerves, silencing the abnormal electrical signals that cause neuropathic pain. It works directly on the nerves, not through the opioid system.

Why did endorphins increase if they did not cause the pain relief?

Lidocaine may trigger endorphin release through secondary mechanisms unrelated to its pain-relieving action. The endorphin increase appears to be a separate, coincidental effect.

Read the original research

Lidocaine treatment of painful diabetic neuropathy and endogenous opioid peptides in plasma.

The Clinical journal of pain, 5(3), 239-44

View on PubMed ↗

Citation

Kastrup, J; Bach, F W; Petersen, P; Dejgård, A; Ekman, R; Jensen, S; Angelo, H. (1989). Lidocaine treatment of painful diabetic neuropathy and endogenous opioid peptides in plasma.. The Clinical journal of pain, 5(3), 239-44.