Nystatin

Introduction Overview

Generic Name

nystatin

Brand Name

Klayesta

Dosage Form

topical powder

Drug Class

Topical antifungals

Pharmacokinetics

Absorption:
Klayesta, formulated as a topical powder containing nystatin, is characterized by negligible systemic absorption when applied to intact skin or mucous membranes. This lack of absorption under clinical conditions limits systemic exposure and consequently minimizes systemic side effects or interactions. Any absorption, if it occurs, is likely minimal and clinically insignificant, as supported by pharmacokinetic studies indicating inability of nystatin to permeate through the intact epidermal barrier.

Distribution:
Given the minimal systemic absorption, nystatin does not achieve systemic distribution. Instead, its antifungal activity is confined primarily to the site of application. This localized activity is beneficial for targeted antifungal treatment with limited systemic exposure.

Metabolism:
Because nystatin is not absorbed into systemic circulation, the drug is not subjected to metabolism in the liver or other organs. Its antifungal action occurs locally at the site of fungal colonization, negating the need for metabolic activation or modification.

Elimination:
Due to negligible absorption, systemic elimination pathways such as hepatic metabolism or renal excretion do not apply. Locally applied nystatin remains at the application site and is typically cleared through sloughing of skin cells or physical removal via washing. This non-systemic elimination route supports its safety profile for topical use.

Overall, the pharmacokinetic profile of Klayesta (topical nystatin powder) supports its use as a localized antifungal agent with minimal risk of systemic toxicity or systemic drug interactions.

Dosage Forms

Available Dosage Forms:
Klayesta is supplied as a topical powder containing 100,000 USP units of nystatin per gram. It is presented in off-white to light yellow powders packaged in plastic squeeze bottles. The available package sizes include 15 g, 30 g, and 60 g bottles for ease of dosing and clinical flexibility.

Dosages for Adults and Adolescents:
The recommended dosing regimen for adults and pediatric patients (from neonates to 16 years) involves applying the powder directly to candidal lesions two or three times daily. For fungal infections of the feet caused by Candida species, the powder should be dusted not only on the skin lesions but also inside all footwear to minimize reinfection and fungal persistence.

Specific Patient Populations:
Pediatric Use: Safety and efficacy have been established in the pediatric population from birth through 16 years, making Klayesta suitable for use in neonates, infants, and children with cutaneous candidiasis.

Geriatric Use: There is insufficient clinical trial data specifically in patients aged 65 and older, although existing clinical experience suggests no difference in response compared to younger adults. However, caution is advised due to potential increased sensitivity.

Pregnancy and Nursing Mothers: Use during pregnancy should be limited to cases where maternal benefit outweighs fetal risk due to lack of definitive studies. Breastfeeding women should use caution as excretion into human milk is unknown.

Storage and Handling:
Klayesta should be stored at controlled room temperature between 20°C and 25°C (68°F to 77°F) and protected from excessive heat. The container should be kept tightly closed to maintain product integrity.

Mechanism Of Action

Nystatin, the active ingredient in Klayesta, is a polyene macrolide antifungal antibiotic derived from Streptomyces noursei. Its primary molecular mechanism involves binding selectively to ergosterol, an essential sterol component of fungal cell membranes. This binding disrupts the integrity and function of the fungal membrane by forming pores or channels, leading to increased permeability.

The increased membrane permeability allows leakage of essential intracellular components such as potassium ions, magnesium ions, and other small molecules, which disrupts fungal cellular homeostasis and results in cell death. This fungicidal activity explains the potent effect of nystatin against yeast and yeast-like fungi, including various Candida species.

At the cellular level, nystatin's ability to target ergosterol differentiates fungal cells from mammalian cells, as mammalian cell membranes contain cholesterol rather than ergosterol. This selectivity contributes to the relatively low toxicity of nystatin in human cells when used topically. Clinically, such a targeted mechanism ensures effective eradication of superficial fungal infections without systemic toxicity.

Comparatively, nystatin shares its mechanism with other polyene antifungals like amphotericin B, though nystatin is largely limited to topical use due to its toxicity profile and poor systemic absorption. Research indicates that Candida albicans rarely develops resistance to nystatin, making it a reliable agent in the management of superficial candidiasis. In contrast, some non-albicans Candida species may develop resistance upon prolonged exposure, which may influence clinical decisions in refractory cases.

In summary, Klayesta’s antifungal action is primarily due to nystatin’s selective ergosterol binding, disrupting fungal membranes and causing cell death, which underpins its efficacy in treating cutaneous and mucocutaneous candidiasis.

Pharmacological Actions

Fungicidal and fungistatic activity against yeasts and yeast-like fungi, particularly Candida albicans and other Candida species.
Binds to ergosterol in fungal cell membranes causing increased membrane permeability and leakage of intracellular contents.
Exhibits negligible systemic absorption, resulting in localized action with minimal systemic toxicity.
No significant activity against bacteria, protozoa, or viruses, highlighting its specificity for fungal pathogens.
Maintains efficacy against Candida albicans with infrequent development of resistance during therapy.
Resistant Candida species (e.g., C. tropicalis, C. krusei) may develop cross-resistance with amphotericin B following exposure.
Acts topically due to poor absorption, suitable for cutaneous and mucocutaneous fungal infections without systemic side effects.
Does not undergo systemic metabolism or renal excretion due to minimal absorption.
Rapid onset of action with repeated application enhances local fungal eradication.
Retains stability and potency in powder form for effective topical administration.
Safe for use in neonates, children, and adults with appropriate dosing.
Compatible with various formulations; in Klayesta, it is combined with magnesium stearate and kaolin as inactive ingredients for topical application.
Does not interfere with normal bacterial flora due to selective antifungal mechanism.
Utilized to prevent fungal colonization in footwear, reducing reinfection risk in dermatophytic infections.

Therapeutic Or Clinical Uses

Treatment of cutaneous candidiasis caused by Candida albicans and other susceptible Candida species.
Management of mucocutaneous candidal infections of skin folds, interdigital spaces, and other moist skin areas.
Topical therapy for fungal infections of the feet (e.g., candidal intertrigo and foot candidiasis).
Adjunctive treatment to reduce fungal contamination in footwear as part of comprehensive antifungal therapy.
Treatment of cutaneous fungal infections in pediatric patients including neonates through adolescence.
Used in patients unable to tolerate systemic antifungal agents due to minimal systemic exposure.
Management of superficial fungal infections where systemic antifungals are contraindicated or unnecessary.
Prophylactic use to prevent fungal colonization in high-risk patients with localized skin candidiasis.
Treatment option for patients with hypersensitivity or adverse reactions to other topical antifungal classes.
Use in patients with immune compromise to treat local candidiasis where systemic spread is not evident.
Treatment of candidiasis in areas covered by occlusive clothing or devices where moisture retention favors fungal growth.
Topical antifungal of choice in cases where rapid symptomatic relief and fungal clearance are desired.
Utility in outpatient and ambulatory care settings due to easy application and favorable safety profile.
Limited to topical use—specifically not indicated for systemic, oral, intravaginal, or ophthalmic infections.
Effective as monotherapy or as part of combination regimens with other antifungals where indicated.

Side Or Adverse Effects

Rare occurrence (less than 0.1%) of allergic reactions including contact dermatitis and hypersensitivity.
Local burning sensation at the site of application after powder administration.
Itching of the treated area which may occur transiently during initial treatment phases.
Development of erythematous rash or eczema potentially related to irritation or sensitivity.
Pain or discomfort upon topical application, especially on broken or inflamed skin.
Rare reports of sensitization leading to discontinuation of therapy.
Possible mild skin dryness or scaling with prolonged use.
No systemic side effects owing to negligible absorption from topical application sites.
Minimal risk of secondary bacterial infection related to local irritation is possible but uncommon.
No reported severe adverse reactions or anaphylaxis linked to Klayesta topical powder in clinical use.
Low antigenic potential attributed to nystatin’s molecular structure compared to other antifungals.
Adverse effects are generally reversible and resolve upon cessation of therapy.
Lack of photosensitivity or phototoxic reactions documented with nystatin topical use.
No reported drug-induced pigmentation or scarring related to topical nystatin powder use.
In case of hypersensitivity, practitioners recommend immediate discontinuation and appropriate medical intervention.

Precautions

Use Klayesta only for topical treatment of cutaneous and mucocutaneous fungal infections; avoid systemic, oral, intravaginal, or ophthalmic application.
Discontinue treatment if irritation, sensitization, or allergic reactions develop and institute appropriate management.
Confirm diagnosis by KOH smear, fungal culture, or other laboratory diagnostic tools before initiation to rule out non-fungal infections.
Advise patients to complete the full prescribed course even if symptoms improve early to prevent recurrence or resistance.
Exercise caution in pregnant women; prescribe only if potential benefits justify potential risks to the fetus due to lack of definitive studies.
Use cautiously in nursing mothers as excretion in human milk is unknown; weigh benefits and risks prior to use.
Monitor for lack of therapeutic response; repeat diagnostic tests to reassess infection and identify resistant organisms.
Avoid contact with eyes and mucous membranes; in case of accidental exposure, rinse thoroughly with water.
Advise patients to keep treated areas clean and dry to enhance treatment efficacy.
Use appropriate protective measures, such as gloves, when applying powder to prevent unintended inhalation or exposure.
Store the product tightly closed and at recommended temperatures to maintain potency and reduce contamination risk.
Inform patients about proper application technique and the importance of avoiding use on large denuded areas or open wounds.
Caution advised when treating elderly due to lack of extensive geriatric data; observe for increased sensitivity.
Reassess treatment strategy if secondary bacterial infection is suspected to avoid complications.
Educate patients about potential mild local side effects and when to seek medical advice.

Warnings

Not to be used for systemic fungal infections; topical use only on intact skin or mucous membranes.
Contraindicated in patients with known hypersensitivity or allergy to nystatin or any components of the formulation.
Discontinue therapy if severe local irritation, rash, or sensitization occurs to prevent worsening adverse effects.
Avoid applying near eyes, mouth, or other mucous membranes to prevent unintended adverse reactions.
Inappropriate use or prolonged application may predispose to superinfection with resistant organisms or bacteria.
Failure to complete full course of therapy may lead to recurrence or persistence of fungal infection.
Excessive heat and improper storage may degrade the product, reducing efficacy and safety.
Not established as safe or effective for use in pregnant or breastfeeding women; assess risk-benefit thoroughly.
Ensure diagnosis of candidiasis to avoid mismanagement of other dermatologic or infectious conditions.
Proper hygiene and care of infected areas are critical to prevent spread and reinfection.
Patients should be warned against sharing topical powders to prevent cross-contamination.
Repeated subculturing studies suggest unlikely resistance development in Candida albicans but possible resistance in other Candida species, necessitating clinical vigilance.
Use with caution if concurrent skin diseases or conditions affecting barrier function are present.
Monitor for rare but possible allergic contact dermatitis which may manifest at the application site.
In event of adverse reaction, cease Klayesta use immediately and provide suitable medical treatment.

Contraindication

Known hypersensitivity or allergy to nystatin or any inactive ingredients in Klayesta powder (magnesium stearate, kaolin).
Patients with history of allergic dermatitis or severe skin sensitivity to topical polyene antifungals.
Not intended for treatment of systemic, oral, vaginal, or ophthalmic fungal infections.
Contraindicated in patients with overgrowth or infection involving non-susceptible fungal species or non-fungal pathogens.
Avoid use if secondary bacterial skin infections are present without appropriate antibacterial therapy.
Not suitable for application on open wounds or severely damaged skin lacking epidermal barrier.
Known or suspected hypersensitivity reactions to topical antifungals in the polyene class.
Contraindicated in cases where diagnostic confirmation of candidal infection is absent or uncertain.
Avoid use in patients with a history of hypersensitivity reactions to related topical antifungal therapies.
Use contraindicated if patient experiences immediate allergic reaction or anaphylaxis to prior nystatin products.
Should not be employed as monotherapy for systemic fungal infections or immunocompromised hosts requiring systemic antifungal therapy.
Patients demonstrating cross-reactivity between nystatin and other polyenes should avoid use.
Contraindicated in ophthalmic fungal infections due to formulation limitations and potential ocular toxicity.
Not for intravaginal use; contraindicated for vaginal candidiasis treatment due to formulation and administration route.
Contraindicated in pediatric patients only if there is documented hypersensitivity to the drug components.

Drug Interactions

Due to minimal systemic absorption, Klayesta has negligible potential for systemic drug interactions.
No known clinically significant interactions with systemic medications due to topical application.
Concurrent use with other topical antifungals or corticosteroids should be evaluated to avoid additive irritation or diminished efficacy.
Avoid concurrent use with irritating topical substances that may enhance local adverse effects.
No reported pharmacokinetic interactions involving hepatic metabolism or cytochrome P450 enzymes.
No known interactions with antibiotics or antiviral agents administered systemically.
Minimal risk of interaction with immunosuppressants or chemotherapeutic agents used systemically.
If used alongside systemic antifungals, no documented antagonism or synergism at topical application site has been noted.
No significant interference with diagnostic laboratory tests has been reported.
Inhalation exposure should be avoided during application to prevent pulmonary irritation and inadvertent interactions.
No contraindicated over-the-counter topical agents identified but caution advised when combining topical medications.
No known interactions with commonly used topical skin care products, moisturizers, or barrier creams.
No evidence that Klayesta modifies the activity of systemic anticoagulants, antihypertensives, or hypoglycemic agents.
Non-interactive with vaccines or biologic therapies according to current data.
Patient counseling should include advising providers of all topical and systemic agents used concurrently for comprehensive assessment.

Preparations Of The Drug

Klayesta is available as a topical powder containing 100,000 USP units of nystatin per gram.
Formulated as an off-white to light yellow powder with inactive ingredients magnesium stearate and light kaolin to facilitate topical application.
Supplied in plastic squeeze bottles with package sizes of 15 grams (NDC 42806-186-15), 30 grams (NDC 42806-186-30), and 60 grams (NDC 42806-186-60) to accommodate different treatment needs.
Package design ensures ease of dispensing and controlled application to affected skin areas.
Manufactured by Epic Pharma, LLC, adhering to FDA standards with ANDA number 210532.
The powder form is advantageous for application in moist lesions and for dusting areas including inside footwear to reduce fungal colonization.
Storage recommendations include maintaining controlled room temperature (20°C to 25°C) and protection from excessive heat and moisture to preserve stability.
Packaging is designed to protect from contamination, maintain sterility, and ensure product integrity during shelf life.
No preservative agents included, relying on packaging integrity and handling instructions to prevent microbial contamination.
Labeling includes instructions for use, contraindications, precautions, and storage information for optimal therapeutic outcome.
The formulation excludes systemic delivery enhancers to maintain localized action and safety profile.
Various bottle sizes offer flexibility in prescribing for acute versus extended therapy durations.
Batch consistency and quality control measures assure uniform potency of nystatin content per gram of powder.
User-friendly format suitable for both patient self-administration and clinical use by healthcare providers.
Frequently compared with other topical antifungal preparations such as creams and ointments, powder form of Klayesta is preferred for wet or intertriginous areas.