Nystatin

Generic Name

Nystatin

Brand Names

Mycostatin

Nilstat

Nystan

Nyaderm

Nystop

Bio-Statin

Candistatin

Other formulations include oral suspension, lozenges (pastilles), vaginal tablets, topical creams, ointments, and powders

Drug Class

Polyene antifungal

Non-systemic antifungal agent

Primarily fungistatic but can be fungicidal at high concentrations

Mechanism of Action

Nystatin binds to ergosterol, a key component of fungal cell membranes

This binding creates pores in the membrane, leading to increased permeability

As a result, intracellular components (like potassium and other small molecules) leak out, causing cell death

Its mechanism is similar to amphotericin B but with less systemic absorption

Activity is restricted to Candida species and some other yeasts

It is not active against dermatophytes or systemic mycoses due to poor absorption

Indications

Approved Indications

Oropharyngeal candidiasis (oral thrush)

Gastrointestinal candidiasis (e.g., due to antibiotic use, chemotherapy)

Cutaneous candidiasis (skin folds, diaper rash)

Vaginal candidiasis (in some countries)

Prophylaxis of Candida infections in immunocompromised individuals (e.g., HIV, chemotherapy patients)

Denture-associated stomatitis

Off-Label Uses

Fungal otitis externa (as topical adjunct)

Prophylactic use in low birthweight neonates (under specialist guidance)

Treatment of esophageal candidiasis in localized cases

Topical use in perianal and intertriginous candidiasis

Combination creams for mixed bacterial-fungal infections

Dosage and Administration

Oral Candidiasis (Adults and Children)

Oral suspension: 100,000 units/mL

Adults: 400,000–600,000 units (4–6 mL) 4 times daily

Children: 100,000–400,000 units 4 times daily

Infants: 1–2 mL 4 times daily

Hold suspension in mouth as long as possible before swallowing

Treatment duration: 7–14 days or at least 48 hours after lesions resolve

Intestinal Candidiasis

Adults: 500,000 to 1,000,000 units orally 3 times daily

Children: 100,000 to 500,000 units orally 3–4 times daily

Duration varies depending on indication

Cutaneous Candidiasis

Topical cream or ointment: Apply 2–3 times daily to affected areas

Powder form can be used in moist skin folds (axilla, groin, under breasts)

Vaginal Candidiasis (in countries where available)

Vaginal tablets or pessaries: 100,000 to 200,000 units once or twice daily for 14 days

Used in combination with topical or oral treatments in some cases

Prophylaxis in High-Risk Patients (e.g., chemotherapy-induced neutropenia)

Oral suspension: 100,000 units 4 times daily

Usually administered alongside good oral hygiene measures

Pediatric Use

Widely used in neonates and children

Dosage adjusted based on age and weight

Effective for oral and diaper area candidiasis

Administration Notes

Shake oral suspension well before use

Apply topical preparations to clean, dry skin

Do not use topical formulations near eyes

For vaginal tablets, insert deeply at bedtime using applicator

Pharmacokinetics

Absorption

Not absorbed from gastrointestinal tract, skin, or mucous membranes

Remains localized to site of application

Distribution

No systemic distribution

No crossing of blood-brain barrier or placenta

Metabolism and Elimination

Not metabolized

Excreted unchanged in feces when taken orally

Contraindications

Known hypersensitivity to nystatin or any component of the formulation

Avoid vaginal formulations in prepubertal girls unless directed by specialist

Warnings and Precautions

Allergic Reactions

Rare, but hypersensitivity reactions such as rash, pruritus, or angioedema may occur

Prolonged Use

Long-term topical use can result in irritation or secondary infections

Avoid prolonged use without re-evaluation

Avoid in Systemic Infections

Ineffective against systemic fungal infections due to lack of absorption

Do not substitute for amphotericin B or fluconazole in systemic candidiasis

Pediatric Use

Safe when used as directed

For neonates, close monitoring advised, especially when used as prophylaxis

Pregnancy and Lactation

Pregnancy Category A (Australia) / Not assigned by FDA

No evidence of risk in topical or oral use

Poor systemic absorption makes it generally safe in pregnancy

Lactation

Minimal to no absorption expected

Considered safe during breastfeeding when used topically or orally

Avoid application to nipples unless instructed

Adverse Effects

Oral Formulations

Nausea

Vomiting

Diarrhea

Stomach upset

Bad taste or mouth irritation

Topical Formulations

Local irritation

Skin rash

Contact dermatitis

Burning or stinging at site

Rare

Stevens-Johnson syndrome (extremely rare)

Hypersensitivity reactions

Urticaria

Overdose

No significant toxicity from oral or topical overdose due to lack of systemic absorption

Accidental ingestion of large amounts may cause GI upset

Symptomatic treatment only

Drug Interactions

Systemic Drug Interactions

None clinically significant due to poor systemic absorption

Topical Interactions

Avoid concurrent use of other topical agents on same site unless directed

Combination products with corticosteroids may alter local immune response

Antibiotics and Corticosteroids

Antibiotic use may predispose to Candida overgrowth, increasing need for nystatin

Concurrent corticosteroid use may mask symptoms of infection

Use in Special Populations

Elderly

Safe due to minimal systemic absorption

No dose adjustment necessary

Renal and Hepatic Impairment

No systemic metabolism or excretion

No dose adjustment required

Immunocompromised Patients

Frequently used as prophylaxis in patients with AIDS, cancer, or transplant recipients

Monitoring Parameters

Resolution of symptoms: lesions, redness, itching

Adherence to full course of treatment

Watch for recurrence of infection

Monitor for signs of hypersensitivity or local irritation

Formulations Available

Oral Suspension

100,000 units/mL in 60 mL or 120 mL bottles

Sugar-free versions available

Lozenges / Pastilles

100,000 units per lozenge

Dissolve slowly in mouth 4–5 times daily

Topical Cream/Ointment/Powder

100,000 units/g

Cream used for moist skin, ointment for dry, scaly lesions

Powder useful in intertriginous areas prone to maceration

Vaginal Tablets/Pessaries

100,000 to 200,000 units per tablet

Inserted once or twice daily for up to 14 days

Comparative Pharmacology

Nystatin vs Clotrimazole

Both used for Candida infections

Clotrimazole has broader antifungal spectrum and better topical penetration

Nystatin often preferred for oral thrush and in neonates due to minimal absorption

Nystatin vs Fluconazole

Fluconazole is systemically absorbed and used for systemic or esophageal candidiasis

Nystatin remains local and has minimal systemic effects

Nystatin vs Amphotericin B

Similar mechanism but amphotericin B is systemically absorbed and used for invasive infections

Nystatin is safer for topical and mucosal use

Regulatory and Legal Status

Over-the-counter (OTC) in some topical forms

Prescription required for oral suspension and high-dose formulations

Listed on the WHO Model List of Essential Medicines