it·ra·con·a·zole ( t r -k n -z l)n. A broad-spectrum antifungal agent administered orally to treat systemic fungal infections and onychomycosis. |
itraconazole
kon´zol´), n brand name: Sporanox;
drug class: antifungal, systemic;
action: inhibits cytochrome P-450 enzyme's blocking synthesis of essential membrane sterols in fungal organism;
uses: blastomycosis, histoplasmosis.
itraconazole
Sporanox
Pharmacologic class: Synthetic triazole
Therapeutic class: Antifungal
Pregnancy risk category C
FDA Boxed Warning
• Don't administer capsules to treat onychomycosis in patients with evidence of ventricular dysfunction, such as current or previous heart failure. If heart failure signs or symptoms occur during therapy, discontinue drug.
• Concurrent use of cisapride, dofetilide, levacetylmethadol (levomethadyl), pimozide, or quinidine with itraconazole capsules or oral solution is contraindicated. Itraconazole is a potent CYP3A4 inhibitor and may raise blood levels of drugs metabolized by this pathway. Serious cardiovascular events (including QT prolongation, torsades de pointes, ventricular tachycardia, cardiac arrest, and sudden death) have occurred in patients taking these drugs concurrently with itraconazole.
Action
Prevents ergosterol synthesis in fungal cell membranes, altering membrane permeability
Availability
Capsules: 100 mg
Oral solution: 10 mg/ml
⊘Indications and dosages
➣ Aspergillosis; blastomycosis; histoplasmosis
Adults: 200 to 400 mg P.O. daily for at least 3 months until patient is cured. In life-threatening infections, loading dose of 200 mg P.O. t.i.d. for 3 days, then 200 to 400 mg P.O. daily until cured.
➣ Esophageal candidiasis
Adults: 100 to 200 mg of oral solution daily, swished in mouth for several seconds and swallowed, for at least 3 weeks; continue for 2 weeks after symptoms resolve.
➣ Oropharyngeal candidiasis
Adults: 200 mg of oral solution daily, swished in mouth for several seconds and swallowed, for 1 to 2 weeks
➣ Onychomycosis; tinea unguium
Adults: For toenails, 200 mg P.O. daily for 12 weeks. For fingernails, 200 mg b.i.d. for 1 week; wait 3 weeks, then repeat dosage for 1 week.
Contraindications
• Hypersensitivity to drug or its components
• Fungal meningitis
• Ventricular dysfunction, heart failure (in onychomycosis use)
• Concomitant use of astemizole, cisapride, dofetilide, lovastatin, midazolam, pimozide, quinidine, simvastatin, or triazolam
• Pregnancy or anticipated pregnancy (in onychomycosis use)
Precautions
Use cautiously in:
• hypersensitivity to other azole derivatives
• renal impairment (with I.V. use), hepatic disorders, achlorhydria, hypochlorhydria
• breastfeeding patients
• children (safety and efficacy not established).
Administration
• Obtain specimens for fungal cultures, as needed, before starting therapy.
• Administer capsule with a full meal.
• Give oral solution without food when possible.
• Be aware that liquid and tablets aren't interchangeable.
| Route | Onset | Peak | Duration |
| P.O. | Slow | 4-6 hr | 4-6 days |
Adverse reactions
CNS: dizziness, headache, fatigue, malaise
CV: peripheral edema, tachycardia, heart failure
EENT: rhinitis
GI: nausea, vomiting, constipation, abdominal pain, flatulence, anorexia, dyspepsia
GU: albuminuria, erectile dysfunction
Hepatic: jaundice, hepatotoxicity (including hepatic failure and death )
Metabolic: hypokalemia
Musculoskeletal: myalgia, bursitis, rhabdomyolysis
Respiratory: pulmonary edema
Skin: flushing, rash, pruritus, urticaria, increased sweating, herpes zoster infection
Other: fever, pain
Interactions
Drug-drug. Alfentanil, antihistamines (minimally sedating agents, such as fexofenadine, loratadine), antineoplastics (busulfan, docetaxel, vinca alkaloids), anxiolytics, benzodiazepines, cyclosporine, delavirdine, digoxin, immunosuppressants, methylprednisolone, protease inhibitors, tacrolimus, tolterodine, tretinoin: increased blood levels of these drugs
Amiodarone, anabolic steroids, androgens, antithyroid drugs, carmustine, chloroquine, dantrolene, daunorubicin, disulfiram, estrogens, gold salts, hormonal contraceptives, hydroxychloroquine, mercaptopurine, methotrexate, methyldopa, naltrexone (with long-term use), valproic acid: increased risk of hepatic damage
Amphotericin B: reduced or inhibited amphotericin B effects
Antacids, anticonvulsants, antimycobacterials, cyclobenzaprine, histamine2-receptor blockers, isoniazid, proton pump inhibitors (such as lansoprazole, omeprazole), reverse transcriptase inhibitors, sucralfate: reduced itraconazole blood level
Antipsychotics, antiarrhythmics (such as quinidine, dofetilide), anxiolytics, astemizole, cisapride: increased risk of serious cardiovascular effects
Calcium channel blockers: increased risk of edema, possible increase in itraconazole's effect
Carbamazepine, carbidopa, levodopa: altered blood levels of these drugs
Didanosine, vinblastine, vincristine, xanthine bronchodilators: decreased efficacy of these drugs
Digoxin: increased digoxin blood level, possible digoxin toxicity
HMG-CoA reductase inhibitors, miconazole: inhibited metabolism of these drugs, increased risk of skeletal muscle toxicity (including rhabdomyolysis)
Macrolide antibiotics: increased itraconazole blood level
Oral hypoglycemics: severe blood glucose decrease
Quetiapine, sildenafil: increased efficacy of these drugs
Warfarin: enhanced anticoagulant effect
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, gamma-glutamyltransferase, serum creatinine: increased levels
Potassium, magnesium: decreased levels
Drug-food. Any food, cola: increased itraconazole blood level
Grapefruit juice: decreased blood level and reduced therapeutic effects of itraconazole
Drug-herbs. Chaparral, comfrey, germander, jin bu huan, kava: increased risk of hepatic damage
Drug-behaviors. Alcohol consumption: toxic reaction, hepatic damage
Patient monitoring
• In patient with hepatic dysfunction, monitor hepatic enzyme levels.
☞ Monitor for signs and symptoms of hepatic dysfunction (jaundice, fatigue, nausea, vomiting, dark urine, pale stools), heart failure, muscle disorder, and pulmonary or peripheral edema.
• Monitor potassium level. Stay alert for hypokalemia.
Patient teaching
• Tell patient he may take capsule with a full meal. If he's using oral solution, advise him to take it without food.
• Inform patient that drug interacts with many other drugs. Advise him to tell all prescribers he's taking it.
☞ Teach patient to recognize and immediately report signs and symptoms of hepatic dysfunction, persistent muscle pain, and heart failure.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Advise female patient of childbearing potential to use effective contraception during and for 1 month after therapy. Caution her not to breastfeed.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.
itraconazole
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