Itraconazole Dosing for Tinea Infections
For tinea corporis and tinea cruris, itraconazole should be given at 100 mg orally once daily for 15 days, or alternatively, 200 mg daily for 7 days. 1, 2, 3
Dosing Recommendations by Tinea Type
Tinea Corporis/Tinea Cruris
- First-line dose: 100 mg orally once daily for 15 days 2
- Alternative regimen: 200 mg orally once daily for 7 days 3
- Clinical improvement typically occurs within 2 weeks of starting therapy
- Mycological cure rates of 80-90% can be expected 3-4 weeks after completing treatment 2
Tinea Pedis/Tinea Manuum
- Standard dose: 100 mg orally once daily for 30 days 2
- Higher dose (100 mg) shows faster response and better efficacy (94% vs 80%) compared to lower dose (50 mg) 4
Tinea Capitis
- Second-line therapy (after griseofulvin or terbinafine)
- Recommended dose: 5 mg/kg/day for 2-4 weeks, or 50-100 mg daily for 4 weeks 1
Administration Considerations
- Capsule formulation: Take with food to maximize absorption 1
- Solution formulation: Take on an empty stomach 1
- Preferred formulation: Solution has better absorption characteristics but may cause more gastrointestinal side effects 1
- Avoid concomitant use of medications that decrease stomach acidity 1
Monitoring and Follow-up
- Consider checking itraconazole blood levels after 2 weeks of therapy in cases of treatment failure or when using for extended periods 1
- Therapeutic drug monitoring is particularly important when:
- Adding interacting medications
- Changing dosage
- Assessing adherence
- Treatment failure occurs
Drug Interactions
Itraconazole has significant drug interactions including:
- Enhanced toxicity with warfarin, certain antihistamines, antipsychotics, anxiolytics
- Increased risk of toxicity with digoxin, cisapride, cyclosporine, and statins
- Decreased efficacy when combined with H2 blockers, phenytoin, and rifampicin 1
Treatment Failure Management
If initial treatment fails:
- Consider compliance issues
- Check for adequate absorption (drug levels if available)
- Evaluate for relative insensitivity of the organism
- Rule out reinfection
- Consider extending treatment for an additional 2-4 weeks 1
Special Considerations
- Abbreviated regimens with total doses less than 400 mg have significantly inferior outcomes 5
- For immunocompromised patients, longer treatment courses may be necessary
- The 100 mg daily dose is more effective than 50 mg daily for all types of tinea infections 4
Itraconazole's unique pharmacokinetic profile allows for shorter treatment courses due to its high affinity for the epidermis, where it remains at therapeutic concentrations for up to four weeks after discontinuation of therapy 2.