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 both 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 very carefully as their directions may be significantly different from those on the label.


How is itraconazole given?

Itraconazole is either 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 can take a few weeks before full effects are observed, but gradual improvements are usually noticeable after a few days.


What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.


Are there any potential side effects?

The most common side effect observed with itraconazole use is lack of appetite. Other significant side effects include skin lesions that ulcerate (break open) and swelling of the extremities. Liver toxicity and inflammation of the blood vessels may also occur. Signs of liver toxicity include yellowing of the eyes, skin, or gums, vomiting (that continues), severe or bloody diarrhea, painful abdomen (stomach), or changes in behavior. In cats, gastrointestinal effects such as lack of appetite, vomiting, and weight loss, as well as liver toxicity can occur. When using the oral solution, a temporary increase in saliva production occurs occasionally.

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 or with low stomach acid production and used carefully in pets with heart disease. Itraconazole should be used with caution in pets 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: amphotericin B, antacids, benzodiazepines, buspirone, busulfan, calcium channel blocking agents, ciprofloxacin, cisapride, colchicine, corticosteroids, cyclophosphamide, cyclosporine, digoxin, disopyramide, doxorubicin, ergot alkaloids, fentanyl/alfentanil, H2 blockers, ivermectin, macrolide antibiotics, methadone, meloxicam, midazolam, phenobarbital/phenytoin, proton-pump inhibitors, quinidine, rifampin, sildenafil, statins, sulfonylurea antidiabetic agents, tricyclic antidepressants, vincristine, warfarin.

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


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). The veterinary oral solution should be stored at room temperature between 20°C and 25°C (68°F and 77°F) and the human oral solution should be stored below 25°C and above freezing.


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.

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