Tolfenamic Acid
| Evidence Level: L1 | Predicted Indications: 10 |
Table of Contents
Tolfenamic Acid: From General Pain and Inflammation to Headache Disorder (Migraine)
One-Sentence Summary
No UK marketing authorisation or documented original indication is on record for tolfenamic acid in this evidence pack, though literature within the pack identifies it as a fenamate-class NSAID used for pain and inflammation. The TxGNN model predicts it may be effective for Headache Disorder (Migraine), with 20 publications — including several historical double-blind randomised controlled trials — currently supporting this direction, though no clinical trials are registered in modern trial databases.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not available — no UK marketing authorisation on record. Literature within this pack describes tolfenamic acid as an anthranilic acid (fenamate) NSAID used for pain and inflammation. |
| Predicted New Indication | Headache Disorder (Migraine) |
| TxGNN Prediction Score | 99.74% |
| Evidence Level | L1 |
| UK Market Status | Not Marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Detailed mechanism of action data for tolfenamic acid is not currently available from DrugBank in this evidence pack. Based on information contained in the supporting literature, tolfenamic acid is a fenamate-class NSAID (anthranilic acid derivative) that inhibits both cyclooxygenase (prostaglandin synthesis) and lipoxygenase (leukotriene synthesis) pathways. This dual inhibition distinguishes it from purely COX-selective NSAIDs and has been proposed as the basis for its efficacy in migraine.
Prostaglandins and leukotrienes are implicated in the pathophysiology of migraine through nociceptor sensitisation, hyperalgesia, vasodilation, and platelet-mediated serotonin release — mechanisms directly discussed in the earliest reviews within the literature evidence (e.g. Hansen 1994; Vapaatalo 1994). This provides a mechanistically coherent rationale for TxGNN’s prediction linking an NSAID with anti-prostaglandin/anti-leukotriene activity to headache disorder, independent of the drug’s original (undocumented) indication.
Notably, tolfenamic acid already has a long-standing, well-documented history of clinical use specifically in migraine (predominantly in Scandinavian countries from the late 1970s through the 1990s), which strengthens confidence in the TxGNN prediction beyond a purely computational association.
Clinical Trial Evidence
Currently no related clinical trials registered (no entries found in ClinicalTrials.gov or ICTRP-linked registries for this indication).
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 12474702 | 2002 | RCT (double-blind, parallel-group) | Medicina (Kaunas) | Tolfenamic acid 300 mg vs pizotifen 1.5 mg in 192 patients with 4–8 monthly migraine attacks; prospective randomised comparison for prophylaxis. |
| 9563211 | 1998 | RCT (double-blind, randomised, parallel-group) | Headache | Tolfenamic acid vs oral sumatriptan in 141 patients (289 attacks); 77% of tolfenamic-acid-treated attacks reduced from severe/moderate to mild/no headache. |
| 7976233 | 1994 | RCT (double-blind, cross-over) | Acta Neurologica Scandinavica | Tolfenamic acid 300 mg/day vs propranolol 120 mg/day in 76 migraine patients over 12 weeks; both significantly reduced attack frequency/duration. |
| 89390 | 1979 | RCT (double-blind, cross-over) | Lancet | Tolfenamic acid vs ergotamine, aspirin, and placebo across 160 attacks in 20 women; equally effective to ergotamine but with fewer side effects (less nausea). |
| 3727918 | 1986 | RCT (double-blind, cross-over) | Acta Neurologica Scandinavica | Tolfenamic acid vs propranolol vs placebo in 31 patients for migraine prophylaxis; both active drugs significantly reduced attack number and duration vs placebo. |
| 7051739 | 1982 | RCT (double-blind, cross-over) | Acta Neurologica Scandinavica | Tolfenamic acid vs placebo in 31 patients for migraine prophylaxis; tolfenamic acid preferred by patients, with reduced attack number, duration, severity, and vomiting. |
| 2375249 | 1990 | RCT (double-blind, cross-over) | Acta Neurologica Scandinavica | Tolfenamic acid (200/400 mg) vs paracetamol (500/1000 mg) in acute migraine, across at least 4 attacks per treatment arm per patient. |
| 10234467 | 1999 | Retrospective study | Cephalalgia | Tolfenamic acid added to sumatriptan reduced migraine recurrence in 50 patients who had frequent recurrence with sumatriptan alone. |
| 7816790 | 1994 | Review | Pharmacology & Toxicology | Overview of the proposed role of prostaglandins in migraine and tolfenamic acid’s use in acute and prophylactic treatment. |
| 8749241 | 1995 | Review | Cephalalgia | Review of analgesics and NSAIDs, including tolfenamic acid, in the treatment of acute migraine attacks. |
UK Market Information
Tolfenamic acid does not currently hold a UK marketing authorisation (0 licences on record in this evidence pack) and is not listed in the current BNF. It is not classified as “Not Marketed” for regulatory/commercial reasons documented here — no licensing history, product name, or dosage form data are available.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Note: This evidence pack flags the absence of UK/TFDA-equivalent product warnings, contraindications, and drug–drug interaction data as a Blocking data gap (DG001), meaning a formal safety pre-assessment (S1) cannot currently be completed for this candidate.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: Tolfenamic acid has a substantial historical evidence base for migraine, including at least six double-blind randomised controlled trials (some with over 100 participants) comparing it against active comparators such as sumatriptan, propranolol, ergotamine, and paracetamol, supporting an evidence level of L1. However, this evidence predates modern clinical trial registries, and critical safety and regulatory data (UK/TFDA labelling, mechanism of action, marketing status) remain unavailable, warranting guardrails before any further development decision.
To proceed, the following is needed:
- UK/MHRA-equivalent product safety data: key warnings, contraindications, and drug–drug interactions (currently a Blocking gap)
- Confirmed mechanism of action data from DrugBank or equivalent pharmacological source
- Clarification of current global marketing/licensing status, since the drug holds no UK authorisation
- A contemporary systematic review or updated RCT to validate historical 1979–2002 findings against current migraine treatment standards
- Registration or identification of trials in modern registries (ClinicalTrials.gov, ISRCTN, EU CTR) to support formal trial-based evidence grading
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.