Tadalafil

Evidence Level: L5

Predicted Indications: 8

Tadalafil

Pharmacist Assessment Report

Tadalafil: Ambras type hypertrichosis universalis congenita

One-Sentence Summary

Tadalafil is a PDE5 inhibitor originally used for erectile dysfunction, benign prostatic hyperplasia and pulmonary hypertension, among other conditions. The TxGNN model predicts it may be effective for Ambras-type hypertrichosis universalis congenita, but there are currently 0 clinical trials and 0 publications supporting this prediction, so it rests on computational prediction alone.

Quick Overview

Item	Content
Original Indication	Not recorded in the local data
Predicted New Indication	Ambras type hypertrichosis universalis congenita
TxGNN Prediction Score	0.9998
Evidence Level	L5
Canada Market Status	Marketed (marketed DINs on record: at least 20)
Number of DINs	at least 20
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available. Based on known information, tadalafil is a PDE5 inhibitor that raises cGMP levels. Its efficacy in erectile dysfunction and pulmonary hypertension is established, but no mechanism links it to this rare congenital hypertrichosis.

The very high TxGNN score is a computational prediction only. It is probably driven by network proximity to other hair-phenotype diseases rather than by biological evidence. Vasodilation and cGMP signalling could in theory affect hair follicle biology, but this is speculative. Related vasodilators such as minoxidil are associated with hypertrichosis, which suggests an adverse-effect signal rather than a therapeutic one.

Other Predicted Indications (for Context)

The model also ranked the following conditions. None has any clinical trial support, and all remain at evidence level L5 except where noted.

Rank	Predicted Indication	TxGNN Score	Evidence Level	Comment
2	Hypertrichosis	0.9998	L5	Speculative link; may reflect an adverse-effect signal
3	Malformation syndrome with odontal and/or periodontal component	0.9997	L5	No identifiable mechanistic link
4	Syndrome with Dandy-Walker malformation as major feature	0.9997	L5	Structural brain anomaly; no expected benefit
5	Isolated genetic hair shaft abnormality	0.9996	L5	No plausible pathway
6	Familial isolated trichomegaly	0.9965	L5	No established mechanism
7	Kyphoscoliotic heart disease	0.9943	L5	Partial rationale through secondary pulmonary hypertension, but no data
8	Migraine with brainstem aura	0.9908	L5	Only a case report, and it suggests tadalafil may trigger aura

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

For the top predicted indication, currently no related literature is available.

For context, the only publication found across the predicted indications relates to rank 8 (migraine with brainstem aura):

PMID	Year	Type	Journal	Key Findings
17059442	2006	Case report	Cephalalgia	Tadalafil associated with typical migraine aura without headache, suggesting a possible adverse-event signal rather than a treatment benefit

Canada Market Information

There are 20 valid single-ingredient authorisations, with none cancelled. Dosage form and approved-indication text are not available in the records. The first five are listed below.

DIN	Product Name	Dosage Form	Approved Indication
02410656	MYLAN-TADALAFIL	–	–
02457016	TADALAFIL	–	–
02512289	PRZ-TADALAFIL	–	–
02481405	AG-TADALAFIL	–	–
02455366	TADALAFIL	–	–

Safety Considerations

Contraindications suggested by the knowledge graph (these come from knowledge-graph relationships, not from package insert text):
- Cardiovascular: acute coronary syndrome, myocardial infarction, coronary thrombosis, stroke and cerebrovascular disorders, cerebral infarction, hypotensive disorder, aortic stenosis and aortic valve disease, hypertrophic cardiomyopathy
- Haematological: sickle cell anaemia, hemoglobinopathy, blood coagulation disease, plasma cell myeloma, leukaemia
- Penile conditions: priapism, Peyronie disease, penile fibromatosis, balanitis xerotica obliterans
- Other: liver failure, epilepsy, hearing loss disorder, functional visual loss
Drug Interactions: The interaction query returned 100 records. Those listed include:
- Moderate: aprepitant, dexamethasone, clarithromycin, cimetidine, miconazole, clotrimazole, lorcaserin, sapropterin, troglitazone, and the SGLT2 inhibitors canagliflozin, dapagliflozin, empagliflozin and ertugliflozin
- Minor: papaverine
- Unknown severity: pantoprazole, glimepiride, doxycycline, morphine, metformin, omeprazole
Please refer to the package insert for official warnings and contraindications.

Conclusion and Next Steps

Decision: Hold

Rationale: The prediction is supported only by a model score, with no clinical trials, no literature, and no plausible mechanism. Related evidence for hypertrichosis points toward an adverse-effect signal rather than a therapeutic one. None of the other top predictions has trial support either, and the only published evidence (migraine with brainstem aura) suggests possible harm.

To proceed, the following is needed:

Detailed mechanism of action data, and a mechanistic hypothesis linking PDE5 inhibition to hair follicle biology
Preclinical or case-level evidence for the predicted indication
Health Canada package insert warnings and contraindications, which are required before any safety screening
Assessment of whether the hypertrichosis signal reflects a therapeutic effect or an adverse effect
If the project looks for a better-supported lead, consider kyphoscoliotic heart disease, which has a partial biological rationale through pulmonary hypertension, though it too has no supporting data yet
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.