Natamycin
Indications
Natamycin sterile ophthalmic suspension is indicated for the treatment of fungal blepharitis, conjunctivitis and keratitis caused by susceptible organisms including Fusarium solani.
Pharmacology
Natamycin is a tetraene polyene antibiotic derived from Streptomyces natalensis. Natamycin probably exerts its antifungal effects by binding to sterols in the fungal cell membrane to produce a change in membrane permeability that allows loss of essential cellular constituents. It possesses in vitro activity against a variety of yeast and filamentous fungi, including Candida, Aspergillus, Cephalosporium, Fusarium and Penicillium. Although the activity against fungi is dose-related, Natamycin is predominantly fungicidal. Topical administration appears to produce effective concentration of Natamycin within the corneal stroma but not in intraocular fluid.
Dosage And Administration
For fungal keratitis: The preferred initial dosage is 1 drop instilled in the conjuntival sac (s) at 1-2 hours interval. The frequency of application can usually be reduced to 1 drop 6-8 times daily after the first 3-4 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 days intervals to assure the replicating fungus has been eliminated.
For fungal blepharitis & conjunctivitis: Less frequent initial dosage, 1 drop 4-6 times daily may be sufficient.
Interaction
May increase spread of fungal eye infection when used with topical corticosteroid.
Contraindications
Natamycin ophthalmic suspension is contraindicated in individuals with a history of hypersensitivity to any of its component.
Side Effects
Eye irritation, eye discomfort, eye edema, conjunctival chemosis and hyperemia has been reported.
Pregnancy And Lactation
Pregnancy Category C. Natamycin sterile ophthalmic suspension should be given to a pregnant woman only if clearly needed.
Lactation: It is not known whether this drug is excreted in human milk. Caution should be exercised when Natamycin is administered to a nursing mother.
Precautions And Warnings
For topical eye use only. Failure of improvement of keratitis following 7-10 days of administration of the drug suggests that the infection may be caused by a microorganism not susceptible to natamycin.
Therapeutic Class
Ophthalmic antibacterial drugs.
Use in special populations
Pediatric: Safety and effectiveness in paediatric patients have not been established.
Storage Conditions
Store in a cool and dry place. Protect from light. Do not freeze. Do not use for longer than one month after first opening of the bottle.