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Generic name: natamycin ophthalmic

Brand names: Natacyn

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Suspension, Ophthalmic:

Natacyn: 5% (15 mL)


Mechanism of Action

Binds to sterol in fungal cell membrane and changes the cell wall permeability allowing for a reduction of cellular contents



Ophthalmic: Systemic, not expected; Gastrointestinal: Poor


Adheres to cornea, retained in conjunctival fornices; does not produce effective intraocular fluid concentrations

Use: Labeled Indications

Ocular fungal infections: Treatment of fungal blepharitis, conjunctivitis, and keratitis caused by susceptible organisms, including Fusarium solani keratitis.


Hypersensitivity to natamycin or any component of the formulation

Dosage and Administration

Dosing: Adult

Fungal keratitis: Ophthalmic: Instill 1 drop in conjunctival sac every 1 to 2 hours, after 3 to 4 days reduce to one drop 6 to 8 times daily; usual course of therapy is 2 to 3 weeks or until resolution of active fungal keratitis (may be useful to gradually reduce dosage at 4- to 7-day intervals to assure elimination of organism)

Fungal blepharitis or conjunctivitis: Ophthalmic: Instill 1 drop in conjunctival sac 4 to 6 times daily

Dosing: Geriatric

Refer to adult dosing.


Ophthalmic: For topical ophthalmic use only. Shake well before using. Wash hands before and after use. Do not touch tip of applicator to eye or other surfaces.


Store at 2°C to 24°C (36°F to 75°F); do not freeze. Protect from excessive heat and light.

Drug Interactions

There are no known significant interactions.

Adverse Reactions

Postmarketing and/or case reports: Allergic reaction, chest pain, corneal opacity, dyspnea, eye discomfort, edema, hyperemia, irritation and/or pain, foreign body sensation, parasthesia, tearing, vision changes


Disease-related concerns:

  • Epithelial ulceration: Suspension may adhere to epithelial ulcers; retention of the suspension in the fornices occurs regularly.

Special populations:

  • Contact lens wearers: Contains benzalkonium chloride, which may be absorbed by soft contact lenses; remove lenses prior to administration. Contact lenses should not be worn during treatment of ophthalmologic infections (including fungal blepharitis, conjunctivitis, and keratitis).

Other warnings/precautions:

  • Appropriate use: For topical ophthalmic use only. Failure to improve (keratitis) after 7 to 10 days of administration suggests infection caused by a microorganism not susceptible to natamycin; efficacy as a single agent in fungal endophthalmitis has not been established.


Pregnancy Considerations

Animal reproduction studies have not been conducted.

Patient Education

  • Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
  • Have patient report immediately to prescriber vision changes, eye pain, or severe eye irritation (HCAHPS).
  • Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

Source: Wolters Kluwer Health. Last updated December 9, 2016.