What is the recommended dose of terbinafine (antifungal medication) for tinea pedis (fungal infection of the foot)?

Terbinafine Dosage for Tinea Pedis

For tinea pedis, oral terbinafine should be administered at 250 mg once daily for 1 week, which provides similar efficacy to longer courses of topical treatments with faster clinical resolution. 1

Oral Terbinafine Treatment

Adult Dosing

• Oral terbinafine: 250 mg once daily for 1 week 1, 2
  • This short course provides high efficacy with mycological cure rates of >80% 2
  • Offers faster clinical resolution compared to topical treatments 1
  • Similar mycological efficacy to itraconazole 100 mg when given over a 2-week duration 1

Pediatric Dosing (based on weight)

• <20 kg: 62.5 mg daily 3
• 20-40 kg: 125 mg daily 3

• 40 kg: 250 mg daily (adult dose) 3

Topical Terbinafine Options

If oral therapy is contraindicated or for milder cases:

• Terbinafine 1% cream: Apply once or twice daily for 1 week 4
  • Achieves mycological cure rates of >90% 4
  • More effective than 4 weeks of clotrimazole 1% cream 4
• Terbinafine 1% emulsion gel: Apply once daily for 5 days 5
  • Provides 86% effective treatment rate and 97% mycological cure rate 5

Treatment Selection Considerations

Advantages of Oral Terbinafine

• Fungicidal action (kills fungi rather than just inhibiting growth) 2
• Residual effect in tissue after treatment cessation 2
• Short treatment duration improves compliance 1
• High efficacy against common causative organisms (T. rubrum and T. mentagrophytes) 1

Safety Profile

• Generally well-tolerated in both adults and children 1
• Most common side effects: gastrointestinal disturbances and rashes 3
• Potential rare adverse events: isolated neutropenia and liver failure (typically in those with preexisting liver disease) 1
• Contraindicated in severe hepatic impairment 3

Treatment Failure Management

If initial treatment fails:

1. Consider compliance issues, poor absorption, or reinfection 1
2. If clinical improvement but positive mycology: continue therapy for additional 2-4 weeks 1
3. If no clinical improvement: switch to second-line therapy (itraconazole 100 mg daily for 2 weeks) 1

Prevention Strategies

• Thorough drying between toes after bathing 1
• Daily changes of socks 1
• Regular cleaning of footwear 1
• Use of foot powder after bathing (shown to reduce T. pedis rates from 8.5% to 2.1%) 1
• Wearing protective footwear in public areas 3
• Applying antifungal powders in shoes 3

Special Considerations

• Diabetes and obesity are risk factors for tinea pedis and may require more aggressive treatment 1
• For interdigital type tinea pedis: 7-day course of terbinafine 250 mg/day achieves 93.5% cure rate 6
• For chronic moccasin-type tinea pedis: 6-week course may be needed (59% cure rate at 6 weeks, 65% at 8 weeks) 7

Terbinafine's superior efficacy, short treatment duration, and good safety profile make it the treatment of choice for tinea pedis, with oral therapy preferred for faster resolution and more complete eradication of infection.