Itraconazole
Also known as: Sporanox · Intrafungol · Itrafungol · itraconazolum · oriconazole · R-51211
Reviewed by the VetSheet Veterinary TeamUpdated May 15, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Malassezia dermatitis | 5 mg/kg PO once daily | PO | q24h | 3 weeks | 🌎 NA |
| Pulse therapy for Malassezia dermatitis | 5 mg/kg for 2 consecutive days per week | PO | 2 consecutive days per week | 3 weeks | 🌎 NA |
| Dermatophytosis | 5 mg/kg PO once daily | PO | q24h | Prolonged course required | 🌎 NA |
| Dermatophytosis (Pulse therapy) | 5 mg/kg PO once daily on an every other week schedule | PO | q24h (pulse) | Three 'pulses' of one week on, one week off | 🌎 NA |
| Blastomycosis | 5 mg/kg PO once daily | PO | q24h | At least 30 days after all signs resolve (total 60-90 days) | 🌎 NA |
| Histoplasmosis | 10 mg/kg daily PO | PO | q24h | At least 30 days after all signs resolve (total at least 90 days) | 🌎 NA |
| Blastomycosis (Alternative) | 5 mg/kg PO once a day or divided twice a day | PO | q24h or q12h | 2-3 months or until active disease is not apparent | 🌎 NA |
| Coccidiomycosis | 5-10 mg/kg PO once daily | PO | q24h | 6-12 months | 🌎 NA |
| Sporotrichosis | 5-10 mg/kg once daily | PO | q24h | 30 days beyond complete resolution of detectable lesions | 🌎 NA |
| Pythiosis or lagendiosis (after lesion resection) | 10 mg/kg PO once daily | PO | q24h | At least 2 months after surgery | 🌎 NA |
| Zygomycosis | 5-10 mg/kg PO q24h | PO | q24h | 3-6 months for non-resectable lesions | 🌎 NA |
| Idiopathic lymphoplasmacytic (chronic) rhinitis (LPR) | 5 mg/kg PO q12h | PO | q12h | Minimum of 3-6 months | 🌎 NA |
| Nasal aspergillosis | 5 mg/kg PO q12h | PO | q12h | 3-6 months | 🌎 NA |
| Coccidioidomycosis | 5-10 mg/kg PO q24h or 5 mg/kg PO q12h | PO | q24h or q12h | — | 🌎 NA |
| General use (fungal infections) | 5 mg/kg | PO | q24h | 4-20 weeks of treatment may be needed, dependent upon culture results | 🌍 EU |
- Malassezia dermatitis: Fair evidence supports recommendation
- Dermatophytosis: Begin taking cultures after 4 weeks. Continue therapy for 2 weeks beyond clinical cure and when 2-3 negative cultures are obtained at weekly intervals.
- Dermatophytosis (Pulse therapy): Toxicity problems are rare with this protocol.
- Blastomycosis: Give with food.
- Histoplasmosis: Give with food. If intestinal histoplasmosis, treat with amphotericin B initially.
- Blastomycosis (Alternative): A loading dose of 10 mg/kg once a day (or divided twice a day) for the first three days may reduce the 'lag' phase.
- Pythiosis or lagendiosis (after lesion resection): Given with terbinafine at 5-10 mg/kg PO q24h.
- Zygomycosis: After aggressive surgical resection or for non-resectable lesions.
- Idiopathic lymphoplasmacytic (chronic) rhinitis (LPR): Has shown dramatic beneficial improvement in some dogs.
- Nasal aspergillosis: May cure up to 60-70% of dogs, although some studies show marginal efficacy.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Histoplasmosis | 10 mg/kg daily PO | PO | q24h | At least 2-4 months | 🌎 NA |
| Cryptococcosis | 50-100 mg per cat per day PO | PO | q24h | Many months (mean 8.5 months) | 🌎 NA |
| Blastomycosis | 10 mg/kg PO once a day or divided twice a day | PO | q24h or q12h | 2-3 months or until active disease is not apparent | 🌎 NA |
| Coccidiomycosis | 5-10 mg/kg PO once daily | PO | q24h | 6-12 months | 🌎 NA |
| Sporotrichosis | 5-10 mg/kg once daily | PO | q24h | 30 days beyond complete resolution of detectable lesions | 🌎 NA |
| Cryptococcosis (mild to moderate, no CNS involvement) | Cats <= 3.5 kg: 50 mg PO once daily or 100 mg PO every other day; Medium/large cats: 100 mg PO once daily | PO | q24h or q48h | 3-12 months | 🌎 NA |
| Coccidioidomycosis | 25-50 mg (total dose) per cat q12-24h | PO | q12-24h | — | 🌎 NA |
| Generalized dermatophytosis (Microsporum canis) | 5 mg/kg PO once daily preferably between meals for 7 days on, 7 days off; repeat 3 times | PO | q24h (pulse) | 5 weeks (treated weeks 1, 3, 5) | 🌎 NA |
| Generalized dermatophytosis (Alternative) | 5 mg/kg PO twice daily or 10 mg/kg | PO | q12h or q24h | Generally 3-5 weeks | 🌎 NA |
| Dermatophyte granuloma | 10 mg/kg PO once daily | PO | q24h | Weeks to months | 🌎 NA |
| Dermatophytosis (Pulse therapy) | 5 mg/kg PO once daily on an every other week schedule | PO | q24h (pulse) | Three 'pulses' of one week on, one week off | 🌎 NA |
| General use (fungal infections) | 5 mg/kg | PO | q24h | 4-20 weeks of treatment may be needed, dependent upon culture results | 🌍 EU |
| Dermatophytosis (Microsporum canis) | 5 mg/kg | PO | q24h | Pulse dosing: 7 days on, 7 days off repeated x3 | 🌍 EU |
- Histoplasmosis: Given with food. Can also be divided twice daily.
- Cryptococcosis: If response inadequate, may add flucytosine.
- Blastomycosis: Cats usually require longer treatment than dogs.
- Cryptococcosis (mild to moderate, no CNS involvement): Give with food. Monitor ALT. Continue until completely normal, then check antigen titer.
- Generalized dermatophytosis (Alternative): Give with food. Give until culture is negative 2 times at two week intervals.
- Dermatophyte granuloma: At least one month beyond clinical resolution and until brush culture is negative x 2.
- Dermatophytosis (Microsporum canis): Authorized in the form of an oral solution. Used successfully to treat ringworm in Persian cats without the need for clipping.
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Blastomycosis (Mice) | 50-150 mg/kg q24h | PO | q24h | — | 🌎 NA |
| Vaginal candidiasis (Rats) | 2.5-10 mg/kg q24h | PO | q24h | — | 🌎 NA |
| Systemic candidiasis (Guinea pigs) | 5 mg/kg q24h | PO | q24h | — | 🌎 NA |
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Fungal infections in Ratites | 6-10 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Fungal diseases | 5-10 mg/kg PO q12-24h | PO | q12-24h | — | 🌎 NA |
| Aspergillosis (Amazon parrots) | 5-10 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
| Aspergillosis (African grey Parrots) | 2.5-5 mg/kg PO once daily | PO | q24h | — | 🌎 NA |
- Fungal infections in Ratites: If neuro signs develop reduce dose or discontinue.
- Fungal diseases: Use with caution in African grey parrots.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Guttural pouch mycosis, mycotic rhinitis or osteomyelitis | 5 mg/kg PO q24h | PO | q24h | — | 🌎 NA |
- Guttural pouch mycosis, mycotic rhinitis or osteomyelitis: Using the oral solution should be sufficient for treatment.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Itraconazole is a synthetic, highly lipophilic oral triazole antifungal agent used extensively in veterinary medicine for the treatment of systemic mycoses (such as aspergillosis, cryptococcosis, blastomycosis, and histoplasmosis) as well as superficial dermatophytosis and Malassezia infections.
Clinical Pearls & Pharmacological Profile:
- Superior Efficacy: It is generally considered more efficacious and has fewer endocrine side effects compared to older imidazoles like ketoconazole, as it does not appreciably suppress mammalian hormone synthesis.
- Tissue Distribution: Because it is highly lipophilic and keratinophilic, it concentrates heavily in the skin, sebum, and pus, making it exceptionally effective for dermatological fungal infections.
- Formulation Matters: The absorption of itraconazole is highly formulation-dependent. Commercially available capsules require an acidic gastric environment and food for optimal absorption. The commercial oral solution contains cyclodextrin to enhance solubility and is best absorbed on an empty stomach.
- Compounding Warning: Compounding from bulk powder is strongly discouraged as it often results in subtherapeutic or undetectable blood levels, which can be fatal in systemic fungal infections.
Mechanism of action
Itraconazole is a fungistatic triazole.
Mechanism of Action:
- Enzyme Inhibition: Itraconazole selectively inhibits the fungal cytochrome P450-dependent enzyme lanosterol 14α-demethylase.
- Pathway Disruption: This inhibition blocks the conversion of lanosterol to ergosterol (the primary sterol in fungal cell membranes) → leads to the accumulation of toxic 14α-methylsterols.
- Membrane Permeability: The lack of ergosterol alters the cellular membrane structure → increases membrane permeability → allows leakage of cellular contents and impairs the uptake of purine and pyrimidine precursors.
- Immunomodulation: Itraconazole also exhibits mild immune-suppressing activity, likely via the suppression of T-lymphocyte proliferation.
Safety & warnings
Contraindications
- Hypersensitivity to itraconazole or other azole antifungals
- Hepatic impairment (relative contraindication)
- Achlorhydria or hypochlorhydria (relative contraindication)
- Reduced cardiac function (relative, due to potential negative inotropic effects)
- Pregnancy
- Liver disease (avoid use if present)
Adverse effects
- Anorexia (most common in dogs)
- Hepatotoxicity (increased ALT, jaundice)
- Ulcerative skin lesions/vasculitis (dogs at high doses)
- Limb edema (dogs at high doses)
- Erythema multiforme (rare)
- Toxic epidermal necrolysis (rare)
- Vomiting
- Weight loss
- Depression (especially in cats and African grey parrots)
- Diarrhoea
- Salivation
- Depression and apathy
- Abdominal pain
- Hepatic toxicosis
- Ulcerative dermatitis
- Limb oedema
- Serious cutaneous drug eruptions (occasional)
- Dose-related suppression of adrenal function
Precautions
Use with caution in patients with hepatic impairment, achlorhydria, or reduced cardiac function (due to potential negative inotropic effects). African grey parrots are extremely sensitive to itraconazole and can develop severe anorexia and depression; reduced dosages or alternative antifungals are recommended. Do not use compounded capsules from bulk powders, as they may not yield an absorbable dosage form, leading to treatment failure in life-threatening infections. Safety during pregnancy is not established (teratogenic and embryotoxic in lab animals at high doses).
Drug interactions
May be antagonistic against Aspergillus or Candida; clinical importance unclear.
May reduce oral absorption of itraconazole; administer itraconazole at least 1 hour before or 2 hours after antacids.
Itraconazole may increase benzodiazepine levels.
Plasma concentrations may be elevated.
Itraconazole may increase levels.
Itraconazole may increase levels.
Increased cisapride levels and possibility for toxicity; concurrent use contraindicated in humans.
May decrease metabolism and increase clomipramine levels.
May inhibit the metabolism of corticosteroids; potential for increased adverse effects.
May inhibit metabolism of cyclophosphamide and its metabolites; potential for increased toxicity.
Increased cyclosporine levels.
May increase digoxin levels; concurrent use considered contraindicated in humans.
May increase fentanyl or alfentanil levels.
Increased gastric pH may reduce itraconazole absorption.
May increase risk for neurotoxicity.
May increase itraconazole concentrations.
May decrease itraconazole levels.
Increased gastric pH may reduce itraconazole absorption.
Increased risk for quinidine toxicity.
May decrease itraconazole levels; itraconazole may increase rifampin levels.
May increase levels; hypoglycemia possible.
May inhibit vinca alkaloid metabolism and increase levels.
May cause increased prothrombin times in patients receiving warfarin or other coumarin anticoagulants.
Extends the activity of methylprednisolone
Inhibits metabolism, potentially leading to toxicity
Inhibits metabolism
Inhibits metabolism
Increases bioavailability and blood levels of ciclosporin (well-documented in cats)
Inhibits metabolism and increases plasma concentrations
Reduces the absorption of itraconazole
Reduces the absorption of itraconazole
Reduces the absorption of itraconazole
Increases plasma concentrations of benzodiazepines
Increases plasma concentrations of vincristine
Datasheet advises against concurrent administration in cats
Datasheet advises against concurrent administration in cats
Monitoring
- Clinical Efficacy
- Liver function tests (monthly ALT recommended with long-term therapy)
- Appetite (anorexia is often the first sign of toxicity)
- Physical assessment for ulcerative skin lesions in dogs
- Liver enzymes (ALT, AST, ALP, Bilirubin) prior to and during prolonged treatment
- Clinical signs of hepatotoxicity (anorexia, vomiting, jaundice)
- Resolution of clinical signs and negative fungal cultures
Pharmacokinetics
Absorption
Highly dependent on gastric pH and presence of food. Empty stomach bioavailability may be <50%; with food, it approaches 100%. The oral solution is better absorbed on an empty stomach and possesses adequate bioavailability. Compounded capsules from bulk powders may not be absorbed.
Distribution
Very high protein binding. Widely distributed to lipid-rich tissues (highly lipophilic). Skin, sebum, female reproductive tract, and pus have concentrations greater than serum. Minimal concentrations in CSF, urine, aqueous humor, and saliva.
Metabolism
Metabolized by the liver to many different metabolites, including the active metabolite hydroxyitraconazole.
Elimination
Elimination may be a saturable process. Because of its long half-life, steady-state plasma levels are not reached for at least 6 days without a loading dose.
Overdose
There is very limited information on acute toxicity.
- Decontamination: Giving oral antacids may help reduce absorption. If a large overdose occurs, consider gut emptying and provide supportive therapy.
- Clearance: Itraconazole is not removed by dialysis.
- Chronic Toxicity: In studies, dogs receiving 40 mg/kg PO daily for 3 months demonstrated no overt toxicity.
Available products
Formulations
- Capsules
- 100 mg capsule
- 10 mg/ml oral solution
Veterinary
- Intrafungol® (Janssen) oral liquid 10 mg/mL (Available in UK/select countries)
- Itrafungol 10 mg/ml oral solution
Human-labeled
- Sporanox® Capsules 100 mg (and generics)
- Sporanox® Oral Solution 10 mg/mL
- Sporanox 100 mg capsule
Regulatory status
POM-V
POM-V, POM
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Capsules should be stored between 15-25°C and protected from light and moisture. Oral solution should be stored at temperatures less than 26°C, and protected from freezing.
Client information
Important Administration Instructions:
- Capsules: Must be given with food to ensure proper absorption. For cats and small dogs, capsules can be opened and the pellets mixed with a small amount of tasty food (e.g., butter, cheese, canned diet).
- Liquid Solution: Should ideally be given on an empty stomach in mammals.
What to Watch For:
- Loss of appetite is often the very first sign that the medication is affecting the liver. Contact your veterinarian immediately if your pet stops eating, starts vomiting, or if you notice a yellowing of the eyes/gums (jaundice).
- In dogs, watch for unexplained skin sores or swelling of the legs.
Safety Warnings:
- Do not use compounded bulk powder versions of this drug. They are poorly absorbed and can lead to treatment failure, which is dangerous for serious fungal infections.
- Do not give with any other medications (especially antacids) without your veterinarian's approval.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.