What is the recommended treatment and dosage of Terbinafine (terbinafine) for tinea cruris?

Terbinafine Treatment for Tinea Cruris

For tinea cruris, oral terbinafine 250 mg once daily for 1-2 weeks is the recommended treatment, with topical terbinafine 1% cream once daily for 1 week being an effective alternative for localized infections. 1, 2

Oral Terbinafine Treatment

Dosing Recommendations

• For adults and children >40 kg: 250 mg once daily for 1-2 weeks 1, 2
• For children 20-40 kg: 125 mg once daily for 2-4 weeks 2
• For children <20 kg: 62.5 mg once daily for 2-4 weeks 2

Efficacy

• One-week therapy with oral terbinafine 250 mg daily has demonstrated high efficacy in treating tinea cruris with complete mycological cure in clinical studies 1
• Short treatment duration with oral terbinafine improves patient compliance compared to longer treatment regimens 2
• Recent research shows that increasing the dose to 500 mg daily does not provide additional benefit over the standard 250 mg dose 3

Safety Considerations

• Common side effects include gastrointestinal disturbances and dermatological reactions 4
• Terbinafine is contraindicated in patients with:
  • Active or chronic liver disease 4
  • Severe kidney disease 4
  • Lupus erythematosus 2
  • Porphyria 2

Topical Terbinafine Treatment

Dosing Recommendations

• Terbinafine 1% cream applied once daily for 7 days is effective for localized tinea cruris 5, 6
• Topical treatment is appropriate for limited disease without hair follicle involvement 2

Efficacy

• Topical terbinafine 1% cream has demonstrated 84.2% mycological cure rate after a 7-day once-daily regimen 5
• Terbinafine 1% emulsion-gel has shown superior efficacy (94% mycological cure) compared to ketoconazole 2% cream (69% mycological cure) 6
• Terbinafine 1% solution applied once daily for 1 week has shown 65% effective treatment rate for tinea cruris 7

Treatment Algorithm

1. For localized tinea cruris without hair involvement:

   • First-line: Topical terbinafine 1% cream once daily for 7 days 5, 6
   • Alternative: Other topical antifungals like clotrimazole twice daily for 2-4 weeks 2

2. For extensive tinea cruris or recurrent infection:

   • First-line: Oral terbinafine 250 mg once daily for 1-2 weeks 1, 2
   • Consider combination with topical therapy for faster symptom relief 3

3. For treatment failure:

   • Extend oral terbinafine treatment for an additional 2 weeks 2
   • Consider alternative oral antifungals like itraconazole 100 mg daily for 2 weeks if no improvement 2

Important Clinical Considerations

• Complete drying of the crural folds after bathing helps prevent recurrence 2
• Using separate clean towels for drying the groin and other body parts reduces contamination 2
• Covering active foot lesions with socks before wearing undershorts may reduce spread from tinea pedis 2
• The endpoint of treatment should be mycological rather than just clinical cure 2
• Treatment failure may be due to poor compliance, suboptimal drug absorption, or organism insensitivity 2