Ketamine
| 證據等級: L5 | 預測適應症: 1 個 |
目錄
Ketamine: From General Anesthesia to Headache Disorder
One-Sentence Summary
Ketamine is a dissociative anesthetic and NMDA receptor antagonist, historically used for induction and maintenance of general anesthesia and, off-label, for pain management. The TxGNN model predicts it may be effective for Headache Disorder, with 40 clinical trials identified in the search and 20 publications screened, of which a focused subset directly addresses headache/migraine/cluster headache indications.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | General anesthesia (induction/maintenance), dissociative anesthetic — not confirmed in the New Zealand regulatory record (drug is currently unmarketed) |
| Predicted New Indication | Headache Disorder |
| TxGNN Prediction Score | 99.33% |
| Evidence Level | L3 |
| New Zealand Market Status | ✗ Not Marketed |
| Number of Authorizations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the evidence pack (original_moa is a Data Gap). Based on known pharmacology, ketamine is an NMDA receptor antagonist and dissociative anesthetic; its efficacy in general anesthesia is well established, and low ("sub-dissociative") doses are already used off-label as an analgesic in emergency and pain-management settings.
The mechanistic rationale for headache disorder is that NMDA receptor blockade can suppress central sensitization and cortical spreading depression, two processes implicated in the pathophysiology of migraine, cluster headache, and refractory chronic daily headache. This is why a number of tertiary headache/pain centers already use ketamine infusions off-label for status migrainosus and treatment-refractory headache.
This is not ketamine's original approved indication, and the mechanistic link — while biologically plausible and reflected in a growing body of emergency-department and headache-clinic trials — has not yet been confirmed by a large, dedicated Phase 3 program specifically powered for headache disorder.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT03081416 | Phase 3 | Completed | 80 | THINK Trial: randomized, single-blind, placebo-controlled study of intranasal sub-dissociative ketamine vs. standard therapy for primary headache syndromes in the ED |
| NCT05306899 | Phase 3 | Recruiting | 56 | KetHead Study: multicenter, placebo-controlled RCT of high-dose IV ketamine infusion for chronic daily headache via reversal of receptor-mediated sensitization |
| NCT04179266 | Phase 1/2 | Completed | 23 | Proof-of-concept study of intranasal ketamine spray for chronic cluster headache |
| NCT06608277 | Phase 2 | Recruiting | 175 | Multicenter RCT comparing ketamine, stellate ganglion block, and combination therapy vs. sham for TBI-associated headache and PTSD |
| NCT04814381 | Phase 4 | Recruiting | 90 | Single infusion of ketamine combined with magnesium sulfate for refractory chronic cluster headache |
| NCT02657031 | Phase 4 | Completed | 54 | Check Trial: multicenter RCT comparing low-dose ketamine vs. compazine for ED headache control |
| NCT03221569 | Phase 4 | Unknown | 60 | Sub-dissociative ketamine vs. ketorolac for acute tension-type headache/migraine in the ED |
| NCT02697071 | N/A | Completed | 34 | Randomized, double-blind, placebo-controlled trial of sub-dissociative ketamine for acute migraine-type headache in the ED |
| NCT04860713 | Phase 4 | Completed | 5 | Open-label RCT of oral ketamine + aspirin vs. rimegepant for acute ED headache |
| NCT02388321 | Phase 4 | Terminated | 22 | RCT comparing intranasal sub-dissociative ketamine to intranasal fentanyl for moderate-to-severe pediatric ED pain (indirect support; small sample, terminated early) |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 35356451 | 2022 | Cohort | Frontiers in Neurology | Retrospective cohort assessing efficacy, duration, and safety of combined IV lidocaine and ketamine infusions for headache disorders |
| 41321235 | 2026 | Guideline | Headache | 2025 American Headache Society update on parenteral pharmacotherapies (including ketamine) for acute migraine in the emergency department |
| 34919214 | 2022 | Review | Drugs | Review of acute and prophylactic drug therapy for cluster headache |
| 38870050 | 2024 | Review | Expert Review of Neurotherapeutics | Update on trigeminal neuralgia pharmacotherapy noting ketamine as a potential adjuvant alongside newer CGRP-targeted migraine agents |
| 37421541 | 2023 | Review | Current Pain and Headache Reports | Evidence-based review of complex regional pain syndrome, relevant to ketamine's central-sensitization mechanism shared with refractory headache |
New Zealand Market Information
Ketamine currently has no marketing authorization recorded in the New Zealand regulatory data (0 licenses, market status "Not Marketed").
Safety Considerations
Please refer to the package insert for safety information. (Key warnings, contraindications, and drug interaction data are not currently available; the TFDA/Medsafe package insert lookup is flagged as a Blocking data gap that prevents formal S1 safety pre-assessment.)
Conclusion and Next Steps
Decision: Hold
Rationale: The mechanistic rationale (NMDA antagonism → reduced central sensitization/cortical spreading depression) is biologically plausible and supported by one completed Phase 3 RCT (THINK Trial) plus several ongoing Phase 2–4 trials directly targeting migraine, cluster headache, and chronic daily headache — but overall evidence is rated L3, ketamine is not currently marketed in New Zealand, and safety data (warnings, contraindications, DDI) are entirely unavailable, which is a Blocking gap for any S1 safety pre-assessment.
To proceed, the following is needed:
- TFDA/Medsafe package insert (warnings, contraindications) — currently blocking (DG001)
- Confirmed mechanism of action data via DrugBank API (DG002)
- DDI data (current query status: not found)
- Results from ongoing Phase 3 trials (NCT05306899 KetHead Study, expected completion 2026-06; NCT06608277)
- Regulatory assessment of ketamine's controlled-substance/misuse-potential status for the headache indication pathway
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.