By Lauren R. Forsythe, PharmD, MBA, DICVP; Rania Gollakner, BS, DVM, MPH

What is itraconazole?

Itraconazole (brand names: Itrafungol®, Sporanox®, Onmel®) is a systemic antifungal medication used to treat fungal infections such as ringworm and blastomycosis. Its use in dogs, small mammals, and some exotics to treat fungal infections is “off label” or “extra label”. Use of the human version of this drug is “off label” or “extra label” in cats and dogs. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is itraconazole given?

  • Itraconazole is given by mouth in the form of a capsule, tablet, or liquid solution.
  • The veterinary oral liquid may be given with or without food, but if vomiting occurs on an empty stomach, try giving it with a small meal or treat.
  • Capsules and tablets should be given with a high-fat meal.

This medication should not be compounded, as compounds prepared from bulk chemical are unlikely to be effective.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. If it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects?

Itraconazole may cause the following side effects:

  • gastrointestinal effects such as lack of appetite, vomiting, and weight loss
  • skin lesions that ulcerate (break open)
  • swelling of the extremities
  • a temporary increase in saliva production, when using the oral solution
  • liver toxicity and inflammation of the blood vessels (signs include yellowing of the eyes, skin, or gums; ongoing vomiting; severe or bloody diarrhea; painful abdomen; changes in behavior)

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This medication can take a few weeks before full effects are observed, but gradual improvements are usually noticeable after a few days.

This moderate-acting medication should stop working in a few days, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Itraconazole should NOT BE USED by pets that are allergic to it or similar antifungals.

It should be USED WITH EXTREME CAUTION in pets:

  • with liver disease
  • with low stomach acid production;

It should be USED WITH CAUTION in pets:

  • with heart disease
  • that are pregnant, breeding, or nursing, as its safety has not been established in these cases

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with itraconazole:

  • antacids
  • benzodiazepines
  • calcium channel blocking agents
  • ciprofloxacin
  • cisapride
  • corticosteroids
  • cyclosporine
  • fentanyl
  • H2 blockers
  • ivermectin
  • macrolide antibiotics
  • methadone
  • meloxicam
  • phenobarbital
  • proton-pump inhibitors
  • sildenafil
  • tricyclic antidepressants

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is there any monitoring that needs to be done with this medication?

  • When using itraconazole long-term, your veterinarian will monitor your pet’s liver values.
  • Your veterinarian will monitor your pet to be sure that the medication is working.
  • Monitor for any side effects and contact your veterinarian immediately if any side effects are observed.

How do I store itraconazole?

  • Capsules and tablets should be protected from light and kept in a dry place between 15°C and 25°C (59°F and 77°F).
  • Oral solution should be stored at room temperature between 20°C and 25°C (68°F and 77°F).

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

Related Articles