Ketamine for Postherpetic Neuralgia(Shingles)

 

Ketamine for Postherpetic Neuralgia(Shingles) Summary

Research into Ketamine for pain management shows it to be a safe alternative to opioids in emergency settings. A 2025 study has shown that 20-46% of patients achieved clinically meaningful improvements in pain management and found the benefits were sustained 6 months post treatment. A 2025 study found Ketamine to match the effect of opioids for immediate pain relief without the side effects. Overall the studies show that Ketamine is an effective tool for treating pain.

Postherpetic Neuralgia happens when you keep getting pain even after the Shingles rash has disappeared. This happens because of hypersensitivity of the central nervous system because the nerve fibers got damaged during a shingles outbreak. This disease affects about 10-15% of those who get Shingles, a viral infection caused by herpes zoster or chickenpox virus. This complication usually happens in those that are 50+, have severe shingles that are often located on face or torso, suffer from diabetes and took more than 3 days to get anti-virals.

Ketamine is currently being used for pain control for Phantom Limb Pain in order to offer patients a better quality of life.

1) Mechanism of Action

Ketamine is used as an analgesic, especially for severe acute pain and selected chronic pain syndromes.

  • NMDA receptor antagonism causes a reduction in glutamate-mediated pain transmission
  • Decreases central sensitization
  • Inhibits wind-up phenomenon
  • Reduces hyperalgesia and allodynia
  • Enhances descending inhibitory pain pathways

2) Clinical Indications

  • Refractory Postherpetic Neuralgia
  • Severe neuropathic pain
  • Opioid resistant pain

3) Clinical Effects

  • Reduction in pain intensity
  • Decreased allodynia and hyperalgesia
  • Improved quality of life

In chronic pain, ketamine may sometimes provide relief that lasts beyond the infusion period by helping reset abnormal pain processing and can last for days and even weeks after the ketamine session.

4) Potential Advantages

  • Targets central sensitization mechanism
  • Useful in opioid resistant pain
  • May reduce opioid dependency
  • May produce longer lasting relief
  • Rapid results

5) Limitations and Risks

  • Short duration of benefit in some cases
  • Need for monitoring at higher doses
  • Potential for misuse or dependence

6) Adverse Effects

  • Dissociation
  • Hallucinations or perceptual disturbances
  • Dizziness
  • Nausea/vomiting
  • Sedation
  • Increased blood pressure and heart rate

With repeated or long-term use

  • Cystitis (ketamine bladder syndrome)
  • Cognitive effects
  • Potential hepatotoxicity

7) Current Clinical Role

  • Reserved for treating refractory Postherpetic Neuralgia