Is removal of the affected toenail and treatment with terbinafine (generic name) 250mg once daily for 90 days a suitable approach for a 33-year-old male patient with bilateral onychomycosis?

Treatment of Bilateral Onychomycosis with Toenail Removal and Terbinafine

Terbinafine 250 mg daily for 90 days is an appropriate treatment for bilateral onychomycosis in a 33-year-old male patient, and the removal of the affected left big toenail can improve treatment outcomes, especially in cases with significant nail involvement. 1

Treatment Approach for Onychomycosis

Medication Selection

• Terbinafine is the first-line treatment for dermatophyte onychomycosis based on its superior efficacy and tolerability compared to other antifungals 1
• The standard dosage of 250 mg daily for 12 weeks (90 days) for toenail infections is appropriate and FDA-approved 2
• Terbinafine has demonstrated higher mycological cure rates (76-81%) compared to itraconazole (38-49%) in clinical trials 1
• Long-term studies show significantly lower relapse rates with terbinafine (23% mycological relapse) compared to itraconazole (53% mycological relapse) 3

Nail Removal Considerations

• Nail removal in combination with oral antifungal therapy is beneficial in cases with:
  • Significant nail involvement
  • Subungual dermatophytoma (tightly packed mass of fungus)
  • Previous treatment failures 1
• Complete cure rates approaching 100% can be achieved when affected nails are avulsed prior to antifungal treatment 1
• Removal of the affected nail allows better penetration of the antifungal medication to the nail bed 1

Monitoring and Follow-up

Baseline Assessment

• Obtain baseline liver function tests (ALT and AST) before starting terbinafine, especially in patients with:
  • History of liver disease
  • Heavy alcohol consumption
  • Concomitant use of hepatotoxic medications 2
• A complete blood count is also recommended in patients with history of hematological abnormalities 1

Follow-up Schedule

• Re-evaluate the patient 3-6 months after treatment initiation 1
• Consider additional treatment if the disease persists
• The optimal clinical effect is seen some months after mycological cure due to the time required for outgrowth of healthy nail 2

Patient Education

Important Instructions

• Take one 250 mg tablet once daily for 90 days 2
• Can be taken with or without food
• Proper foot hygiene and keeping nails trimmed and clean are essential preventive measures 1
• Wearing protective footwear in public areas (hotels, gyms, swimming pools) to avoid reinfection
• Using absorbent powders and antifungal powders in shoes

Warning Signs

• Advise patient to report immediately any symptoms of:
  • Liver problems: persistent nausea, anorexia, fatigue, right upper abdominal pain, jaundice, dark urine, pale stools
  • Taste or smell disturbance (can be prolonged or permanent)
  • Skin reactions: rash, itching, hives 2

Common Pitfalls and Caveats

• Diagnostic confirmation: Treatment should not be commenced before mycological confirmation of infection 1
• Treatment failure: A consistent failure rate of 20-30% is found in all studies even with terbinafine 1
• Reinfection risk: Onychomycosis is contagious; all infected family members should be treated simultaneously 1
• Footwear management: Consider discarding heavily contaminated footwear or treating with antifungal powders 1
• Drug interactions: Terbinafine has minimal drug interactions compared to azoles, but can affect drugs metabolized by CYP2D6 2
• Intermittent dosing: Pulsed dosing with terbinafine has been shown to be significantly less effective than continuous treatment 4

The combination of nail removal and oral terbinafine represents an optimal approach for treating this patient's bilateral onychomycosis, with the potential to achieve higher cure rates and reduce the likelihood of treatment failure or relapse.