Tolfenamic Acid
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Tolfenamic Acid: From Acute Migraine (International Use) to Headache Disorder
One-Sentence Summary
Tolfenamic acid is a fenamate NSAID with no current marketing authorization in Taiwan; internationally (e.g., UK) it is approved for acute migraine treatment. The TxGNN model predicts it may also be effective for Headache Disorder (broadly), supported by 20 published studies — including multiple double-blind RCTs — though no registered clinical trials were found for this specific indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not formally registered in Taiwan; internationally approved for acute migraine (UK) |
| Predicted New Indication | Headache Disorder |
| TxGNN Prediction Score | 99.74% |
| Evidence Level | L2 (multiple historical double-blind RCTs in literature; no registered clinical trials) |
| Taiwan Market Status | ✗ Not Marketed |
| Number of Registrations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed DrugBank mechanism-of-action data is currently a data gap. Based on available pharmacology literature, tolfenamic acid is an anthranilic acid (fenamate) derivative NSAID that acts as a potent inhibitor of prostaglandin biosynthesis and has also been reported to inhibit leukotriene synthesis. DrugBank pharmacology data additionally lists an interaction with AKR1C3 (aldo-keto reductase family 1 member C3), an enzyme involved in prostaglandin F and steroid metabolism, consistent with the drug’s anti-inflammatory pharmacology.
This mechanism directly supports the drug’s already-established international use in acute migraine: prostaglandins are implicated in migraine-related vasodilation, sensitization of nociceptors, and hyperalgesia, and multiple older RCTs show tolfenamic acid performing comparably to ergotamine, sumatriptan, and paracetamol in acute attacks, and to propranolol/pizotifen in prophylaxis.
The TxGNN prediction of “Headache Disorder” is therefore largely a restatement/extension of an indication the molecule already has strong real-world and trial support for outside Taiwan, rather than a mechanistically novel repurposing hypothesis. The main gap is not scientific plausibility but the absence of Taiwan-specific regulatory data (label, market authorization) needed to act on it locally.
Clinical Trial Evidence
Currently no related clinical trials registered (no entries found in ClinicalTrials.gov or ICTRP for this indication).
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 2375249 | 1990 | RCT (double-blind crossover) | Acta Neurol Scand | Tolfenamic acid 200/400 mg vs. paracetamol 500/1000 mg in acute common migraine |
| 3727918 | 1986 | RCT (double-blind crossover) | Acta Neurol Scand | Tolfenamic acid vs. propranolol vs. placebo for migraine prophylaxis; both active drugs reduced attack frequency/duration |
| 7051739 | 1982 | RCT (double-blind crossover) | Acta Neurol Scand | Tolfenamic acid significantly better than placebo for migraine prophylaxis (attack frequency, duration, vomiting) |
| 7976233 | 1994 | RCT (double-blind crossover) | Acta Neurol Scand | Tolfenamic acid 100 mg TID vs. propranolol 40 mg TID for migraine prophylaxis in 76 patients |
| 9563211 | 1998 | RCT (double-blind, parallel-group) | Headache | Tolfenamic acid rapid release vs. oral sumatriptan for acute migraine; comparable efficacy in 141 patients |
| 12474702 | 2002 | RCT (double-blind, parallel-group) | Medicina (Kaunas) | Tolfenamic acid 300 mg vs. pizotifen 1.5 mg for migraine prevention in 192 patients |
| 89390 | 1979 | RCT (double-blind crossover) | Lancet | Tolfenamic acid vs. ergotamine vs. aspirin vs. placebo in 160 migraine attacks; efficacy comparable to ergotamine with fewer side effects |
| 6984358 | 1982 | Clinical study | Cephalalgia | Tolfenamic acid combined with caffeine, metoclopramide, or pyridoxine in acute migraine (60 attacks) |
| 6394143 | 1984 | Clinical study | Cephalalgia | Tolfenamic acid, metoclopramide, caffeine, and combinations tested in migraine attacks |
| 7816790 | 1994 | Review | Pharmacology & Toxicology | Review of tolfenamic acid in acute and prophylactic migraine treatment, prostaglandin hypothesis |
Taiwan Market Information
Tolfenamic acid currently holds no marketing authorizations in Taiwan (0 registrations, market status: Not marketed/Not Marketed). No license records are available.
Safety Considerations
Please refer to the package insert for safety information. TFDA-specific key warnings and contraindications are not yet available (see Data Gaps below); a pharmacology-level target interaction with AKR1C3 (aldo-keto reductase C3) is recorded in DrugBank, but its clinical drug-drug interaction relevance has not been established.
Conclusion and Next Steps
Decision: Hold
Rationale: Efficacy evidence for headache/migraine is substantial (multiple historical double-blind RCTs vs. placebo, propranolol, pizotifen, sumatriptan, and ergotamine), but the candidate cannot advance to formal safety review (S1) because TFDA label warnings/contraindications are a Blocking data gap, and the drug currently has zero marketing authorizations in Taiwan.
To proceed, the following is needed:
- TFDA label data (warnings, contraindications) — download and parse official package insert (DG001, Blocking)
- DrugBank-confirmed mechanism of action (DG002, High) to formally support the mechanistic rationale
- Classification/tiering of the currently “pending” literature evidence (study type, relevance) to firm up the evidence level
- Assessment of a regulatory pathway for Taiwan market entry, given current non-marketed status
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.