Comprehensive medication guide to {drug} including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Natacyn (Natamycin) is a polyene antifungal antibiotic formulated as an ophthalmic suspension. It is the only FDA-approved topical antifungal eye medication in the United States. Natacyn is prescribed to treat serious fungal infections of the eye, including fungal keratitis (corneal infection, especially caused by Fusarium solani), fungal blepharitis (eyelid infection), and fungal conjunctivitis. It may also be used off-label for fungal endophthalmitis and infections caused by Candida, Aspergillus, Cephalosporium, and Penicillium species.
Natacyn belongs to the tetraene polyene class of antifungal antibiotics. It works by binding to the sterol component of the fungal cell membrane, which disrupts the membrane's structure and permeability. This causes the fungal cell to lose essential internal contents, ultimately killing the organism. Natacyn is predominantly fungicidal (kills the fungus) rather than merely fungistatic (stopping growth). The suspension is applied directly to the eye, where it acts locally on the infection with minimal systemic absorption.
This is the only commercially available formulation. There are no other strengths or dosage forms on the market.
Natacyn (Natamycin 5% ophthalmic suspension) is the only FDA-approved antifungal eye drop available in the United States, manufactured solely by Alcon Laboratories. Because it is a single-source branded product with no generic alternative, supply chain disruptions can make it difficult to locate. While Natacyn is not currently listed on the FDA Drug Shortage database as of February 2026, its niche market and limited manufacturer base mean intermittent availability issues are common. Many retail pharmacies do not routinely stock it. Patients may need to check specialty pharmacies or have their ophthalmologist's office help source it.
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Natacyn is most commonly prescribed by:
Because fungal eye infections are relatively uncommon and require specialized diagnosis (often with cultures), most Natacyn prescriptions originate from ophthalmology practices. Telehealth prescribing is generally not available for this medication since a thorough in-person eye examination is required.
No. Natacyn is not a controlled substance and has no DEA scheduling. It is a prescription-only antifungal medication with no known potential for abuse or dependence.
Serious but rare side effects may include allergic reactions, corneal opacity, significant eye swelling, persistent eye pain, or breathing difficulties. Contact your doctor immediately if you experience any severe symptoms.
Since Natacyn is the only FDA-approved topical ophthalmic antifungal, alternatives are typically compounded formulations prepared by specialty pharmacies:
These alternatives require a compounding pharmacy and are not commercially manufactured as eye drops. Your ophthalmologist will determine the best treatment based on the specific fungal organism identified.
Natacyn has very few known drug interactions due to its topical ophthalmic administration and minimal systemic absorption.
Always inform your ophthalmologist about all medications and eye drops you are currently using.
Natacyn is a critical medication for patients with fungal eye infections, filling a unique role as the only FDA-approved topical antifungal eye drop in the U.S. Its single-source, brand-only status and high cost ($400–$700 per bottle) can make it challenging to find and afford. If your pharmacy does not have Natacyn in stock, ask your ophthalmologist's office for help sourcing it, contact specialty pharmacies, or use Medfinder to locate availability near you. Patients facing financial hardship should contact Alcon directly at 1-800-757-9195 or visit NeedyMeds for assistance programs.
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