Itraconazole for Veterinary Use

Therapeutic Class: Triazole Antifungal

Species: Horses

May Be Prescribed For: Ulcerative keratomycosis.

Itraconazole is a triazole antifungal drug that is used to treat systemic fungal-infections of dogs, cats, and humans. It also is used topically to treat ulcerative keratomycosis of horses. Triazoles are a subgroup of the azole group of drugs. These drugs are fungistatic at the concentrations used systemically and fungicidal at the concentrations that may be achieved topically.

Itraconazole is effective against a filamentous fungi, dimorphic fungi and yeasts. The mechanism of action is through the disruption of the oxidative enzymes of the fungal organism.

Topical itraconazole has been shown to be effective to treat ulcerative keratomycosis. It is particularly effective against aspergillus, one of the more-common fungal pathogens. The ophthalmic preparation of itraconazole contains 1% itraconazole, 30% DMSO, and artificial tears. This formulation is necessary because itraconazole is relatively insoluble in water.

Therapy for ulcerative keratomycosis needs to be quite aggressive. Many clinicians recommend topical treatment every two hours. Some animals with particularly difficult cases of ulcerative keratomycosis also may be treated systemically with oral itraconazole or oral lufenuron.

Uveitis may increase after the first day of therapy because of inflammation due to fungal death.

DMSO may be topically irritating in some horses.

Corticosteroids generally are contraindicated in cases of ulcerative keratomycosis. No drug interactions per se were found.

No information regarding overdose was found in the literature. Itraconazole is one of the less toxic azole drugs.