What is the recommended first‑line treatment for oral thrush (candidiasis) in adults and infants?

Treatment of Oral Thrush (Oropharyngeal Candidiasis)

For adults with oral thrush, oral fluconazole 100-200 mg daily for 7-14 days is the first-line treatment, as it is superior to topical agents in efficacy, convenience, and durability of response. 1, 2

First-Line Treatment for Adults

• Oral fluconazole is the drug of choice for oropharyngeal candidiasis, with a dosing regimen of 100-200 mg daily for 7-14 days 1, 2
• Fluconazole is as effective as—and in some studies superior to—topical therapy, with the added benefits of convenience and better patient tolerance 1, 2
• Symptomatic relapses occur sooner with topical therapy compared to fluconazole, particularly in immunocompromised patients 2

Alternative Topical Options for Uncomplicated Cases

For immunocompetent patients with mild, initial episodes, topical agents remain acceptable alternatives, though less preferred: 1, 2

• Clotrimazole troches 10 mg five times daily for 7-14 days 1, 2
• Nystatin suspension 200,000-400,000 units (4-6 mL) four times daily for 7-14 days 1, 3
• Miconazole mucoadhesive tablets once daily 1

Important Caveat on Topical Therapy

• Topical agents are completely ineffective for esophageal candidiasis and should never be used if esophageal involvement is suspected 2
• Do not assume topicals are "safer" to avoid resistance—resistance develops with both topical and systemic therapy 2

Treatment for Infants

For infants with oral thrush, fluconazole 3 mg/kg once daily for 7 days is superior to nystatin and should be the preferred treatment. 4

• Fluconazole achieves 100% clinical cure rates compared to only 32% with nystatin in head-to-head trials 4
• Nystatin suspension dosing for infants: 2 mL (200,000 units) four times daily, with one-half of the dose placed in each side of the mouth using a dropper, avoiding feeding for 5-10 minutes 3
• For premature and low birth weight infants, 1 mL four times daily is effective 3
• Miconazole gel 25 mg four times daily demonstrates 84.7% cure by day 5 versus 21.2% with nystatin, making it another superior alternative to nystatin 5

Second-Line Options for Fluconazole-Refractory Disease

If thrush persists after 7-14 days of appropriate fluconazole therapy: 1, 2

• Itraconazole oral solution 200 mg daily for 7-14 days (effective in ~67% of fluconazole-refractory cases) 1, 2
• Posaconazole oral suspension 400 mg twice daily for 28 days (effective in 75% of azole-refractory cases) 1, 2
• Amphotericin B oral suspension 1 mL (100 mg/mL) four times daily for refractory disease 1, 2

Agents to Avoid

• Do not use ketoconazole or itraconazole capsules as alternatives to fluconazole—they have variable absorption and are significantly less effective 1, 2

Critical Considerations Before Treatment

Before initiating therapy, evaluate for: 2

• Immunocompromised states (HIV, diabetes, corticosteroid use, chemotherapy) that may explain treatment failure 2
• Denture-related disease requiring thorough denture disinfection for definitive cure 2
• Non-albicans Candida species or azole-resistant strains in cases of treatment failure 2

When to Suspect Esophageal Involvement

If the patient has severe throat pain with painful swallowing (odynophagia), assume esophageal candidiasis and treat with systemic therapy. 2

• Esophageal candidiasis requires fluconazole 200-400 mg daily for 14-21 days (not the 7-14 day course used for oropharyngeal disease alone) 1, 2
• Topical agents cannot reach therapeutic concentrations in the esophageal mucosa and will fail 2
• A diagnostic trial of fluconazole is appropriate before performing endoscopy, as most patients will have symptom resolution within 7 days 2

Duration and Monitoring

• Continue treatment for at least 48 hours after symptoms disappear and cultures demonstrate eradication of Candida 3
• For fluconazole, the typical course is 7-14 days for oropharyngeal disease and 14-21 days for esophageal disease 1, 2
• Most patients respond within 48-72 hours of initiating appropriate therapy 1

Common Pitfalls to Avoid

• Never use topical therapy for esophageal candidiasis—it will fail 2
• Do not overlook dentures—denture-related candidiasis requires disinfection of the prosthesis for definitive cure 2
• For immunocompromised patients, favor fluconazole over topicals due to significantly lower relapse rates 2
• Do not use fluconazole capsules interchangeably with itraconazole capsules—itraconazole solution is better absorbed, but fluconazole remains superior overall 2