Adapalene

Evidence Level: L5

Predicted Indications: 1

Adapalene

Pharmacist Assessment Report

Adapalene: topical retinoid (RAR-beta/gamma agonist) → zinc, elevated plasma

One-Sentence Summary

Adapalene is a topical retinoid marketed in Australia as a combination gel. The TxGNN model predicts it may be relevant to zinc, elevated plasma, but there are no clinical trials and no publications supporting this direction, so it rests on model prediction alone.

Quick Overview

Item	Content
Original Indication	Not recorded in the local data
Predicted New Indication	zinc, elevated plasma
TxGNN Prediction Score	0.9951
Evidence Level	L5
Australia Market Status	Listed on the PBS Schedule (1 of 1 items) – TGA (ARTG) registration status is not included in this data
Number of PBS Items	1 (valid: 1)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the data compiled for this report. As general pharmacological background, adapalene is a topical retinoid that selectively binds retinoic acid receptors (RAR-beta and RAR-gamma) and modulates keratinocyte differentiation and inflammation.

No clinically supported mechanistic link between these actions and systemic zinc homeostasis (such as zinc transporters, metallothionein or albumin binding) was identified. The high score (0.9951) is a model output only. It may reflect network proximity through shared gene or pathway nodes rather than a true pharmacological effect.

Elevated plasma zinc is also a laboratory finding more than a disease with a defined treatment target, so the clinical meaning of this prediction is unclear. Adapalene is applied topically, and a route-compatibility assessment for a systemic condition has not been completed.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

Currently no related literature available.

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
13363H	Epiduo	Gel 1 mg-25 mg per g, 30 g	Not recorded in the local data

This is a combination product licence (listed as a single-ingredient entry in the data), so it should not be taken to describe how adapalene alone is approved. The dosage form is topical.

Safety Considerations

No label-based warnings or contraindications are available in the data compiled for this report. Please refer to the TGA-approved Product Information (PI) for safety information.

Drug Interactions: 58 potential interactions were identified, all with an unclassified severity level. Examples include:

Doxycycline, minocycline and tetracycline
Pantoprazole, omeprazole and rabeprazole
Prednisone, triamcinolone and budesonide
Metronidazole, fluconazole and ibuprofen
Clopidogrel and bupropion

Interaction severity has not been graded, so these should be reviewed against the PI and a clinical interaction resource.

Conclusion and Next Steps

Decision: Hold

Rationale: The prediction has no supporting clinical trials or publications (Evidence Level L5). No plausible mechanistic link to zinc handling was identified, and the target condition is a laboratory finding rather than a treatable disease. The topical-only product also raises a route question for a systemic indication.

To proceed, the following is needed:

Mechanism of action data and a defined mechanistic hypothesis linking adapalene to zinc homeostasis
Evidence that elevated plasma zinc is a clinically meaningful treatment target
Assessment of route compatibility (topical product versus a systemic condition)
TGA Product Information warnings and contraindications for safety screening
Any preclinical or clinical studies directly examining adapalene and plasma zinc
Disclaimer

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