What Is Fusafungine? Definition and What Research Reports

Fusafungine (also spelled fusafungin) is an antimicrobial compound of fungal origin that was formulated as a metered-dose spray for the nose and throat. Chemically it belongs to the enniatin family — cyclic hexadepsipeptides, meaning ring-shaped molecules built from alternating amino-acid and hydroxy-acid residues. It is produced by the fungus Fusarium lateritium (strain 437), isolated from rice. Because it was applied topically to mucosal surfaces rather than swallowed or injected, it was usually described in the literature as a local or topical anti-infective with reported anti-inflammatory properties, and it was studied mainly in acute upper respiratory tract infections. Marketing authorisations across the European Union were withdrawn in 2016. This page is for educational purposes only and is not medical advice; consult a licensed physician for any question about a medicine or a health condition.

Where the Molecule Comes From and What Class It Belongs To

Fusafungine is a natural product rather than a synthetic drug designed at a bench. Depsipeptides such as the enniatins are assembled by fungal non-ribosomal peptide synthetases, which is why they contain ester bonds alongside the amide (peptide) bonds found in ordinary proteins. That structural feature — a macrocyclic ring rather than a linear chain — makes the molecule lipophilic and membrane-active, and it is the reason fusafungine is grouped with ionophoric peptide antibiotics rather than with beta-lactams or macrolides.

In peptide-research vocabulary, the term is used in three ways:

• As a named example of a fungal cyclic depsipeptide that reached the pharmacy shelf, cited when authors describe the enniatin class.
• As a topical/locally acting anti-infective, contrasted with systemic antibiotics in prescribing and stewardship research.
• As a regulatory case study, because its European withdrawal generated pharmacovigilance work on what happened to prescribing afterwards.

It is not a "research peptide" in the sense of an experimental analogue circulating in grey markets; it was a licensed pharmaceutical product with decades of clinical publication behind it.

Quick Reference

What the Published Literature Reports

The clinical literature on fusafungine is dominated by European trials and observational programmes in acute upper respiratory infection. A double-blind, placebo-controlled, parallel-group study of fusafungine nasal spray in rhinosinusitis was conducted in 20 patients and is reported in the 2002 Arzneimittel-Forschung paper; the small sample size is itself a notable feature of the evidence base. In pharyngitis, a 2002 study examined therapeutic efficacy and clinical acceptability of fusafungine in follicular pharyngitis, while a separate 2002 report assessed efficacy and acceptability in adult patients with upper respiratory tract infections, framing the product as a local treatment for both nose and throat.

Researchers also pooled data across studies: a 2004 pooled analysis in Rhinology examined the efficacy of fusafungine in acute rhinopharyngitis. A broader narrative appraisal, published in 2004 under the title "How to improve current therapeutic standards in upper respiratory infections: value of fusafungine", positioned the compound within then-current treatment standards. Readers comparing these sources should note that several were sponsored-era efficacy papers published in the same period, and that the pooled analysis draws on the same body of trials rather than independent replication.

Post-Tonsillectomy Research

A second cluster of studies looked at the perioperative period after tonsil surgery. A 2004 paper in the International Journal of Pediatric Otorhinolaryngology examined the effect of fusafungine on post-operative pain and wound healing after pediatric tonsillectomy. A 2002 German-language report in Laryngo-Rhino-Otologie also addressed fusafungine after tonsillectomy, and a 2004 Polish-language paper described application of fusafungine in the perioperative period in patients after tonsillectomy. These were small, setting-specific investigations rather than large multicentre surgical trials.

Prescribing and Antibiotic-Stewardship Research

Because fusafungine was applied locally, several authors asked whether its availability changed how often systemic antibiotics were prescribed. A 2003 analysis of antibiotic prescribing patterns among French general practitioners for upper respiratory tract infections examined the impact of fusafungine on rates of systemic antibiotic prescription, and a 2003 French-language paper in Presse Médicale addressed the impact of fusafungine on antibiotic prescribing in rhinopharyngitis. The mirror image of that question was asked after the product disappeared: a 2019 pharmacovigilance impact study in the European Journal of Clinical Pharmacology examined the effect of fusafungine's withdrawal from the market on prescribing of antibiotics and other alternative treatments in Germany. Taken together, these papers make fusafungine a recurring example in discussions of whether topical options displace or merely accompany systemic antibiotic use.

Safety: What Studies Report

Tolerability was assessed within the clinical programmes rather than in dedicated toxicology publications indexed here. A 2003 multicentre study in Poland, the PROFIL programme, was explicitly designed as an efficacy and safety assessment of fusafungin in the treatment of acute upper respiratory tract infections in adults. Other trials in the set framed their outcomes in terms of "acceptability" alongside efficacy, as in the 2002 report on efficacy and acceptability in adults with upper respiratory tract infections. The eventual European regulatory action in 2016 followed concerns raised about serious hypersensitivity reactions associated with the inhaled product; that regulatory conclusion is a matter of public agency record rather than a finding from the trials summarised above, and the papers listed here do not themselves quantify it. The 2019 German pharmacovigilance impact study treated the withdrawal as its starting point and measured what prescribers used instead.

How the Term Is Used Today

In current writing, "fusafungine" most often appears in three contexts. First, in natural-product chemistry, as a marketed example of an enniatin-type cyclodepsipeptide, useful when explaining why ring-shaped fungal peptides behave differently from ribosomally made ones. Second, in antimicrobial stewardship literature, where the prescribing studies above are cited in arguments about substitution effects. Third, in regulatory and pharmacovigilance teaching, as an illustration of a long-marketed product withdrawn on benefit–risk grounds after decades of use — with the post-withdrawal prescribing question answered empirically by the 2019 German study.

Anyone reading the older efficacy literature should keep publication era in mind. Most of the trials cited on this page appeared between 2002 and 2004, many in journals with a regional or sponsor-linked profile, and several are available in English only as translated abstracts. No dosing information is reproduced here because the purpose of this entry is definitional. Again, this page is for educational purposes only and is not medical advice; questions about treatment of an infection belong with a licensed physician.

References

• The effect of fusafungine on post-operative pain and wound healing after pediatric tonsillectomy (International Journal of Pediatric Otorhinolaryngology, 2004)
• How to improve current therapeutic standards in upper respiratory infections: value of fusafungine (Current Medical Research and Opinion, 2004)
• [Fusafungine after tonsillectomy] (Laryngo-Rhino-Otologie, 2002)
• [Efficacy and safety assessment program of fusafungin in the treatment of acute upper respiratory tract infections in adults (PROFIL): multicenter study in Poland] (Polski Merkuriusz Lekarski, 2003)
• Therapeutic efficacy and clinical acceptability of fusafungine in follicular pharyngitis (Current Medical Research and Opinion, 2002)
• Antibiotic prescribing patterns of French GPs for upper respiratory tract infections: impact of fusafungine on rates of prescription of systemic antibiotics (American Journal of Respiratory Medicine, 2003)
• Effect of withdrawal of fusafungine from the market on prescribing of antibiotics and other alternative treatments in Germany: a pharmacovigilance impact study (European Journal of Clinical Pharmacology, 2019)
• Efficacy and acceptability of fusafungine, a local treatment for both nose and throat infections, in adult patients with upper respiratory tract infections (Current Medical Research and Opinion, 2002)
• Topical treatment of rhinosinusitis with fusafungine nasal spray. A double-blind, placebo-controlled, parallel-group study in 20 patients (Arzneimittel-Forschung, 2002)
• Efficacy of fusafungine in acute rhinopharyngitis: a pooled analysis (Rhinology, 2004)
• [The impact of fusafungine on the prescription of antibiotics in the treatment of rhinopharyngitis] (Presse Médicale, 2003)
• [Application of the fusafungine in perioperative period in patients after tonsillectomy] (Polski Merkuriusz Lekarski, 2004)