Recommended Adult Dosage and Frequency of Itraconazole
The standard adult dosage of itraconazole is 200 mg twice daily, with specific loading and maintenance regimens depending on the infection being treated. 1
General Dosing Principles
Standard Formulations and Administration
- Capsule formulation: Best absorbed when taken with food
- Oral solution: Best absorbed when taken on an empty stomach
- Loading dose: For most indications, 200 mg three times daily for first 3 days is recommended
Absorption Considerations
- Avoid agents that decrease stomach acidity when taking capsule formulation
- Oral solution is preferred when available due to improved absorption characteristics
- Serum level monitoring is recommended after 2 weeks of therapy to ensure adequate drug exposure 1
Indication-Specific Dosing
Allergic Bronchopulmonary Aspergillosis
- Conventional capsule: 400 mg daily in two divided doses for 4 months (maximum 600 mg daily)
- Super bioavailable capsule: 260 mg daily in two divided doses for 4 months (maximum 390 mg daily) 1
- Take conventional capsules with meals to improve absorption
- Take super bioavailable capsules on an empty stomach
Blastomycosis
- Initial therapy: 200 mg three times daily for 3 days (loading dose)
- Maintenance: 200 mg twice daily
- Duration: Total of 6-12 months for mild-moderate disease; at least 12 months for severe disease
- Immunosuppressed patients: May require lifelong suppressive therapy at 200 mg daily 1
Sporotrichosis
- Cutaneous and lymphocutaneous: 200 mg daily for 3-6 months (continue for 2-4 weeks after all lesions have resolved)
- Non-responsive cases: Increase to 200 mg twice daily 1
Onychomycosis
- Continuous therapy: 200 mg daily for 3 months
- Pulse therapy: 200 mg twice daily for 1 week per month for 3-4 months 2, 3
Special Populations
Children
- 10 mg/kg per day (maximum 400 mg daily) 1
Pregnant Women
- Avoid itraconazole during pregnancy due to potential teratogenicity
- Consider alternative antifungal agents 1
Monitoring Recommendations
- Obtain serum drug levels after at least 2 weeks of therapy
- Target trough concentrations >5 μg/mL for systemic infections 4
- Monitor for drug interactions, especially with medications metabolized by cytochrome P450 enzymes
- Monitor liver function tests periodically
Common Pitfalls and Caveats
- Doses >600 mg/day approach upper limits of acceptable dosing for long-term treatment and increase risk of adverse effects 4
- Subtherapeutic levels may lead to treatment failure, especially in immunocompromised patients
- Drug interactions are common and can significantly affect efficacy and safety
- Potential adverse effects include:
- Gastrointestinal disturbances
- Hypokalemia and hypertension at higher doses
- Hepatotoxicity (rare)
- Adrenal insufficiency (with prolonged high-dose therapy)
Remember that itraconazole has significant drug interactions and absorption variability, making therapeutic drug monitoring essential for ensuring treatment success, especially in severe infections.