Zinc Sulfate

Evidence Level: L5

Predicted Indications: 4

Zinc Sulfate

Pharmacist Assessment Report

Zinc Sulfate: Pharyngitis

One-Sentence Summary

Zinc sulfate is a zinc salt used as a mineral supplement, and the approved indication is not recorded in the local data. The TxGNN model predicts it may be useful for pharyngitis, but the evidence is weak: 1 clinical trial on a related condition (postoperative sore throat) and 1 randomised trial in pharyngitis itself that found no benefit. The evidence level is L5.

Quick Overview

Item	Content
Original Indication	Not recorded in the local data
Predicted New Indication	Pharyngitis
TxGNN Prediction Score	0.9985
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 currently available. Zinc is known to have local antiviral and mucosal-protective effects, and zinc lozenges release zinc ions directly in the oropharynx. Zinc may also support mucosal repair and taste or sensory recovery.

These mechanisms make a role in throat conditions plausible, but the link is indirect. The available studies address postoperative sore throat after intubation and radiation-induced mucosal injury, not infectious pharyngitis. The one randomised trial that studied pharyngitis directly (in radiotherapy patients) did not show a benefit, so the high model score is not supported by clinical findings.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrolment	Key Findings
NCT02405832	Not applicable	Completed	87	Randomised, double-blind, placebo-controlled trial of preoperative zinc lozenges for postoperative sore throat after intubation. This is a related condition, not pharyngitis.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
23720981	2013	RCT	Journal of the Medical Association of Thailand	Zinc sulfate supplementation for radiation-induced oral mucositis and pharyngitis in head and neck cancer patients. No benefit was found for radiation-induced pharyngitis.
20123362	2010	Case report/Observational	Oral Surg Oral Med Oral Pathol Oral Radiol Endod	Recovery from long-lasting post-tonsillectomy taste disturbance; zinc deficiency discussed as a possible factor.

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
600N	Not available	Not available	Not available

At least one valid single-ingredient licence is recorded, and no licences are cancelled.

Safety Considerations

Please refer to the TGA-approved Product Information (PI) for safety information.

Drug Interactions: A total of 100 interactions were found in the interaction screen. Most of those listed are minor (for example, with corticosteroids and several biologic immunosuppressants). Moderate interactions include:

Alendronic acid
Risedronic acid
Ibandronate
Tetracycline
Baloxavir marboxil

These moderate interactions are likely to involve reduced absorption when taken together, so dosing should be separated. Check this against the PI.

Conclusion and Next Steps

Decision: Hold

Rationale: The only randomised trial in pharyngitis itself found no benefit, and the other trial studied postoperative sore throat, a related condition. All direct evidence is therefore negative or absent, and the evidence level is L5. The high TxGNN score is not supported by clinical data.

To proceed, the following is needed:

A controlled trial in infectious pharyngitis showing a clinical benefit
Mechanism of action data
Product Information warnings and contraindications for the Australian product, to allow safety screening
Product, dosage form and indication details for the Australian licence

Disclaimer

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