What are the treatment options for toenail fungus?

Treatment of Toenail Fungus

Oral terbinafine 250 mg daily for 12 weeks is the first-line treatment for toenail onychomycosis, with superior efficacy, fungicidal properties, and the strongest evidence base. 1, 2, 3

Diagnostic Confirmation Required

• Always confirm the diagnosis with laboratory testing before initiating treatment - use KOH preparation, fungal culture, or nail biopsy to avoid treating non-fungal nail conditions 3, 4
• The most common cause of treatment failure is incorrect diagnosis made on clinical grounds alone without mycological confirmation 2

Treatment Algorithm

For Most Cases (Moderate to Severe Disease)

Oral terbinafine is the preferred first-line treatment:

• Dosing: 250 mg once daily for 12 weeks for toenails (6 weeks for fingernails) 1, 2, 3
• Efficacy: Highest cure rates among all antifungal agents with fungicidal activity against dermatophytes 1
• Evidence strength: Grade A recommendation, Level 1+ evidence 2

Alternative oral option - Itraconazole:

• Dosing: 200 mg twice daily for 1 week per month (pulse therapy), with 3 pulses for toenails 1
• Preferred for: Candida infections (92% cure rate vs. 40% with terbinafine) and non-dermatophyte molds including Scopulariopsis and Aspergillus 1
• Take with food for better absorption 1

For Limited Disease Only

Topical therapy should ONLY be used when:

• Superficial white onychomycosis (SWO) affecting only the nail surface 5, 2
• Very early distal lateral subungual onychomycosis (DLSO) with <80% nail plate involvement and no lunula involvement 5, 2
• Systemic antifungals are contraindicated 5, 2

Topical options (in order of preference):

1. Amorolfine 5% nail lacquer:

   • Apply once weekly for 6-12 months after filing diseased nail 5
   • Approximately 50% effectiveness for distal nail infections 5, 1, 2
   • Side effects: local burning, pruritus, erythema (rare) 5

2. Ciclopirox 8% nail lacquer:

   • Apply once daily for up to 48 weeks 5, 4
   • Mycological cure: 34% vs. 10% with placebo 5, 1, 4
   • Clinical cure: only 8% vs. 1% with placebo 5
   • Side effects: periungual erythema 5

Special Populations

Diabetic Patients

• Terbinafine is strongly preferred due to lower risk of drug interactions and hypoglycemia compared to itraconazole 1, 2
• Onychomycosis is a significant predictor for foot ulcers in diabetics, making treatment particularly important 1

Immunosuppressed Patients

• Terbinafine or fluconazole preferred over itraconazole due to fewer interactions with antiretrovirals and immunosuppressants 1, 2

Pediatric Patients

• Pulse itraconazole: 5 mg/kg/day for 1 week every month - 2 months for fingernails, 3 months for toenails 5, 1
• Terbinafine (weight-based): 62.5 mg/day if <20 kg, 125 mg/day for 20-40 kg, 250 mg/day if >40 kg 5, 1
• Pediatric cure rates are higher (88-100%) than adults 5, 1

Monitoring and Safety

For Terbinafine:

• Baseline liver function tests and complete blood count recommended 1
• Monitor for headaches, taste disturbances, gastrointestinal symptoms 1
• May exacerbate psoriasis or cause subacute lupus syndrome 1
• Watch for drug interactions with tricyclic antidepressants, SSRIs, atypical antipsychotics, beta blockers, and tamoxifen 6

For Itraconazole:

• Contraindicated in heart failure 1
• Requires surveillance of liver function with prolonged therapy or hepatotoxic medications 1
• Multiple drug interactions due to cytochrome P450 inhibition 2

Adjunctive Measures

• Nail debridement: Remove as much diseased nail as possible by filing before each topical application 5
• Monthly professional nail removal of unattached infected portions enhances treatment response 4, 6

Prevention of Recurrence

Recurrence rates are 40-70%, requiring preventive strategies: 1, 2

• Wear protective footwear in public places 1, 6
• Use absorbent and antifungal powders in shoes 1
• Keep nails short 1
• Avoid sharing nail clippers 1
• Consider prophylactic topical amorolfine weekly after cure - significantly reduces recurrence following oral terbinafine 7

Common Pitfalls to Avoid

• Using topical therapy for extensive disease - this results in predictable failure; oral therapy is required 2
• Underdosing or insufficient treatment duration - complete the full 12-week course for toenails 2
• Not confirming diagnosis before treatment - leads to treatment failure and unnecessary medication exposure 2, 3
• Ignoring drug interactions - particularly problematic with itraconazole 2

Second-Line Options (When First-Line Fails or Contraindicated)

• Fluconazole: Less effective than terbinafine or itraconazole for dermatophytes, but useful when other agents contraindicated due to fewer cytochrome P450 interactions 1, 8
• Griseofulvin: Only 30-40% mycological cure rate, requires 12-18 months for toenails - use only when other agents unavailable 1, 2