Ketoconazole: A Versatile Treatment Option for Fungal Infections in Dogs

Ketoconazole is a prescription antifungal medication that has been used to treat a variety of fungal infections in dogs. This medication is available in different formulations, making it a versatile treatment option for dogs with fungal infections.

## What Does Ketoconazole Treat?

Ketoconazole is used to treat a range of fungal and yeast infections in dogs. Some of the fungal organisms that it may be used for include Aspergillus, Blastomyces, Candida, Coccidioides, Cryptococcus, Histoplasma, Malassezia pachydermatis, Microsporum, Sporotrichosis, and Trichophyton.

For localized infections, a topical formulation of ketoconazole may be prescribed by a veterinarian. This can be applied directly to the infection site, such as an ointment for yeasty ears or a spray for affected skin on the belly.

Oral tablets are generally reserved for systemic infections that impact the lungs, bones, or deep tissues such as the nail beds. Oral ketoconazole may also be prescribed if a dog has a severe or stubborn local infection that has resisted topical treatment.

## How Does Ketoconazole Work?

Ketoconazole works by damaging the fungi's cell walls and stopping it from multiplying. This kills the fungal organism and clears the infection. The length of time it takes to see improvement can vary depending on the severity of the infection, with minor infections showing improvement within days and more severe infections taking two weeks or longer.

In addition to battling fungi, ketoconazole has two other less common uses in dogs. It may be used to help treat Cushing's syndrome by hindering the production of steroids in the body. It also may be given to dogs taking the immunosuppressant cyclosporine because it slows the metabolism of this drug, enabling the dog to take lower doses.

### How Long Will My Dog Need Ketoconazole?

The length of treatment with ketoconazole depends on the type and location of the infection. Minor ear and skin infections are often treated for a week or two, while more robust infections may require several weeks of treatment. Severe systemic infections such as Valley Fever and blastomycosis often require a month or more of treatment, and some dogs may need to take ketoconazole for the rest of their lives.

## Ketoconazole Shampoo for Dogs

Ketoconazole shampoo is a great option for dogs with fungal skin infections. However, what is available over the counter is not prescription strength. It is essential to follow all instructions on the label closely, as most medicated shampoos work best when allowed to soak on the dog for several minutes before being rinsed off.

Expect to bathe your dog multiple times a week for two to four weeks. For localized infections, you may only need to bathe the affected area.

## Ketoconazole Side Effects

Veterinarians like to use topical formulations of ketoconazole when possible to minimize the risk of side effects. By applying the drug directly to the affected skin, other parts of the body are not exposed and lower doses are needed. It is essential not to allow your dog to lick ketoconazole sprays, ointments, or shampoos.

Oral ketoconazole should be given with food to minimize the risk of stomach upset. Potential side effects from ketoconazole include nausea, vomiting, diarrhea, poor appetite, weight loss, elevated liver values, lethargy, liver damage, incoordination, and transient changes in hair color. Side effects are more likely if your dog takes high doses of ketoconazole or if she needs to take it for a prolonged period.

If your dog must be on ketoconazole long-term, your veterinarian will recommend bloodwork every three to six months to monitor her liver values. If your dog shows any signs of illness, contact your veterinarian to ask for next steps. In some cases, your dog's dosage may be adjusted, or she might be switched to a different treatment option.