Natoph5%

Natoph ophthalmic suspension is an antifungal medicine used to treat eye infections caused by susceptible fungi. Its evidence-based uses include:

Established / FDA-approved use

• Fungal keratitis (fungal infection of the cornea) caused by susceptible organisms such as Fusarium solani, Aspergillus species, and Candida species. Natoph ophthalmic suspension is considered a first-line, treatment-of-choice agent for fungal keratitis, particularly filamentous fungal keratitis, and diagnosis should ideally be confirmed by laboratory examination (smear/culture) of corneal scrapings.
• Fungal blepharitis (infection of the eyelids) caused by susceptible fungi.
• Fungal conjunctivitis (infection of the conjunctiva) caused by susceptible fungi.

Adjunct / combination use

• In fungal endophthalmitis (infection inside the eye), Natoph has not been established as effective when used alone; it is generally not used as monotherapy for this indication and specialist-directed combination therapy (with systemic or intravitreal antifungals) is required.
• In deep or severe stromal fungal keratitis that responds poorly to topical therapy, ophthalmologists may add systemic antifungal therapy or consider surgical options (e.g., corneal debridement, therapeutic keratoplasty) alongside Natoph, because ocular penetration of topical Natoph into deeper corneal layers is limited.

Non-ophthalmic use (different context)

Natoph is also used industrially as a food-grade preservative on cheese and cured meat surfaces to inhibit mold growth; this food-preservative use is a separate application from its medical use as an ophthalmic antifungal and is not a use covered by this medicine information.

Each mL of Natamycin ophthalmic suspension contains Natamycin 50 mg (5% w/v) as the active ingredient, in a sterile, preserved aqueous suspension for topical application to the eye. Refer to the specific product package insert for the complete list of inactive/preservative ingredients.

Natoph is a polyene macrolide antifungal antibiotic derived from Streptomyces natalensis. In ophthalmology, it is formulated as a sterile 5% suspension for topical instillation into the eye and is used to treat fungal infections of the cornea, conjunctiva, and eyelids.

Natoph ophthalmic suspension is a yellow topical eye preparation that must be shaken well before each use because it is a suspension, not a solution. It is active against a broad range of yeasts and filamentous fungi commonly implicated in ocular fungal infections, including Fusarium, Aspergillus, Cephalosporium, and Candida species.

Ophthalmic antifungal agent (polyene antibiotic class)

Natamycin is a tetraene polyene antifungal that acts by binding to sterol components (primarily ergosterol) in the fungal cell membrane. This binding alters membrane permeability, causing leakage of essential intracellular components (potassium, other ions, and metabolites), which leads to disruption of fungal cell metabolism and ultimately fungal cell death (fungicidal action).

Natamycin exhibits activity against a wide range of yeasts and filamentous fungi, including Fusarium solani (a common cause of fungal keratitis), Aspergillus, Penicillium, Candida, and Cephalosporium species. Following topical ocular administration, Natamycin penetrates the corneal epithelium, but penetration into the deeper corneal stroma and the anterior chamber is limited, which is why deep or severe infections may require additional systemic therapy.

Natoph ophthalmic suspension is for topical use in the eye only; it must never be injected or taken by mouth. Shake well before use, avoid touching the dropper tip to the eye, and follow the physician's instructions on frequency and duration exactly. See Dosage and Administration for step-by-step instillation instructions.

Because Natoph ophthalmic suspension has minimal to negligible systemic absorption when used as directed, clinically significant systemic drug interactions are not well established.

• Other topical ophthalmic medications: If more than one topical eye medication is being used, wait at least 5-10 minutes between instilling Natoph and any other eye drop to prevent one medication from washing out the other and to allow adequate ocular contact time.
• Contact lenses: Not a drug interaction, but soft contact lenses should not be worn during active fungal eye infection treatment with Natoph, as they may concentrate preservative and interfere with corneal healing.

The most commonly reported side effects of Natoph ophthalmic suspension are local and generally mild:

• Eye irritation, burning, or stinging on instillation
• Eye redness (hyperemia)
• Temporary blurred vision immediately after application (due to the suspension itself)
• A sensation of a foreign body in the eye
• Eye pain or discomfort
• Swelling (edema) of the eyelid or conjunctiva
• Increased tearing

Less commonly, allergic reactions, corneal opacity, or changes in vision have been reported after use of Natoph; rare systemic reactions such as chest discomfort or difficulty breathing have been reported post-marketing but are not clearly established to be caused by the topical drug given its minimal systemic absorption. Patients should notify their physician if any side effect is severe or persistent.

Pregnancy: Adequate and well-controlled studies of Natoph ophthalmic suspension in pregnant women have not been conducted, and animal reproduction studies are also lacking. Natoph should be used during pregnancy only if clearly needed, and only if the potential benefit to the mother justifies the potential unknown risk to the fetus; use should be under the direction of a physician.

Lactation: It is not known whether Natoph is excreted in human breast milk after ophthalmic use. Because systemic absorption after topical ocular administration is minimal, risk to a nursing infant is expected to be low, but caution should still be exercised, and a physician should be consulted before use of Natoph while breastfeeding.

For topical ophthalmic use only. Natoph suspension must not be injected subconjunctivally or introduced into the anterior chamber of the eye.

• If no clinical improvement is observed within 7-10 days of starting Natoph therapy, the infecting organism may be resistant; the diagnosis and treatment plan should be re-evaluated by an ophthalmologist.
• Natoph ophthalmic suspension penetrates poorly into the deeper corneal stroma; severe, deep, or non-responding fungal keratitis may require additional systemic antifungal therapy or surgical intervention under specialist care.
• Avoid wearing contact lenses during an active fungal eye infection treated with Natoph.
• Avoid touching the dropper tip to the eye or any surface to prevent contaminating the remaining suspension.
• Complete the full prescribed course of Natoph as directed by your physician; do not stop, extend, skip doses, or share this medicine with others without medical advice, since incomplete treatment can lead to relapse or antifungal resistance.
• Shake the bottle well before each use, since Natoph is formulated as a suspension and the active ingredient can settle.

Topical ocular overdose of Natoph is unlikely to cause serious systemic toxicity given its minimal systemic absorption, but excess or overly frequent instillation may increase local irritation, redness, or discomfort. If Natoph is accidentally ingested or a significantly excessive amount is instilled, or if severe irritation, allergic reaction, or any concerning symptoms occur, seek immediate medical attention or contact a poison control center/emergency services rather than attempting home treatment.

Store Natoph ophthalmic suspension between 2°C and 24°C (36°F-75°F). Do not freeze. Protect the bottle from light and excessive heat, and keep tightly closed. Keep out of reach of children.

Pediatric use: Safety and efficacy of Natoph ophthalmic suspension in children have not been formally established in controlled clinical trials, although it is used clinically in pediatric fungal keratitis under ophthalmologic supervision using adult-derived dosing principles.

Elderly: No specific dose adjustment of Natoph is required in elderly patients; use as directed by the physician.

Renal/hepatic impairment: No dose adjustment is needed, as systemic absorption of Natoph after topical ocular use is negligible.

Pregnancy/lactation: See Pregnancy and Lactation section for cautious use guidance.

Treatment duration with Natoph ophthalmic suspension for fungal keratitis is typically 14 to 21 days, and therapy should continue until active infection has resolved, as determined by the treating ophthalmologist through clinical examination. For fungal blepharitis or conjunctivitis, duration is individualized based on clinical response. Patients should not stop Natoph early even if symptoms improve, and follow-up examinations are important to confirm cure before discontinuation.

Polyene antifungal antibiotic; ophthalmic anti-infective

Natamycin binds to ergosterol and related sterols in the fungal cell membrane, forming pores that increase membrane permeability. This causes leakage of intracellular potassium and other essential components, disrupting fungal cell metabolism and resulting in fungicidal activity against susceptible yeasts and filamentous fungi.

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Safety and efficacy of Natoph ophthalmic suspension have not been formally established in pediatric controlled trials. However, Natoph is used in clinical practice to treat fungal keratitis, blepharitis, and conjunctivitis in children under the direct supervision of an ophthalmologist, generally following the same dosing frequency principles used in adults, adjusted to clinical response. Parents/caregivers should use Natoph in children only as specifically directed by the treating physician.