Cefazolin

證據等級: L5

預測適應症: 10 個

Cefazolin: From Bacterial Infection Prophylaxis to Infectious Otitis Media

One-Sentence Summary

Cefazolin is a first-generation cephalosporin antibiotic established in clinical practice for surgical site infection prophylaxis and treatment of susceptible gram-positive bacterial infections. The TxGNN model predicts it may be effective for Infectious Otitis Media, with 1 clinical trial and 3 publications currently supporting this direction. However, critical antibacterial spectrum gaps against key otitis media pathogens limit the strength of this prediction.

Quick Overview

Item	Content
Original Indication	Not available (no Singapore regulatory registration on record)
Predicted New Indication	Infectious Otitis Media
TxGNN Prediction Score	99.44%
Evidence Level	L3
Singapore Market Status	Not marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not currently available from DrugBank records. Based on established pharmacology, Cefazolin is a first-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). It demonstrates strong activity against gram-positive organisms — particularly methicillin-susceptible Staphylococcus aureus (MSSA), Streptococcus pyogenes, and Streptococcus pneumoniae — but has limited activity against gram-negative organisms such as Haemophilus influenzae and Moraxella catarrhalis.

Infectious otitis media (acute otitis media, AOM) is caused primarily by three pathogens: S. pneumoniae, H. influenzae, and M. catarrhalis. Cefazolin can plausibly cover the S. pneumoniae component, which accounts for approximately 25–30% of bacterial AOM cases. However, it lacks meaningful activity against H. influenzae and M. catarrhalis, which together account for over 50% of bacterial AOM. This represents a critical antibacterial spectrum gap for empiric otitis media treatment. In the specific scenario where AOM is confirmed to involve gram-positive organisms only (e.g., S. pyogenes), the mechanistic rationale is considerably stronger.

The TxGNN prediction likely arises from Cefazolin's established role in treating gram-positive ear and upper respiratory tract infections, and its structural and pharmacological similarity to later-generation cephalosporins that do hold formal otitis media indications (e.g., cefuroxime, cefdinir). In practice, however, Cefazolin's IV-only formulation and incomplete pathogen coverage make it a suboptimal empiric choice for routine AOM treatment compared to oral alternatives with broader spectrum.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT01511107	Phase 2b	Terminated	520	Multicenter double-blind RCT comparing 5-day vs 10-day antibiotic courses in children aged 6–23 months with AOM. The trial was terminated before completion; no efficacy conclusions are available. The reason for early termination has not been disclosed and requires investigation to rule out safety signals.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
39567876	2025	Case Report	Ann Otol Rhinol Laryngol	Describes ceftazidime–cefazolin empiric combination therapy for pediatric Gradenigo Syndrome — a rare complication of petrous apicitis secondary to acute otitis media. Cefazolin contributed gram-positive coverage; authors proposed this combination as an empiric alternative where standard monotherapy is inadequate.
877649	1977	General Review	South Med J	Broad review of cephalosporin use in pediatric infections. Notes the inhibitory efficacy of first-generation cephalosporins against some organisms relevant to pediatric ear infections, but predates modern AOM pathogen characterisation. Historical reference value only.
3742953	1986	Clinical Review	Clin Pharmacy	Case report and literature review of Stevens-Johnson syndrome in a child with concurrent otitis media. Cefazolin appears as part of a complex treatment course, not as a targeted otitis media therapy. Limited direct relevance to the predicted indication.

Singapore Market Information

Cefazolin is currently not registered in Singapore. No active product licences or marketing authorisations are on record with the Health Sciences Authority (HSA).

Safety Considerations

Please refer to the package insert for safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: The sole clinical trial for infectious otitis media was terminated before completion, yielding no efficacy conclusions, and all three supporting publications are case-level or historical reviews with minimal direct relevance. More fundamentally, Cefazolin lacks antibacterial activity against H. influenzae and M. catarrhalis — the two most prevalent AOM pathogens after S. pneumoniae — creating a mechanistic basis too narrow for empiric use in an unselected otitis media population.

To proceed, the following is needed:

Termination reason for NCT01511107: Determine whether early stopping reflected a safety signal, futility finding, or administrative cause before any further clinical development is considered
MOA and DrugBank data: Formal confirmation of spectrum and pharmacodynamics from DrugBank to support mechanistic analysis
Pathogen-stratified strategy: Cefazolin may be appropriate in scenarios confirmed to involve gram-positive pathogens only (e.g., post-culture S. pyogenes AOM); prospective data in this subgroup would be required
Singapore registration pathway: Cefazolin is not registered locally; regulatory filing with HSA would be a prerequisite to any clinical use
Package insert and safety data: TFDA prescribing information should be obtained to complete safety assessment (warnings, contraindications, DDI)
Consider adjacent indications with stronger evidence: Middle ear disease in the surgical prophylaxis context (L2, "Proceed with Guardrails") and urinary tract infection (L3, "Proceed with Guardrails") both present more mechanistically coherent and better-evidenced opportunities within this Evidence Pack
Disclaimer

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