Natamycin

Mechanism-of-action class: Ergosterol Synthesis Inhibitors.

• NATACYN™ (natamycin ophthalmic suspension) 5% is indicated for the treatment of fungal blepharitis, conjunctivitis, and keratitis caused by susceptible organisms including Fusarium solani keratitis. As in other forms of suppurative keratitis, initial and sustained therapy of fungal keratitis should be determined by the clinical diagnosis, laboratory diagnosis by smear and culture of corneal scrapings and drug response.ICD-10: H10.9

• NATACYN™ (natamycin ophthalmic suspension) 5% is contraindicated in individuals with a history of hypersensitivity to any of its components.contraindicated

SHAKE WELL BEFORE USING. The preferred initial dosage in fungal keratitis is one drop of NATACYN™ (natamycin ophthalmic suspension) 5% instilled in the conjunctival sac at hourly or two-hourly intervals. The frequency of application can usually be reduced to one drop 6 to 8 times daily after the first 3 to 4 days. Therapy should generally be continued for 14 to 21 days or until there is resolution of active fungal keratitis. In many cases, it may be helpful to reduce the dosage gradually at 4 to 7 day intervals to assure that the replicating organism has been eliminated. Less frequent initial dosage (4 to 6 daily applications) may be sufficient in fungal blepharitis and conjunctivitis.

The following events have been identified during post-marketing use of NATACYN ™ (natamycin ophthalmic suspension) 5% in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. The events, which have been chosen for inclusion due to their seriousness, frequency of reporting, possible causal connection to NATACYN™ (natamycin ophthalmic suspension) 5%, or a combination of these factors include: allergic reaction, change in vision, chest pain, corneal opacity, dyspnea, eye discomfort, eye edema, eye hyperemia, eye irritation, eye pain, foreign body sensation, parethesia, and tearing.

Pregnancy: Animal reproduction studies have not been conducted with natamycin. It is also not known whether natamycin can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. NATACYN ™ (natamycin ophthalmic suspension) 5% should be given to a pregnant woman only if clearly needed.

• Oct 30, 1978NDANDA050514Harrow Eye

1. 1Drug Ineffective10227%
2. 2Condition Aggravated7720%
3. 3Off Label Use6317%
4. 4Somnolence4211%
5. 5Eye Pain4010%
6. 6Abdominal Distension3910%
7. 7Persistent Genital Arousal Disorder3910%
8. 8Vomiting3910%
9. 9Abdominal Pain3810.0%
10. 10Appendicitis379.7%
11. 11Appendicolith379.7%
12. 12Ascites379.7%
13. 13Nausea379.7%
14. 14Dry Mouth369.4%
15. 15Ventricular Fibrillation369.4%

Recent PubMed references pinned to Natamycin as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Apo-Transferrin Modified Natamycin-Loaded Liposomes Improve the Prognosis of Fungal Keratitis via Enhanced Antifungal and Anti-Inflammatory Activities.
  International journal of nanomedicine · 2026 · Hu L, Luan J, Liu X, et al.
  PMID 42232486DOI 10.2147/IJN.S595236
• Development of natamycin@halloysite nanotubes-loaded soy protein isolate/sodium alginate films for blueberry preservation.
  International journal of biological macromolecules · 2026 · Shen C, Qian Z, Liu R, et al.
  PMID 41941912DOI 10.1016/j.ijbiomac.2026.151858
• A neutrophil membrane-biomimetic drug delivery system enhances the antifungal and anti-inflammatory efficacy of natamycin for fungal keratitis.
  Biomaterials advances · 2026 · Tong Z, Duan H, Zhang L, et al.
  PMID 41671926DOI 10.1016/j.bioadv.2026.214761
• Malassezia pachydermatis Acquires Resistance to Polyenes in the Laboratory Model.
  Pathogens (Basel, Switzerland) · 2025 · Czyżewska U, Chmielewska S, Bartoszewicz M, et al.
  PMID 41305398DOI 10.3390/pathogens14111162
• Towards elucidating the solar instability of the anti-fungal food preservative natamycin: insights from spectroscopy.
  Physical chemistry chemical physics : PCCP · 2025 · Wrathall NJ, Eller J, Barker JE, et al.
  PMID 41186152DOI 10.1039/d5cp03071d
• Cost-effective natamycin production by Streptomyces lydicus JCK-6019 via solid-state fermentation and development of a bioproduct with fungicidal and plant growth-promoting activities.
  Pest management science · 2026 · Luo F, Park AR, Kim JC, et al.
  PMID 41139932DOI 10.1002/ps.70318
• Enhancement of natamycin production in Streptomyces gilvosporeus through heavy ion beam mutagenesis and global transcription machinery engineering.
  Journal of biotechnology · 2025 · Xu Y, Wang L, Hu W, et al.
  PMID 41046981DOI 10.1016/j.jbiotec.2025.09.017
• Two Cases of Curvularia geniculata Keratitis Successfully Treated with Natamycin-Based Therapy.
  Mycopathologia · 2025 · Fukuto A, Miyako F, Hara T, et al.
  PMID 40944879DOI 10.1007/s11046-025-00997-9

The 10 most recently updated of 14 ClinicalTrials.gov registrations naming Natamycin as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Fungal Ulcer Treatment Augmented With Natamycin and Cyclosporine A
  Recruiting · Phase 3 · Interventional · 150 enrolled · University of California, San Francisco
  NCT06658002updated 2026-06-05
• Rose Bengal Electromagnetic Activation With Green Light for Infection Reduction
  Completed · Phase 3 · Interventional · 330 enrolled · University of California, San Francisco
  NCT05110001updated 2026-01-30
• Trial to Evaluate the Efficacy And Safety of IVIEW-1201 In the Treatment of Fungal Keratitis
  Not yet recruiting · Phase 2 · Interventional · 60 enrolled · IVIEW Therapeutics Inc.
  NCT06463678updated 2025-10-15
• Mycotic Antimicrobial Localized Injection for Treatment of Corneal Ulcers
  Completed · Phase 3 · Interventional · 70 enrolled · University of California, San Francisco
  NCT02731638updated 2025-09-25
• Cross-linking for Corneal Ulcers Treatment Trial
  Completed · Phase 3 · Interventional · 147 enrolled · University of California, San Francisco
  NCT02570321updated 2025-06-18
• Efficacy and Safety of Natamycin and Lactulose Vaginal Suppositories in Treatment of Vulvovaginal Candidiasis
  Completed · Phase 3 · Interventional · 218 enrolled · Avva Rus, JSC
  NCT06411314updated 2024-05-13
• The Antibiogram and Outcomes of Antimicrobial Regimens in Microbial Keratitis: A Prospective Cohort Study
  Completed · Observational · 123 enrolled · Alexandria University
  NCT05655689updated 2024-01-25
• The Mycotic Ulcer Treatment Trial II: A Randomized Trial Comparing Oral Voriconazole vs Placebo
  Completed · Phase 3 · Interventional · 240 enrolled · University of California, San Francisco
  NCT00997035updated 2019-02-26
• Therapeutic Exploratory Study of Comparing Natamycin and Voriconazole to Treat Fungal Corneal Ulcer
  Completed · Phase 1 · Phase 2 · Interventional · 120 enrolled · University of California, San Francisco
  NCT00557362updated 2018-08-07
• Mycotic Ulcer Treatment Trial I
  Completed · Phase 3 · Interventional · 323 enrolled · University of California, San Francisco
  NCT00996736updated 2018-08-01

Frequently asked questions

How does Natamycin work?

Mechanism-of-action class: Ergosterol Synthesis Inhibitors.

What is Natamycin used for?

According to FDA labeling, Natamycin carries indications including: NATACYN™ (natamycin ophthalmic suspension) 5% is indicated for the treatment of fungal blepharitis, conjunctivitis, and keratitis caused by susceptible organisms including Fusarium solani keratitis. As in other forms of suppurative keratitis, initial and sustained therapy of fungal keratitis should be determined by the clinical diagnosis, laboratory diagnosis by smear and culture of corneal scrapings and drug response.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Natamycin?

Natamycin is classified as Antibiotics, Antiinfectives and antiseptics for local oral treatment, Polyene Antimicrobial, Ergosterol Synthesis Inhibitors, Decreased Cell Membrane Integrity.

What are the brand names for Natamycin?

Natamycin is marketed under brand names including Natacyn.

What are the contraindications for Natamycin?

Natamycin labeling lists contraindications including: NATACYN™ (natamycin ophthalmic suspension) 5% is contraindicated in individuals with a history of hypersensitivity to any of its components.. Always consult the full prescribing information and a clinician.