Nystatin topical - Drug Monograph

Introduction

Nystatin topical is a polyene antifungal medication used primarily for the treatment of cutaneous and mucocutaneous fungal infections caused by Candida species. First isolated in 1950 from Streptomyces noursei, nystatin has been a cornerstone of antifungal therapy for decades. The topical formulation is available in various preparations including cream, ointment, powder, and topical solution, providing flexibility for different clinical presentations.

Mechanism of Action

Nystatin exerts its antifungal effect by binding to ergosterol, the principal sterol in fungal cell membranes. This binding creates pores in the membrane that disrupt cellular permeability, leading to leakage of intracellular components including potassium ions, nucleotides, and amino acids. The subsequent loss of cellular integrity results in fungal cell death. Nystatin demonstrates selective toxicity toward fungal cells due to its higher affinity for ergosterol than mammalian cholesterol.

Indications

Nystatin topical is FDA-approved for:

• Cutaneous candidiasis
• Mucocutaneous candidiasis
• Intertriginous candidal infections
• Diaper dermatitis with candidal involvement
• Perianal candidiasis
• Oral thrush (using topical suspension)

Off-label uses include:

• Prophylaxis in immunocompromised patients
• Treatment of candidal paronychia
• Angular cheilitis of candidal origin

Dosage and Administration

• Cream/Ointment (100,000 units/g): Apply 2-4 times daily to affected areas
• Powder (100,000 units/g): Apply liberally 2-3 times daily
• Topical solution (100,000 units/mL): Apply 4 times daily to oral lesions

• Clean and dry affected area before application
• Apply thin layer to cover entire affected area and surrounding skin
• Continue treatment for at least 48 hours after symptoms resolve
• Typical treatment duration: 2-4 weeks

• Pediatric: Same dosing as adults
• Geriatric: No dosage adjustment required
• Hepatic/renal impairment: No specific recommendations (minimal systemic absorption)

Pharmacokinetics

Contraindications

• Hypersensitivity to nystatin or any component of the formulation
• History of anaphylactic reaction to polyene antifungals

Warnings and Precautions

• For external use only; avoid ophthalmic use
• Discontinue if irritation or hypersensitivity develops
• Use cautiously in patients with known sensitivity to other antifungal agents
• Not for treatment of systemic fungal infections
• Occlusive dressings may enhance absorption and increase risk of adverse effects

Drug Interactions

No clinically significant drug interactions have been reported due to negligible systemic absorption. However, theoretical considerations include:

• Potential interference with the action of latex condoms and diaphragms (when used vaginally)
• Possible reduced efficacy when used concomitantly with topical corticosteroids on same site

Adverse Effects

• Local irritation
• Burning sensation
• Pruritus at application site
• Erythema
• Contact dermatitis

• Stevens-Johnson syndrome (case reports)
• Acute generalized exanthematous pustulosis
• Hypersensitivity reactions

Monitoring Parameters

• Clinical response after 1-2 weeks of therapy
• Signs of local irritation or hypersensitivity
• Resolution of symptoms
• Signs of superinfection with bacteria or non-susceptible fungi
• Patient compliance with treatment regimen

Patient Education

• Use medication exactly as prescribed
• Complete full course of treatment even if symptoms improve
• Wash hands before and after application
• Avoid covering treated area with tight-fitting clothing unless directed
• Do not use on areas not affected by infection
• Store at room temperature away from moisture
• Report any worsening symptoms, irritation, or rash
• For oral suspension: swish in mouth for several minutes before swallowing
• Avoid eating or drinking for 15-30 minutes after oral administration

References

1. Lexicomp Online. Nystatin (Topical). Wolters Kluwer Clinical Drug Information, Inc.; 2023. 2. American Society of Health-System Pharmacists. AHFS Drug Information. Nystatin topical. Bethesda, MD: ASHP; 2023. 3. Pappas PG, Kauffman CA, Andes DR, et al. Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2016;62(4):e1-e50. 4. FDA Prescribing Information. Nystatin Topical Cream, Ointment, Powder. Revised 2022. 5. Gupta AK, Skinner AR. Management of diaper dermatitis. Int J Dermatol. 2004;43(11):830-834. 6. Sobel JD. Vulvovaginal candidosis. Lancet. 2007;369(9577):1961-1972.