Ketoconazole for Dogs

PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Is Ketoconazole Used for in Dogs?

Ketoconazole is a prescription antifungal medication used to help treat fungal infections such as yeast infections and ringworm in dogs.

Because cats are more prone to severe side effects such as liver toxicity with ketoconazole, vets will usually recommend other antifungal medications, such as itraconazole or fluconazole, before recommending ketoconazole.

Ketoconazole may also be prescribed to treat hyperadrenocorticism (Cushing’s disease) in dogs, but newer medications such as Vetoryl® (trilostane) can be more effective in treating the condition.

Ketoconazole comes in both brand name and generic oral tablet formulations as well as in topical products (sprays, shampoos, wipes, ear flush, ointment). It’s also available as a compounded formulation.

While ketoconazole is FDA-approved for human use, it is currently not FDA-approved as a stand-alone veterinary medication. It is, however, readily utilized in the veterinary field, and veterinarians can legally prescribe certain human drugs in animals in certain circumstances. This is called extra-label or off-label use because this use is not described on the drug label.

Common brand names of ketoconazole include Nizoral® and Ketochlor®.

In certain circumstances, your vet may recommend a compounded formulation of ketoconazole.

Compounded medications are prescribed if there’s a specific reason your pet’s health can’t be managed by an FDA-approved drug, such as if your pet has trouble taking pills in capsule form, the dosage strength is not commercially available, or the pet is allergic to an ingredient in the FDA-approved medication.

Compounded medications are not FDA-approved. They are created by either a veterinarian or a licensed pharmacist on an individual basis to best suit a patient’s particular needs.

How Ketoconazole Works in Dogs

Ketoconazole works by blocking a fungal organism from making part of their cell wall, thereby preventing the fungus from growing and multiplying.

Ketoconazole also works in the cells of mammals to mildly block the production of steroids such as cortisol in the body, which is why it has been used to treat canine Cushing’s disease.

Ketoconazole has the unique ability to slow down the metabolism (the body's breaking down) of cyclosporine, an immunosuppressive medication used for inflammatory and autoimmune conditions. If a pet needs to take cyclosporine long term, sometimes ketoconazole will be prescribed as well—not for treatment of a fungal infection, but to help reduce the pet's cyclosporine dosage and the cost of treatment.

Ketoconazole Directions for Dogs

Follow the directions on the drug label or as provided by your veterinarian.

Ketoconazole is best given with food, especially food higher in fat, as it can help with gastrointestinal side effects.

Ketoconazole should not be used in pets with certain medical conditions, such as liver disease, so speak with your vet to ensure this medication is right for your pet.

Giving ketoconazole with certain medications can result in health risks to your pet, so it’s important to discuss your pet’s medications, including vitamins and supplements, and medical conditions with your veterinarian.

Missed a Dose?

Speak with your veterinarian about what to do if you forget to give a dose of ketoconazole.

Generally, your vet may instruct you to give it when you remember, or, if it’s almost time for your next dose, to skip the missed dose and resume your normal dosing schedule.

Do not give extra or double doses.

Possible Side Effects of Ketoconazole in Dogs

Side effects are possible with this medication in dogs.

Side effects of ketoconazole in dogs may include:

• Vomiting

• Diarrhea

• Loss of appetite

• Weight loss

• Liver irritation

• Incoordination (poor balance)

• A temporarily lighter haircoat color that resolves on its own

Symptoms of liver irritation may include:

• Vomiting

• Loss of interest in food

• Yellow gums, skin, or whites of the eyes

• Lethargy

Some pets are more sensitive to this medication than others and are therefore more prone to experiencing side effects.

If you believe your pet may be experiencing any side effects of ketoconazole, consult your veterinarian.

Human Side Effects

Ketoconazole is also a prescription medication for humans, frequently with dosages different from those prescribed for your pet by a veterinarian. Due to possible side effects, humans should never use medicine dispensed for their pets and pets should not be given any medicine dispensed for a human’s use.

If you accidentally ingest ketoconazole prescribed to your pet, call your physician or the national Poison Control Center hotline at 1-800-222-1222.

Monitoring Your Pet

Specific monitoring or routine testing while your pet is on this medication may be recommended by your veterinarian depending on your pet’s individual needs, other medications they may be on, and/or the issue that initially caused your pet to be placed on this medication.

When To Call Your Vet

Call your veterinarian if any of the following apply:

• Severe side effects are seen (see above)

• Your pet’s condition worsens or does not improve with treatment

• You see or suspect an overdose

• You have additional questions or concerns about the use of ketoconazole

Ketoconazole Overdose in Dogs Information

Ketoconazole overdoses are rare, but signs of an overdose include:

• Vomiting

• Diarrhea

• Loss of appetite

• Liver irritation

If you suspect an overdose, immediately contact your veterinarian, seek emergency veterinary care, or contact an animal poison control center. Consultation fees often apply.

• Pet Poison Helpline® 855-764-7661

• ASPCA® Animal Poison Control 888-426-4435

How To Store Ketoconazole for Dogs

Follow these tips when storing your pet’s ketoconazole:

• Ketoconazole should be stored at controlled room temperatures between 68–77 degrees F (20–25 degrees C).

• Keep the container tightly closed to protect from moisture and light.

• Always confirm storage temperatures by reading the label.

• Compounded medications should be stored according to the compounding pharmacy’s label.

• Keep out of reach of children and pets.