Itraconazole

What is this medication for?

• Blastomycosis (often drug of choice unless severe hypoxemia present), histoplasmosis, dermatophytosis, Malassezia dermatitis, nasal aspergillosis
• Dermatophytosis (often first choice), cryptococcosis, blastomycosis

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

• Never substitute compounded bulk-powder capsules — documented poor/erratic absorption; use the commercial capsule or oral solution.
• Give capsules with food to maximize absorption (oral solution doesn't need food).

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Anorexia (Most common, often 2nd month of treatment)

Worth a phone call to your veterinarian

• Hepatotoxicity (↑ALT) (~10% at 10 mg/kg/day, ~5% at 5 mg/kg/day)
• Ulcerative skin lesions/vasculitis, limb edema (~7% at high dose)
• stomach/intestinal effects, liver damage, depression (Dose-related)
• Rare: erythema multiforme, toxic epidermal necrolysis (Rare, serious)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Azole hypersensitivity
• has or has had: Hepatic impairment, achlorhydria; reduced cardiac function (negative inotrope); African Grey parrots extremely sensitive

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • H2-blockers, PPIs, antacids
  • Cyclosporine, digoxin
  • Ivermectin
  • Cisapride
  • Benzodiazepines, corticosteroids, calcium channel blockers

Storage and handling

Practically insoluble in water; unstable outside manufacturer's original formulation. Do NOT use compounded capsules from bulk powder — poor/unreliable absorption.

Good to know

• Never substitute compounded bulk-powder capsules — documented poor/erratic absorption; use the commercial capsule or oral solution.
• Give capsules with food to maximize absorption (oral solution doesn't need food).
• Considered more effective and fewer endocrine side effects than ketoconazole, but significantly more expensive.