Ampicillin

證據等級: L5

預測適應症: 10 個

Ampicillin: From Bacterial Infections to Laryngitis

One-Sentence Summary

Ampicillin is a broad-spectrum aminopenicillin antibiotic with a long history of use in treating a wide range of bacterial infections affecting the respiratory tract, urinary tract, and soft tissues. The TxGNN model predicts it may be effective for Laryngitis with a score of 99.97%, supported by 1 related clinical trial and 20 publications — though the majority of this evidence is indirect, with most laryngitis cases being viral in origin and current bacterial cases favouring newer antibiotics. Given the mechanistic plausibility but significant clinical limitations, a cautious "Hold" stance is recommended pending clearer evidence in a bacterial subpopulation.

Quick Overview

Item	Content
Original Indication	Bacterial infections (respiratory tract, urinary tract, soft tissue)
Predicted New Indication	Laryngitis
TxGNN Prediction Score	99.97%
Evidence Level	L3
Singapore Market Status	✗ Not marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Ampicillin is a classic aminopenicillin that works by binding to penicillin-binding proteins (PBPs) on bacterial cell walls, blocking peptidoglycan cross-linking and leading to cell lysis. This mechanism of action makes it effective against organisms that possess a peptidoglycan cell wall — a category that includes the principal pathogens implicated in bacterial laryngitis.

Bacterial laryngitis, particularly its more severe presentations such as acute epiglottitis, paraglottic abscess, rhinoscleroma, and laryngeal actinomycosis, involves organisms including Haemophilus influenzae, Streptococcus pyogenes, Klebsiella rhinoscleromatis, and Actinomyces israelii. Ampicillin retains in vitro activity against penicillin-susceptible strains of all of these pathogens, providing a plausible mechanistic rationale for the TxGNN prediction. Case reports in the literature document the use of penicillin-class antibiotics in managing laryngeal actinomycosis (PMID 30579693, 24930374), consistent with this mechanistic logic.

However, the clinical picture in 2026 is considerably more nuanced. The vast majority of laryngitis episodes are viral, rendering antibiotics ineffective. Among the bacterial minority, H. influenzae type b has been largely suppressed by widespread vaccination, and many residual H. influenzae and Moraxella catarrhalis strains produce β-lactamase, rendering plain ampicillin ineffective. Current guidelines favour ceftriaxone or amoxicillin/clavulanate for bacterial upper airway infections. The high TxGNN score likely reflects the structural proximity of bacterial laryngitis nodes to other ampicillin-susceptible upper respiratory infection nodes in the knowledge graph, rather than a clinically actionable repurposing signal.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT01406275	N/A (Post-marketing)	Completed	363	Post-marketing surveillance of CLAVAMOX® (amoxicillin/clavulanate) in Japanese paediatric patients across multiple indications including laryngitis, tonsillitis, and bronchitis. The study drug is an amoxicillin/clavulanate combination — not plain ampicillin — and ampicillin-specific efficacy data for laryngitis cannot be extracted.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
3977063	1985	Retrospective Cohort	Anaesthesia and Intensive Care	Review of 161 children with acute epiglottitis at a tertiary paediatric hospital; discusses airway management strategies and antibiotic use context for severe bacterial laryngeal infections
1712371	1991	Clinical Trial	J Clin Gastroenterology	Ampicillin (2 g/day) used in 1 of 19 Whipple's disease patients receiving short-term antibiotic treatment; provides limited but direct evidence of ampicillin use in an Actinomyces-related infection context
25944348	2015	Retrospective Cohort	Otolaryngol Head Neck Surg	Examined hospital- and physician-level variation in perioperative antibiotic use for laryngectomy and its relationship to surgical site infection rates; highlights the critical role of antibiotic selection in laryngeal surgical outcomes
39879424	2025	Guidelines Assessment	CoDAS	AGREE II methodological quality assessment of clinical guidelines for managing laryngitis and pharyngitis; identifies current standard-of-care frameworks
35923122	2023	Review + Case Report	Ann Otol Rhinol Laryngol	Historical review of spontaneous laryngeal abscess; notes that such presentations were historically linked to systemic infections (typhoid, syphilis) and that the modern antibiotic era has dramatically reduced their incidence
38145982	2024	Observational	Eur Arch Otorhinolaryngol	Microbiological characterisation and antibiotic susceptibility of neck abscess pathogens in diabetic vs. non-diabetic patients; provides actionable data on selecting β-lactam therapy for deep neck infections
30579693	2019	Case Report	Auris Nasus Larynx	Post-bone marrow transplant laryngeal actinomycosis in a 14-year-old girl; imaging showed a mass mimicking tumour; treated with penicillin-class antibiotics consistent with ampicillin's coverage of Actinomyces
24930374	2014	Case Report	J Voice	Laryngeal actinomycosis in a 74-year-old immunocompromised man with neutropenia; infection resolved after prolonged penicillin-class antibiotic therapy, confirming β-lactam susceptibility of Actinomyces in this rare presentation
8651625	1996	Case Series	Ann Otol Rhinol Laryngol	Rhinoscleroma (Klebsiella rhinoscleromatis) involving the larynx and trachea; early-stage disease treated with tetracycline; laryngotracheal involvement requires surgical intervention — ampicillin is not first-line
12402494	2002	Case Series	Acta Otorrinolaringol Esp	Two cases of paraglottic laryngeal abscesses presenting as a life-threatening emergency; emphasises the need for rapid diagnosis and treatment, with systemic antibiotics as a key component of management

Singapore Market Information

Ampicillin currently has no registered products with the Health Sciences Authority (HSA) of Singapore. The drug is not marketed in Singapore under any licence. Clinicians requiring ampicillin would need to consider importation through the HSA's Special Access Route or use alternative registered aminopenicillins (e.g., amoxicillin).

Safety Considerations

Please refer to the package insert for safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: Despite a high TxGNN prediction score and mechanistic plausibility for bacterial laryngitis, plain ampicillin faces critical clinical barriers: most laryngitis is viral and unresponsive to antibiotics; bacterial cases increasingly involve β-lactamase-producing organisms outside ampicillin's coverage; and current clinical guidelines have already moved on to superior alternatives (ceftriaxone, amoxicillin/clavulanate). There is no Singapore market presence, and all safety data requires independent verification from the package insert.

To proceed, the following is needed:

Mechanism of action data from DrugBank to confirm PBP-binding pharmacology in the context of ENT pathogens
Singapore HSA package insert retrieval for warnings, contraindications, and approved dosing
Local resistance surveillance data for upper respiratory tract pathogens (H. influenzae, S. pyogenes, Moraxella catarrhalis) in Singapore
Prospective case series or retrospective cohort specifically evaluating ampicillin in bacteriologically confirmed laryngitis subtypes where susceptible organisms are likely (e.g., laryngeal actinomycosis, rhinoscleroma)
Regulatory feasibility assessment for importing and prescribing a non-HSA-registered product in this indication
Disclaimer

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