Tadalafil
| 證據等級: L5 | 預測適應症: 8 個 |
目錄
- Tadalafil
- Tadalafil: From PDE5-Mediated Vascular Indications to Ambras Type Hypertrichosis Universalis Congenita — Evidence Insufficient
Tadalafil: From PDE5-Mediated Vascular Indications to Ambras Type Hypertrichosis Universalis Congenita — Evidence Insufficient
One-Sentence Summary
Tadalafil is a PDE5 (phosphodiesterase type 5) inhibitor whose established pharmacology acts on vascular smooth muscle and corpus cavernosum tissue, but no approved indication or MOA record is present in this evidence pack. The TxGNN model's top prediction — Ambras type hypertrichosis universalis congenita — has no clinical trials and no supporting literature, and the model's own rationale flags it as a likely embedding artifact rather than a biologically plausible signal. Across all 8 candidate indications screened, none reach a defensible evidence tier; the single most clinically relevant literature hit (a case report) actually describes tadalafil-induced migraine aura, i.e. an adverse effect, not a therapeutic signal.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in evidence pack (no approved indications on file); known PDE5-inhibitor pharmacology targets vascular smooth muscle / corpus cavernosum |
| Predicted New Indication | Ambras type hypertrichosis universalis congenita |
| TxGNN Prediction Score | 99.98% |
| Evidence Level | L5 |
| Norway 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 (flagged as a Blocking/High-severity data gap in this pack). Based on the fragments available, tadalafil is known to act as a PDE5 inhibitor, with pharmacological effects on vascular smooth muscle and corpus cavernosum tissue — the mechanistic basis typically cited for tadalafil's established uses (erectile dysfunction, BPH, pulmonary arterial hypertension), though the specific original indication is not itself recorded in this evidence pack.
The top-ranked prediction, Ambras type hypertrichosis universalis congenita, is a rare congenital hair-growth disorder. There is no known or hypothesized pathway connecting PDE5/cGMP-mediated vasodilation to follicular growth regulation. The model's own rationale explicitly states this score reflects an "embedding similarity artifact" rather than a biologically grounded signal — a conclusion echoed for ranks #2, #4, #5, and #6 (hypertrichosis, Dandy-Walker–associated syndrome, hair shaft abnormality, trichomegaly), all of which score >99.6% with zero clinical trials and zero literature support.
Rank #3 (a periodontal/odontal malformation syndrome) initially looks better supported with 20 literature hits, but on inspection every article addresses general periodontal pathophysiology or treatment — none mention tadalafil or PDE5 inhibitors at all. This is disease-term co-occurrence noise, not drug-relevant evidence. Rank #7 (kyphoscoliotic heart disease) has a theoretically coherent hypothesis (PDE5 inhibitors are used in pulmonary hypertension, which can complicate kyphoscoliosis) but zero supporting trials or literature. Overall, no candidate in this pack clears even a preliminary mechanistic-plausibility bar with real-world evidence.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available for the top-ranked indication (Ambras type hypertrichosis universalis congenita).
Norway Market Information
No marketing authorizations are on file for tadalafil in this evidence pack. Market status is recorded as "Not marketed" with 0 total licenses and no dosage forms/routes listed.
Other Candidate Indications Screened (Context)
Since this evidence pack evaluated 8 candidates for tadalafil, the table below summarizes why each was screened out, for completeness:
| Rank | Disease | TxGNN Score | Evidence | Verdict |
|---|---|---|---|---|
| 2 | Hypertrichosis (disease) | 99.98% | None | No mechanistic link |
| 3 | Odontal/periodontal malformation syndrome | 99.97% | 20 papers, none drug-specific | Co-occurrence noise |
| 4 | Dandy-Walker malformation syndrome | 99.97% | None | No mechanistic link |
| 5 | Isolated genetic hair shaft abnormality | 99.96% | None | No mechanistic link |
| 6 | Familial isolated trichomegaly | 99.65% | None | No mechanistic link |
| 7 | Kyphoscoliotic heart disease | 99.43% | None | Theoretical PAH-overlap hypothesis only, unconfirmed |
| 8 | Migraine with brainstem aura | 99.08% | 1 case report (PMID 17059442) | Adverse-effect signal, not therapeutic evidence — see Safety below |
Safety Considerations
- Key Warnings / Contraindications: Not available in this evidence pack (TFDA/label data flagged as a Blocking data gap — DG001).
- Drug Interactions: No DDI data returned (query status: not found).
- Literature-derived safety signal: A case report (PMID 17059442, Cephalalgia, 2006) describes tadalafil-associated typical migraine aura without headache. This suggests PDE5-inhibitor–mediated cerebral vasodilation can provoke migraine-aura-like events — the opposite of a therapeutic effect for migraine, and worth noting as a precaution rather than a repurposing lead.
Conclusion and Next Steps
Decision: Hold
Rationale:
All 8 candidate indications sit at Evidence Level L5 (or L4 for a single adverse-event case report), with decision_stage: S0 and no clinical trial or drug-specific literature support. The highest-scoring predictions are explicitly flagged by the model's own rationale as embedding artifacts. No candidate in this pack meets the threshold to advance past initial screening.
To proceed, the following is needed:
- Resolve DG001 (Blocking): obtain TFDA/label warnings and contraindications — required before any S1 safety pre-assessment can begin.
- Resolve DG002 (High): obtain confirmed MOA and approved indications from DrugBank — required to establish a genuine mechanistic rationale for any candidate.
- If pursuing rank #7 (kyphoscoliotic heart disease / pulmonary hypertension overlap) further, commission a targeted literature search for tadalafil in kyphoscoliosis-associated pulmonary hypertension specifically, since the current pack found no drug-specific studies.
- No further action recommended on ranks #1–6, #8 without new experimental or clinical data — these are not viable repurposing leads based on current evidence.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.