Phenylephrine

Evidence Level: L4

Predicted Indications: 2

Phenylephrine

Pharmacist Assessment Report

Phenylephrine: From Allergic Rhinitis and Nasal Decongestion to Nasal Cavity Disease

One-Sentence Summary

Phenylephrine is an alpha-1 adrenergic agonist originally used to relieve nasal congestion and related conditions such as allergic rhinitis, the common cold and pharyngitis. The TxGNN model predicts it may be effective for nasal cavity disease, but the support is limited: no registered clinical trials and 5 publications (mostly indirect or low-tier) are available. The prediction overlaps heavily with existing indications, so it is best treated as a research question rather than a new repurposing opportunity.

Quick Overview

Item	Content
Original Indication	Allergic rhinitis, vasomotor rhinitis, pharyngitis, common cold, rhinitis, nasopharyngitis, conjunctivitis (atopic, papillary, vernal), headache disorder, hemorrhoid, proctitis (the India licence records contain no approved-indication text)
Predicted New Indication	Nasal cavity disease
TxGNN Prediction Score	0.9997
Evidence Level	L4 (L5 would apply to model prediction alone; indirect literature exists, but no completed trials)
India Market Status	Listed in a compiled Indian medicine price dataset (at least 20) – CDSCO approval status is not included in this data
Number of Listed Products	at least 20
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available in the data compiled for this report. Based on known pharmacology, phenylephrine is an alpha-1 adrenergic agonist. It constricts the blood vessels of the nasal mucosa, which reduces swelling, congestion and mucosal bleeding.

This is closely aligned with its established uses in rhinitis, nasopharyngitis and the common cold. “Nasal cavity disease” is a broad category that largely overlaps with these existing indications, which likely explains the very high TxGNN score. It therefore adds little repurposing novelty.

The literature does point to a few niche uses: a topical vasoconstrictor to improve the surgical field in endoscopic sinus surgery, and a component of combination nasal sprays (for example, Polydexa with phenylephrine). The evidence for these is indirect or consists of small clinical or experimental reports.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
40899890	2025	Experimental and clinical evaluation	Vestnik otorinolaringologii	Safety and efficacy evaluation of Polydexa spray with phenylephrine (a combination with an aminoglycoside antibiotic) in acute rhinosinusitis; aims to support reduced systemic antibiotic use
37970776	2023	Review	Vestnik otorinolaringologii	Pathogenesis-based approach to treating inflammatory diseases of the nose and paranasal sinuses, including reduction of mucosal hyperaemia and swelling
37184554	2023	Clinical diagnostic article	Vestnik otorinolaringologii	Endoscopic assessment of the nasal mucosa after topical anti-inflammatory and antibacterial therapy, including Polydexa with phenylephrine
25133491	2014	RCT (triple-blind)	PLoS One	Topical tranexamic acid and bleeding during endoscopic sinus surgery in chronic rhinosinusitis; phenylephrine relevance is indirect
7378007	1980	Case report	Arch Ophthalmol	Toxic reactions after intranasal cocaine, with one patient also reacting to intranasal phenylephrine; a safety signal in hypertensive or sympathomimetic-treated patients

India Market Information

All 20 registrations are valid single-ingredient licences. The records contain no approved-indication text. The table lists 5 of them.

Authorization Number	Product Name	Dosage Form	Approved Indication
64687	Dexcare Syrup	Syrup, 100 ml bottle	Not stated in the records
252407	Zuricof DX Syrup	Syrup, 60 ml bottle	Not stated in the records
117227	Korf D Syrup	Syrup, 100 ml bottle	Not stated in the records
116618	Koffrio Tablet DT	Dispersible tablet, strip of 10	Not stated in the records
117200	Kofno-Plus Softgel Capsule	Soft gelatin capsule, strip of 10	Not stated in the records

Safety Considerations

Contraindications (TxGNN model output, not label text): the TxGNN model (deep learning) links phenylephrine to contraindications in several disease groups; these associations may reflect similarities the model learned between related diseases, not biological evidence:
- Cardiovascular: hypertension and hypertensive disorder
- Hepatic and renal: liver failure, liver disease, kidney disease
- Respiratory: COPD
- Neurological and psychiatric: epilepsy, insomnia, psychotic disorders including schizophreniform and schizoaffective disorder
- Endocrine: hypothyroidism, myxedema, Addison disease, adrenocortical insufficiency
- Gastrointestinal: gastric ulcer, peptic ulcer disease, gastritis, inflammatory bowel disease, pancreatitis, gallbladder disease
- Other: porphyria, thrombocytopenia, dermatitis herpetiformis
Drug Interactions: 180 interactions were identified, all of the ones listed are rated Moderate. The main groups are:
- Antidiabetic agents: acarbose, glimepiride, glipizide, glyburide, insulin, SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin), GLP-1 agonists (exenatide, dulaglutide)
- Anticholinergics: atropine (ophthalmic), hyoscyamine, clidinium
- Sympathomimetic anorectic: diethylpropion
Literature safety signal: a 1980 case report describes reactions to intranasal phenylephrine, and the sympathomimetic effect is a concern in patients with hypertensive cardiovascular disease.

Please refer to the package insert for label warnings and contraindications, as these were not available.

Conclusion and Next Steps

Decision: Hold

Rationale: The predicted indication largely overlaps with phenylephrine’s existing nasal decongestant uses, so it offers little novelty. The supporting evidence is indirect or low-tier, with no registered trials. Label safety data are also missing. Two other predictions (acute laryngopharyngitis, trigeminal autonomic cephalalgia) are weaker: the first has no evidence at all, and the second rests on diagnostic pupillometry studies, not therapeutic benefit.

To proceed, the following is needed:

Package insert warnings and contraindications from the India regulator (currently a blocking gap for safety screening)
Mechanism of action data from DrugBank
Approved-indication text for the India licences
Prospective or controlled clinical data in specific nasal cavity diseases (for example, use during endoscopic sinus surgery) that goes beyond current approved uses
Cardiovascular safety assessment for hypertensive and other at-risk populations
Disclaimer

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