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ANTIINFECTIVES FOR SYSTEMIC USE › ANTIMYCOTICS FOR SYSTEMIC USE › ANTIMYCOTICS FOR SYSTEMIC USE › Triazole and tetrazole derivatives
itraconazole
J02AC02
Forms & Strengths
- Capsule: 100 mg
- Oral Solution: 10 mg/mL
- Intravenous: 10 mg/mL (discontinued in many regions)
Adult Dosing
- Blastomycosis and Histoplasmosis: 200 mg orally once daily; up to 200 mg twice daily for life-threatening infections
- Aspergillosis: 200 mg orally once daily
- Onychomycosis (fingernails): 200 mg orally twice daily for 1 week, followed by 3 weeks off, for 2 total courses
- Onychomycosis (toenails): 200 mg orally once daily for 12 consecutive weeks
- Oral solution bioavailability is higher; fasting required for capsules, taken with food for oral solution
Pediatric Dosing
- Safety and efficacy in pediatric patients have not been established
- If used off-label for systemic fungal infections: 2.5 to 5 mg/kg/day divided twice daily
Indications
- Treatment of blastomycosis, histoplasmosis, and aspergillosis in pulmonary and extrapulmonary sites
- Onychomycosis of the toenail and fingernail caused by dermatophytes
- Empiric therapy for febrile neutropenia (off-label)
- Candidiasis (oropharyngeal and esophageal, using oral solution)
Mechanism of Action
- Triazole antifungal agent that inhibits fungal cytochrome P450-dependent enzyme 14-alpha-demethylase
- Depletes ergosterol in the fungal cell membrane, increasing membrane permeability and inhibiting fungal growth
Contraindications
- Co-administration with CYP3A4 substrates that prolong QT interval or cause ventricular arrhythmias (e.g., cisapride, dofetilide, pimozide, quinidine, levomethadyl)
- Co-administration with potent CYP3A4 inducers (e.g., rifampin, carbamazepine, St. John's wort)
- Use in patients with evidence of ventricular dysfunction such as congestive heart failure
- Hypersensitivity to itraconazole or other azole antifungals
Adverse Reactions
- Common: Nausea, vomiting, diarrhea, headache, abdominal pain, dyspepsia, rash
- Serious: Hepatotoxicity (sometimes fatal), congestive heart failure, peripheral neuropathy, QT prolongation
- Metabolic: Hypokalemia, edema
Drug Interactions
- Substrate and potent inhibitor of CYP3A4 and P-glycoprotein
- Co-administration with gastric acid reducers (antacids, H2 blockers, PPIs) significantly decreases capsule absorption
- Increases plasma concentrations of statins (simvastatin, lovastatin), leading to increased risk of myopathy or rhabdomyolysis
- Increases concentrations of certain anticoagulants (warfarin), immunosuppressants (cyclosporine, tacrolimus), and benzodiazepines (midazolam, triazolam)
Curated Content: Needs Vetting Before Put to Clinical Use