What is the recommended medication and dosage for treating toenail fungus in a 46-year-old male?

Treatment of Toenail Fungus in a 46-Year-Old Male

Terbinafine 250 mg once daily for 12 weeks is the recommended first-line medication for treating toenail fungus in a 46-year-old male. 1, 2

Diagnostic Confirmation Before Treatment

Before initiating treatment, it's essential to confirm the diagnosis of onychomycosis through:

• Potassium hydroxide (KOH) preparation
• Fungal culture
• Nail biopsy in doubtful cases

This confirmation is crucial as only approximately 50% of nail dystrophies are actually caused by fungi 1.

First-Line Treatment: Oral Terbinafine

Terbinafine is the treatment of choice for dermatophyte onychomycosis due to:

• Higher efficacy (70-80% mycological cure rate for toenail infections) 1
• Superior long-term outcomes compared to other antifungals 3
• FDA-approved dosing: 250 mg once daily for 12 weeks for toenail infections 2

Terbinafine works by inhibiting ergosterol biosynthesis in fungi, resulting in both fungistatic and fungicidal effects 3. It achieves high concentrations in the nail matrix within 1 week of starting therapy and persists for at least 30 weeks after treatment completion 3.

Alternative Treatment Options

If terbinafine is contraindicated or not tolerated:

1. Itraconazole (second-line option):

   • 200 mg daily for 12 weeks
   • Efficacy: 45.8% mycological cure rate 1
   • Higher relapse rates compared to terbinafine 4

2. Fluconazole (third-line option):

   • 450 mg once weekly for at least 6 months for toenail infections
   • Lower efficacy than terbinafine or itraconazole
   • May improve compliance due to once-weekly dosing 4

Monitoring and Precautions

When using terbinafine:

• Perform liver function tests before prescribing due to risk of hepatotoxicity 2
• Monitor for adverse effects including:
  • Gastrointestinal complaints (most common)
  • Taste disturbance (can be severe and potentially permanent)
  • Smell disturbance
  • Depressive symptoms
  • Hematologic effects (rare) 2

Treatment Expectations and Follow-up

• Optimal clinical effect is seen months after mycological cure due to the time required for healthy nail outgrowth 2
• Follow-up should be scheduled to assess treatment response
• Recurrence rates are lower with terbinafine (23%) compared to itraconazole (53%) 3

Prevention of Recurrence

To prevent recurrence (which occurs in 40-70% of cases):

• Maintain short, clean nails
• Dry feet thoroughly after bathing
• Wear cotton socks and change them daily
• Apply antifungal powders to shoes and feet
• Avoid sharing nail clippers
• Wear protective footwear in public areas
• Treat concomitant fungal infections promptly 1

Common Pitfalls to Avoid

• Not confirming diagnosis before treatment
• Inadequate treatment duration
• Unrealistic expectations about speed of improvement
• Not addressing predisposing factors like tinea pedis
• Failure to implement preventive measures 1

Terbinafine remains the gold standard treatment for toenail fungus due to its superior efficacy, favorable safety profile, and lower relapse rates compared to other antifungal medications.