Diphenhydramine Hcl

證據等級: L5

預測適應症: 0 個

Diphenhydramine HCl: Drug Repurposing Evaluation — No Predicted Indications

One-Sentence Summary

Diphenhydramine HCl is a first-generation antihistamine (H1 receptor antagonist) widely used for allergic symptoms, motion sickness, and as a sleep aid. The TxGNN model currently has no predicted new indications for this drug, and the evidence pack contains significant data gaps in regulatory details, safety information, and mechanism of action documentation.

Quick Overview

Item	Content
Original Indication	Antihistamine (allergy, motion sickness, insomnia — specific approved indication text not available in data)
Predicted New Indication	None (no TxGNN predictions available)
TxGNN Prediction Score	N/A
Evidence Level	N/A
Malaysia Market Status	✓ Marketed
Number of Registrations	21
Recommended Decision	Hold

Why is This Prediction Reasonable?

There are currently no TxGNN-predicted new indications for Diphenhydramine HCl, so a mechanistic plausibility assessment cannot be performed at this time.

For background, Diphenhydramine is a first-generation antihistamine that acts as an inverse agonist at the histamine H1 receptor. It also exhibits anticholinergic, antitussive, antiemetic, and mild sedative properties. These multi-receptor activities have historically made it useful across allergy, cold symptoms, motion sickness, and short-term insomnia management.

The absence of TxGNN predictions may result from several factors: (1) the drug’s DrugBank ID was not mapped (recorded as null), which would prevent the knowledge graph from linking Diphenhydramine to its molecular targets and disease associations; (2) incomplete integration of regulatory and pharmacological metadata. Resolving the DrugBank mapping is a prerequisite for generating meaningful repurposing predictions.

Clinical Trial Evidence

Currently no predicted indication available — clinical trial evidence search was not performed.

Literature Evidence

Currently no predicted indication available — literature evidence search was not performed.

Malaysia Market Information

Authorization Number	Product Name	Dosage Form	Approved Indication
(not available)	(not available)	(not available)	(not available)

Note: 21 registrations were identified for Diphenhydramine HCl in the NPRA database, but detailed license information (authorization numbers, product names, dosage forms, and approved indications) was not populated in the evidence pack. This data gap should be remediated by re-querying the NPRA database.

Safety Considerations

Please refer to the package insert for safety information.

Note: Key warnings, contraindications, and drug interaction data were not available in the evidence pack. As a widely used OTC antihistamine, Diphenhydramine’s well-known safety concerns include sedation/drowsiness, anticholinergic effects (dry mouth, urinary retention, constipation), and risk of confusion in elderly patients. A full safety review from the package insert and DrugBank is recommended before any repurposing evaluation proceeds.

Conclusion and Next Steps

Decision: Hold

Rationale: No TxGNN-predicted indications are available for Diphenhydramine HCl. The evidence pack has critical data gaps — missing DrugBank ID mapping, empty license details, and absent safety data — that prevent any meaningful repurposing evaluation.

To proceed, the following is needed:

DrugBank ID mapping: Resolve the null DrugBank ID (Diphenhydramine is DB01075 in DrugBank) to enable knowledge graph linkage
Re-run TxGNN prediction: Once the DrugBank mapping is established, re-execute the KG and DL prediction pipelines
Populate NPRA license details: Re-query the NPRA database to fill in authorization numbers, product names, dosage forms, and approved indication text for all 21 registrations
Safety data collection: Download and parse the package insert to extract key warnings, contraindications, and drug interactions
MOA documentation: Retrieve mechanism of action details from DrugBank (H1 receptor inverse agonist, anticholinergic properties)
Disclaimer

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