Itraconazole

Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026

Itraconazole is a broad-spectrum triazole antifungal used to treat a range of systemic and superficial fungal infections, including aspergillosis, blastomycosis, histoplasmosis, onychomycosis (nail fungus), and oropharyngeal/esophageal candidiasis. It is fungistatic against most pathogens and is available as capsules, an oral solution, and a delayed-release/enhanced-bioavailability formulation. Its absorption and many of its drug interactions are clinically important: capsule absorption requires gastric acid, while the oral solution is best taken on an empty stomach.

Exploratory record, not a reviewed medical publication.

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In short

What the research says.

A quick, data-only summary. The full evidence, dosing, and sources are below.

Itraconazole is a broad-spectrum triazole antifungal used to treat a range of systemic and superficial fungal infections, including aspergillosis, blastomycosis, histoplasmosis, onychomycosis (nail fungus), and oropharyngeal/esophageal candidiasis. NutriStack rates the supporting evidence as strong. Common adult dosing is Capsules: 200 mg once or twice daily for systemic mycoses; onychomycosis of toenails is typically 200 mg once daily for 12 weeks, or pulse dosing of 200 mg twice daily for 1 week per month for 2 (fingernails) to 3-4 (toenails) cycles. Oral solution: 100-200 mg daily for oral/esophageal candidiasis. Doses above 200 mg/day are usually divided twice daily., though a prescriber sets the actual dose. This profile indexes 4 sources.

What it's good for

Treatment of onychomycosis (fungal nail infection) of the toenails and fingernails^4,1
Treatment of systemic mycoses including blastomycosis and histoplasmosis⁴
Treatment of invasive and non-invasive aspergillosis in patients intolerant of or refractory to amphotericin B
Treatment of oropharyngeal and esophageal candidiasis (oral solution)²

What to watch for

Nausea, vomiting, diarrhea, and abdominal pain
Headache and dizziness
Hepatotoxicity and elevated liver enzymes (rarely serious liver injury)
Coadministration with drugs that prolong the QT interval and are metabolized by CYP3A4 (e.g., cisapride, pimozide, quinidine, dofetilide), due to risk of serious cardiac arrhythmias⁴
Coadministration with certain HMG-CoA reductase inhibitors metabolized by CYP3A4 (lovastatin, simvastatin) due to rhabdomyolysis risk⁴

The bottom line

Evidence rating strong. Most-documented uses: treatment of onychomycosis (fungal nail infection) of the toenails and fingernails, treatment of systemic mycoses including blastomycosis and histoplasmosis, treatment of invasive and non-invasive aspergillosis in patients intolerant of or refractory to amphotericin b. 4 sources indexed (2000–2018), with 0 interaction records on file.

The science

How it works, mechanistically.

Core mechanism

Itraconazole inhibits the fungal cytochrome P450 enzyme lanosterol 14-alpha-demethylase (encoded by ERG11/CYP51), which is required for the conversion of lanosterol to ergosterol. Blocking this step depletes ergosterol, an essential component of the fungal cell membrane, and causes accumulation of toxic methylated sterol precursors. The result is increased membrane permeability and disruption of membrane-bound enzyme function, inhibiting fungal growth. Itraconazole is also a potent inhibitor of human CYP3A4 and of P-glycoprotein, which underlies its extensive drug-interaction profile.^4,1

Class

Triazole antifungal

Absorption

Fat-soluble; take with food

Dosing

Dosing & protocol.

Common range

Capsules: 200 mg once or twice daily for systemic mycoses; onychomycosis of toenails is typically 200 mg once daily for 12 weeks, or pulse dosing of 200 mg twice daily for 1 week per month for 2 (fingernails) to 3-4 (toenails) cycles. Oral solution: 100-200 mg daily for oral/esophageal candidiasis. Doses above 200 mg/day are usually divided twice daily.

Recommended form

Oral capsule (take with food and an acidic beverage) or oral solution (take on an empty stomach); formulation choice depends on indication

Itraconazole is highly lipophilic. Capsule absorption is enhanced by food and requires an acidic gastric environment, so capsules should be taken with a full meal and ideally an acidic beverage (such as a cola); acid-suppressing drugs (proton pump inhibitors, H2 blockers, antacids) markedly reduce capsule absorption. In contrast, the oral solution and certain enhanced-bioavailability capsules (e.g., Tolsura) are best absorbed on an empty stomach. Formulations are not interchangeable on a milligram-per-milligram basis.

Safety

Full safety detail.

Side effects

Nausea, vomiting, diarrhea, and abdominal pain
Headache and dizziness
Hepatotoxicity and elevated liver enzymes (rarely serious liver injury)
Edema and new or worsening congestive heart failure (negative inotropic effect)
Hypokalemia
Rash and pruritus
Peripheral neuropathy (discontinue if it occurs)
Transient or permanent hearing loss (reported)

Contraindications

Coadministration with drugs that prolong the QT interval and are metabolized by CYP3A4 (e.g., cisapride, pimozide, quinidine, dofetilide), due to risk of serious cardiac arrhythmias⁴
Coadministration with certain HMG-CoA reductase inhibitors metabolized by CYP3A4 (lovastatin, simvastatin) due to rhabdomyolysis risk⁴
Coadministration with oral midazolam, triazolam, and certain ergot alkaloids^2,4
Use for treatment of onychomycosis in patients with evidence of ventricular dysfunction such as congestive heart failure or a history of CHF^3,1
Coadministration with certain other CYP3A4 substrates per labeling (e.g., colchicine, eplerenone, fesoterodine in renal/hepatic impairment, and others)⁴
Known hypersensitivity to itraconazole^1,2
Pregnancy when used for onychomycosis^1,3

Sources

Sources, by evidence tier.

Numbered references. Citations throughout the page link here.

Randomized controlled trials

1Continuous versus intermittent (pulse) itraconazole for the treatment of toenail onychomycosisGupta AK, et al · Journal of the American Academy of Dermatology · 2000
Both continuous and pulse itraconazole regimens achieved clinical and mycological cure in dermatophyte toenail onychomycosis, with pulse dosing reducing total drug exposure.

Reviews & position papers

2Pharmacokinetics and dosage adjustment in patients with hepatic dysfunction and oral bioavailability of itraconazole formulationsLindsay J, Mudge S, Thompson GR · Clinical Pharmacokinetics / Antimicrobial Agents and Chemotherapy · 2018
Itraconazole capsule bioavailability depends on an acidic gastric environment and food, while the cyclodextrin oral solution achieves higher and more reliable exposure when taken fasting.
3Itraconazole and congestive heart failure: a review of safety signalsAhmad SR, Singer SJ, Leissa BG · Mayo Clinic Proceedings · 2001
Cases of congestive heart failure were associated with itraconazole, supporting a boxed warning and contraindication of itraconazole for onychomycosis in patients with ventricular dysfunction or CHF.

Reference material

4Sporanox (itraconazole) Capsules US Prescribing InformationJanssen Pharmaceuticals · FDA Label · 2018
Itraconazole is a triazole antifungal that inhibits ergosterol synthesis; capsule absorption requires gastric acidity and is enhanced by food, and the drug is a potent CYP3A4 inhibitor with multiple contraindicated coadministrations.

FAQ

Common questions.

Quick answers about Itraconazole, drawn from the data on this page.

What is Itraconazole?

What is Itraconazole used for?

Commonly cited benefits of Itraconazole include: Treatment of onychomycosis (fungal nail infection) of the toenails and fingernails; Treatment of systemic mycoses including blastomycosis and histoplasmosis; Treatment of invasive and non-invasive aspergillosis in patients intolerant of or refractory to amphotericin B; Treatment of oropharyngeal and esophageal candidiasis (oral solution). NutriStack rates the overall evidence as strong.

What is a typical dose of Itraconazole?

A typical adult dose of Itraconazole is Capsules: 200 mg once or twice daily for systemic mycoses; onychomycosis of toenails is typically 200 mg once daily for 12 weeks, or pulse dosing of 200 mg twice daily for 1 week per month for 2 (fingernails) to 3-4 (toenails) cycles. Oral solution: 100-200 mg daily for oral/esophageal candidiasis. Doses above 200 mg/day are usually divided twice daily.. The commonly recommended form is Oral capsule (take with food and an acidic beverage) or oral solution (take on an empty stomach); formulation choice depends on indication. These are general ranges, not personalized advice; confirm the right dose with a clinician.

What are the side effects of Itraconazole?

Reported side effects include nausea, vomiting, diarrhea, and abdominal pain, headache and dizziness, hepatotoxicity and elevated liver enzymes (rarely serious liver injury), edema and new or worsening congestive heart failure (negative inotropic effect), hypokalemia, rash and pruritus. This is educational information; check with a healthcare professional before use.

How strong is the evidence for Itraconazole?

NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.

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