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Natamycin (Ophthalmic)

Prescription
Antifungal (Ophthalmic)
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
1 available
Formulations
1

Mechanism of action

Polyene antifungal that binds to ergosterol in the fungal cell membrane, altering membrane permeability and causing cell death. The only FDA-approved ophthalmic antifungal.

At a glance

Class
Antifungal (Ophthalmic)
Schedule
Prescription
Storage
Store at 2–24°C; do not freeze; discard 28 days after opening

Dosing

🐕

Dog

Used for fungal keratitis and blepharitis
Dose
Route
Ophthalmic
Frequency
q1–8h depending on phase
🐈

Cat

Fungal keratitis is uncommon in cats but occurs with trauma
Dose
Route
Ophthalmic
Frequency
q6–8h
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Other — 1

Strength

Storage

Store at 2–24°C; do not freeze; discard 28 days after opening

Safety

Monitoring parameters

Slit-lamp evaluation of corneal lesionCulture resultsIntraocular pressure
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Interactions

No documented interactions.

Brands

Other markets

Natacyn

FAQs

Frequently asked questions

What is Natamycin (Ophthalmic)?
Natamycin (Ophthalmic) is a antifungal (ophthalmic) used in pets. Polyene antifungal that binds to ergosterol in the fungal cell membrane, altering membrane permeability and causing cell death. The only FDA-approved ophthalmic antifungal.
What is Natamycin (Ophthalmic) used for in pets?
Natamycin (Ophthalmic) is used in veterinary medicine for: Used for fungal keratitis and blepharitis; Fungal keratitis is uncommon in cats but occurs with trauma.
What is the Natamycin (Ophthalmic) dose for dogs?
For dogs, Natamycin (Ophthalmic) is typically dosed as follows — Used for fungal keratitis and blepharitis: undefined undefined Ophthalmic q1–8h depending on phase. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Natamycin (Ophthalmic) dose for cats?
For cats, Natamycin (Ophthalmic) is typically dosed as follows — Fungal keratitis is uncommon in cats but occurs with trauma: undefined undefined Ophthalmic q6–8h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Natamycin (Ophthalmic) need a prescription?
Yes. Natamycin (Ophthalmic) is a prescription medication and should only be administered under veterinary supervision.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

References

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

  • Plumb's Veterinary Drug Handbook
  • Withrow & MacEwen's Small Animal Clinical Oncology
  • Merck Veterinary Manual
  • NRC Nutrient Requirements of Dogs and Cats
  • Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

  • ASPCA Animal Poison Control Center Guidelines
  • AAHA Diabetes Management Guidelines
  • ASPCA Poison Control Guidelines
  • RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

  • EPIC Study (J Vet Intern Med 2016)
  • JVIM FAT CAT Study

Regulatory & approvals — 1

  • CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

  • Washington State University VCPL MDR1 Database

Related medicines

Other medicines in the same class (Antifungal).

Flucytosine
Rx
Converted intracellularly by fungal cytosine deaminase to 5-fluorouracil, which is incorporated into fungal RNA and inhibits thymidylate synthase. Mammalian cells lack cytosine deaminase — selective toxicity.
dogcat
Griseofulvin
Rx
Disrupts mitotic spindle structure by interacting with polymerized microtubules, inhibiting fungal cell division; deposited in keratin precursor cells, making new growth resistant to dermatophyte infection
dogcat
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