What are the treatment options for onychomycosis (nail fungus)?

Treatment Options for Onychomycosis (Nail Fungus)

Oral terbinafine is the first-line treatment for onychomycosis due to its superior efficacy and relatively low risk of side effects, with a recommended dose of 250mg once daily for 12 weeks for toenails. 1

Oral Antifungal Options

First-Line Treatment

• Terbinafine (250mg daily)
  • Mechanism: Inhibits squalene epoxidase, essential for fungal cell wall synthesis 1
  • Duration: 12 weeks for toenails 1, 2
  • Efficacy: Mycological cure rates of 73-94% 1
  • FDA approved specifically for onychomycosis of the toenail or fingernail due to dermatophytes 2
  • Particularly effective against Trichophyton species 1
  • Clinical studies show 71% cure rate at 48 weeks with 12-week treatment course 3

Alternative Oral Treatments

• Itraconazole

  • Dosage: 200mg daily continuous therapy or pulse therapy for 12 weeks 1
  • Mycological cure rate: 45.8% at 48 weeks 1
  • Broader antimicrobial coverage than terbinafine; useful for Candida infections and nondermatophyte molds 1
  • Higher risk of drug interactions than terbinafine 1
  • Avoid in patients with heart failure 1

• Fluconazole

  • Dosage: 150-450mg once weekly for at least 6 months for toenail infections 1
  • Useful alternative when patients cannot tolerate terbinafine or itraconazole 1

• Griseofulvin

  • Dosage: 500-1000mg daily for 12-18 months for toenail infections 1
  • Lower efficacy and higher relapse rates compared to terbinafine and itraconazole 1
  • More effective for Microsporum species infections 1

Topical Treatment Options

Topical therapy should only be used in:

• Superficial white onychomycosis
• Very early distal lateral subungual onychomycosis
• When systemic therapy is contraindicated 1

Topical Options

• Ciclopirox 8% nail lacquer

  • Mycological cure rates of 34% 1
  • FDA approved for mild to moderate onychomycosis without lunula involvement 4
  • Requires monthly removal of unattached, infected nails by a healthcare professional 4
  • Not recommended for concomitant use with systemic antifungals 4

• Amorolfine 5% nail lacquer

  • Approximately 50% efficacy in distal nail infections 1

• Efinaconazole 10% solution

  • Mycological cure rates of 50% 1

• Tioconazole 28% solution

  • Contraindicated in pregnancy 1

Treatment Considerations for Special Populations

• Diabetic patients: Terbinafine preferred due to lower risk of drug interactions 1
• Immunosuppressed patients: Consider topical options when systemic therapy is contraindicated 1
• Pediatric patients: Terbinafine dosing based on weight 1
• Candida onychomycosis: Itraconazole may be more effective than terbinafine 1

Treatment Algorithm

1. Confirm diagnosis before initiating treatment:

   • KOH preparation, fungal culture, or nail biopsy 2

2. Assess severity and type of infection:

   • Mild to moderate without lunula involvement: Consider topical therapy
   • Moderate to severe or with lunula involvement: Oral therapy indicated

3. First-line treatment:

   • Oral terbinafine 250mg daily for 12 weeks (toenails) 1, 3
   • Alternative pulse dosing: 250mg daily for 7 consecutive days every 3 months (not every 4 months) 5

4. If contraindications to terbinafine exist:

   • Itraconazole 200mg daily or pulse therapy
   • Fluconazole 150-450mg weekly

5. For topical-only candidates:

   • Ciclopirox 8% nail lacquer with monthly professional debridement 4
   • Other topical options as listed above

Monitoring and Management of Treatment Failure

• Baseline liver function tests and complete blood count recommended for patients taking terbinafine 1

• Treatment failures may be due to:

  • Poor compliance
  • Poor absorption
  • Immunosuppression
  • Dermatophyte resistance
  • Subungual dermatophytoma
  • Zero nail growth 1

• Management options for treatment failure:

  • Partial nail removal plus antifungal therapy
  • Alternative antifungal drug
  • Complete nail avulsion combined with antifungal therapy 1

Prevention of Recurrence

Onychomycosis has high recurrence rates (40-70%), so preventive measures are essential:

• Keep nails short
• Avoid sharing nail clippers
• Wear protective footwear in public areas
• Apply antifungal powders in shoes and on feet
• Wear cotton, absorbent socks
• Treat concomitant fungal infections 1

Important Caveats

• Terbinafine is contraindicated in severe hepatic impairment 1
• Itraconazole has significant drug interactions and should be avoided in heart failure patients 1
• Topical therapy alone has limited efficacy for extensive infections 1
• The end point of treatment should be mycological rather than clinical cure 1
• Terbinafine reaches the nail plate within 3-18 weeks of starting therapy and remains at stable levels 6