Tadalafil
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Tadalafil: From PDE5 Inhibitor to Ambras Type Hypertrichosis Universalis Congenita
One-Sentence Summary
Tadalafil is a PDE5 inhibitor that is marketed in South Africa under 3 SAHPRA registrations. The TxGNN model predicts it may be effective for Ambras type hypertrichosis universalis congenita, a rare genetic condition. There are currently 0 clinical trials and 0 publications supporting this prediction, so it rests on the model score alone.
Quick Overview
| Item | Content |
|---|---|
| Predicted New Indication | Ambras type hypertrichosis universalis congenita |
| TxGNN Prediction Score | 99.98% |
| Evidence Level | L5 (model prediction only) |
| South Africa Market Status | Marketed |
| Number of SAHPRA Registrations | 3 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the evidence pack. Tadalafil is a PDE5 inhibitor, and PDE5 inhibition raises cGMP, which drives vasodilation. Its use in pulmonary arterial hypertension is established.
The mechanistic link to the predicted indication is weak. Ambras syndrome is a genetic disorder caused by a chromosomal position effect on regulation of the TRPS1 gene. A cGMP-mediated vasodilatory effect is not expected to correct it. The very high score (99.98%) is most likely a knowledge-graph artefact, driven by graph proximity to other hair and rare-disease nodes, and it has no clinical support.
The other top-ranked predictions show the same pattern. Most are hair phenotypes or developmental malformation syndromes, and they include both hypertrichosis and hypotrichosis, which are opposite phenotypes. This suggests the scores reflect a generic hair-phenotype association rather than a real therapeutic signal.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available for the top-ranked prediction.
For a lower-ranked prediction (migraine disorder, rank 9), one report points toward harm rather than benefit:
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 17059442 | 2006 | Case report | Cephalalgia | Tadalafil associated with typical migraine aura without headache |
South Africa Market Information
| Registration Number | Product Name | Dosage Form |
|---|---|---|
| Reg. No. 52/7.1.5/0841.837 | Trado 10 | Fct |
| Reg. No. 51/7.1.5/0391 | Tidalis 20 | Fct |
| Reg. No. 41/7.1.5/0645 | Cialis Oad, 2.5Mg | Tablet |
Safety Considerations
Please refer to the SAHPRA-approved Professional Information (PI) for safety information. Report adverse drug reactions to SAHPRA.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction has no trials or literature behind it. The proposed mechanism does not fit a genetic, structural hair disorder. The only related signal in the retrieved literature (tadalafil-associated migraine aura) points toward possible harm. There is no basis to advance this candidate.
To proceed, the following is needed:
- The SAHPRA package insert warnings and contraindications (a blocking gap for safety screening)
- Mechanism of action data from DrugBank, to allow a proper mechanistic-link analysis
- Any preclinical or clinical evidence linking PDE5 inhibition to the TRPS1 or hair follicle pathway in Ambras syndrome
- A review of the other ranked predictions. Kyphoscoliotic heart disease (indirect plausibility via pulmonary hypertension) is the only one with a coherent, if unverified, rationale.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.