Home Drug Guide Itraconazole

Drug Guide

Generic Name

Itraconazole

Brand Names Sporanox, Onmel, Tolsura

Classification

Therapeutic: Antifungal

Pharmacological: Imidazole Antifungal

FDA Approved Indications

Treatment of fungal infections including histoplasmosis, blastomycosis, aspergillosis, onychomycosis, and other systemic fungal infections

Mechanism of Action

Itraconazole inhibits fungal cytochrome P450 14α-demethylase, decreasing ergosterol synthesis which impairs fungal cell membrane formation.

Dosage and Administration

Adult: Dosage varies based on infection; typically, 200 mg once or twice daily. For onychomycosis, typically 200 mg once daily for 12 weeks.

Pediatric: Use is limited; dosing based on weight and age. Consult specific guidelines.

Geriatric: Use with caution; monitor liver function. Dosage adjustments may be necessary.

Renal Impairment: Use with caution; no specific dosage adjustment recommended but monitor closely.

Hepatic Impairment: Use with caution; consider lower doses due to hepatic metabolism.

Pharmacokinetics

Absorption: Variable; enhanced with acidic gastric pH, take with food.

Distribution: Widely distributed, including skin, nails, lungs, and CSF.

Metabolism: Primarily hepatic via CYP3A4 enzyme.

Excretion: Excreted mainly in feces, some in urine.

Half Life: approximately 30-40 hours.

Contraindications

Hypersensitivity to itraconazole or other azole antifungals.
Concomitant use with certain medications like terfenadine, astemizole, cisapride (due to risk of QT prolongation).

Precautions

Liver disease, heart failure, or arrhythmias. Use cautiously in pregnancy and lactation. Monitor liver function and cardiac status.

Adverse Reactions - Common

Gastrointestinal upset (nausea, diarrhea) (Frequent)
Nausea, vomiting, abdominal pain (Common)

Adverse Reactions - Serious

Liver toxicity (hepatitis, liver failure) (Uncommon)
QT prolongation, arrhythmias (Rare)
Heart failure worsening (Rare)

Drug-Drug Interactions

Rifampin, certain statins, oral hypoglycemics, cyclosporine, certain benzodiazepines, QT prolonging drugs

Drug-Food Interactions

Gastric acid-suppressing agents may reduce absorption.

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor liver function tests, renal function, and cardiac status. Assess for signs of systemic fungal infections.

Diagnoses:

Risk for hepatotoxicity
Risk for cardiac arrhythmias

Implementation: Administer with food to enhance absorption; monitor for adverse effects; educate patient on signs of liver toxicity and cardiac issues.

Evaluation: Evaluate clinical response, monitor laboratory tests regularly, ensure patient adherence.

Patient/Family Teaching

Take medication with food or after meals.
Report signs of liver problems (jaundice, dark urine, fatigue).
Avoid QT-prolonging drugs and herbal supplements without medical advice.
Do not stop medication abruptly.

Special Considerations

Black Box Warnings:

Heart failure risk, especially in patients with pre-existing heart disease.

Genetic Factors: CYP3A4 interactions can alter drug levels.

Lab Test Interference: May affect liver function tests.

Overdose Management

Signs/Symptoms: Nausea, vomiting, dizziness, abnormal ECG changes.

Treatment: Supportive care; activated charcoal if ingestion was recent; no specific antidote.

Storage and Handling

Storage: Store at room temperature, away from light and moisture.

Stability: Stable under recommended conditions for the duration of the shelf life.