CLASSES
Ophthalmological Anti-infectives
DESCRIPTION
Ophthalmic antifungal agent.
Used to treat fungal blepharitis, conjunctivitis, and keratitis.
Fungicidal against Candida, Aspergillus, Fusarium, Acremonium, and Penicillium species.
COMMON BRAND NAMES
Natacyn
HOW SUPPLIED
Natacyn/Natamycin Ophthalmic Susp: 5%
DOSAGE & INDICATIONS
For the treatment of fungal keratitis.
Ophthalmic dosage
Adults and Geriatric
Initially instill 1 drop topically into the conjunctival sac every 1—2 hours. Application frequency may be reduced to 1 drop topically every 3—4 hours after the first 3—4 days of treatment; however in some cases, application frequency should be gradually reduced at 4—7 day intervals to ensure treatment success. Duration of therapy is 14—21 days or until resolution of active fungal keratitis. Reevaluate patient if improvement is not evident after 7—10 days of treatment.
For the treatment of fungal blepharitis and fungal conjunctivitis.
Ophthalmic dosage
Adults and Geriatric
Instill 1 drop topically into conjunctival sac every 4—6 hours. Duration of therapy should be based on clinical reevaluation and additional laboratory results.
MAXIMUM DOSAGE
Adults
24 drops/day per affected eye.
Geriatric
24 drops/day per affected eye.
Adolescents
Safety and efficacy have not been established.
Children
Safety and efficacy have not been established.
Infants
Safety and efficacy have not been established.
Neonates
Safety and efficacy have not been established.
DOSING CONSIDERATIONS
Hepatic Impairment
No dosage adjustments are needed.
Renal Impairment
No dosage adjustments are needed.
ADMINISTRATION
Ophthalmic Administration
Natamycin is for topical administration to the eyes only; do NOT inject parenterally.
Instruct patient on proper instillation of eye suspension (see Patient Information).
Instruct patient not to wear contact lenses if signs or symptoms of an ocular infection are present.
To prevent contamination, do not touch the tip of the dropper to the eye, fingertips, or other surface.
Shake well before using.
Wash hands before and after use.
Tilt the head back slightly and pull the lower eyelid down with the index finger to form a pouch. Squeeze the prescribed number of drops into the pouch. Close eyes to spread drops.
To avoid contamination or the spread of infection, do not use dropper for more than one person.
STORAGE
Natacyn:
- Avoid excessive heat (above 104 degrees F)
- Do not freeze
- Protect from light
- Store between 36 to 77 degrees F
CONTRAINDICATIONS / PRECAUTIONS
General Information
Use is contraindicated in patients with a known hypersensitivity to natamycin or any other component in the formulation. Some patients with allergies to cheeses may have sensitivity to natamycin, which is used commonly as a preservative food additive in cheeses. Natamycin is classified as a polyene antifungal; thus, administer natamycin with caution in patients with hypersensitivities to other polyene antifungals. Consider discontinuation of therapy in patients developing an allergic reaction during natamycin treatment.
Intramuscular administration, intravenous administration
Natamycin is only indicated for topical administration to the eyes. Take measures to prevent intramuscular administration and intravenous administration of the aqueous suspension.
Herpes simplex virus epithelial keratitis, mycobacterial infection, varicella, viral infection
Natamycin is only indicated for the treatment of ocular fungal infections including fungal blepharitis, conjunctivitis, and keratitis. This product is ineffective in patients with an ocular viral infection such as herpes simplex virus epithelial keratitis, vaccinia, and varicella. In addition, avoid natamycin administration to patients with an ocular bacterial or mycobacterial infection as natamycin exhibits no in vitro antibacterial activity.
Contact lenses
Instruct patients to avoid wearing contact lenses during treatment with natamycin if signs and symptoms of fungal blepharitis, conjunctivitis, or keratitis are present.
Children, infants, neonates
Safety and efficacy of natamycin have not been established in neonates, infants, or children.
Pregnancy
No data are available to determine whether the use of natamycin during pregnancy can cause fetal harm or affect reproduction capacity; however, systemic absorption is not expected following topical ophthalmic administration. Administer natamycin during pregnancy only if clearly needed.
Breast-feeding
According to the manufacturer, it is not known if natamycin is excreted in human milk; however, systemic absorption is not expected following topical ophthalmic administration. Caution is advised when administering natamycin to a nursing woman. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to maternally administered natamycin, health care providers are encouraged to report the adverse effect to the FDA.
ADVERSE REACTIONS
Severe
corneal opacification / Delayed / Incidence not known
Moderate
dyspnea / Early / 0-1.0
chest pain (unspecified) / Early / 0-1.0
superinfection / Delayed / 0-1.0
ocular infection / Delayed / 0-1.0
blurred vision / Early / 10.0
hyperemia / Delayed / Incidence not known
Mild
ocular irritation / Rapid / 1.0-10.0
lacrimation / Early / 1.0-10.0
foreign body sensation / Rapid / 1.0-10.0
paresthesias / Delayed / 0-1.0
ocular pain / Early / Incidence not known
DRUG INTERACTIONS
There are no drug interactions associated with Natamycin products.
PREGNANCY AND LACTATION
Pregnancy
No data are available to determine whether the use of natamycin during pregnancy can cause fetal harm or affect reproduction capacity; however, systemic absorption is not expected following topical ophthalmic administration. Administer natamycin during pregnancy only if clearly needed.
According to the manufacturer, it is not known if natamycin is excreted in human milk; however, systemic absorption is not expected following topical ophthalmic administration. Caution is advised when administering natamycin to a nursing woman. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to maternally administered natamycin, health care providers are encouraged to report the adverse effect to the FDA.
MECHANISM OF ACTION
Natamycin binds to ergosterol, a sterol essential for the stability of fungal cell membranes. As a result of this binding, cell membrane integrity is impaired, causing loss of intracellular potassium and other cellular contents. Natamycin possess dose-related fungicidal activity against a variety of yeast and filamentous fungi. The in vitro antifungal activity of natamycin includes Candida, Aspergillus, Fusarium, Acremonium (previously known as Cephalosporium), and Penicillium species.
PHARMACOKINETICS
Natamycin is administered topically to the eyes. Systemic absorption is not expected following topical administration of natamycin.
Oral Route
Natamycin is not indicated for oral administration; however if accidentally ingested, absorption of natamycin from the gastrointestinal tract is limited.
Other Route(s)
Ophthalmic Route
Following topical administration to the eyes, natamycin produces therapeutic concentrations within the corneal stoma; however, absorption into the intraocular fluid is limited. In animal studies involving rabbits, natamycin concentrations in the aqueous humor and sera were not measurable (sensitivity of no greater than 2 mg/ml). Furthermore, topically administered natamycin is not expected to be absorbed systemically.