Natamycin
Anti-infective · Rx
Trade namesNatacyn
Drug classAntifungal, polyene
Strength5% suspension
AvailabilityRx
Mechanism of actionPolyene macrolide binding ergosterol in the fungal cell membrane, causing leakage. The only FDA-approved topical ophthalmic antifungal; best for filamentous fungi (Fusarium, Aspergillus).
Indication / reason for useFungal blepharitis, conjunctivitis and keratitis, especially Fusarium keratitis (often contact-lens or vegetative-trauma related).
Usual adult dosingKeratitis: 1 drop q1-2h for 3-4 days, then 6-8×/day for 14-21 days; taper on response.
PreservativeBAK 0.02%
Contact lensesNo lens wear; fungal keratitis is frequently lens-associated and needs specialist management.
Common / important adverse effectsPoor corneal penetration (works best on surface disease), adherent granules on the ulcer, irritation, redness.
Contraindications & cautionsHypersensitivity.
Pregnancy / lactationLimited data.
Practice notesRefer suspected fungal keratitis for scraping/culture and confocal microscopy; deep infection may need topical voriconazole/amphotericin or oral azoles.
Chair-side reference only. Dosing, contraindications and pregnancy guidance here are not exhaustive. Confirm against the current prescribing information and the patient’s full history before prescribing or advising.