Itraconazole for Dogs: A Medication That Treats Fungal Infections Like Ringworm

Itraconazole (Sporanox) is an antifungal medication commonly prescribed to dogs to treat fungal infections such as ringworm. Itraconazole is a very effective antifungal and is considered safe for most dogs. Continue reading to learn more about itraconazole.

Itraconazole for dogs at a glance

What is itraconazole used for in dogs, and how does it work?

Itraconazole is used to treat fungal infections in dogs. It is a preferred choice to treat fungal infections that have spread all over a dog’s body, including: 

• Valley fever

• Ringworm

• Blastomycosis

Itraconazole is part of a class of antifungal medications called azoles. Azole antifungals are named for their chemical structure and are used to treat a wide range of fungal infections. Azole antifungals get rid of fungal infections by damaging the membrane of fungal cells. This results in the death of the cells. 

Use of itraconazole in dogs is considered to be “off-label” or “extra-label,” because the medication has not been approved by the FDA for veterinary use in dogs. As such, it is very important to follow dosage instructions from your veterinarian closely, as these may vary from what is written on the medication’s label.

How is itraconazole given for dogs and what is the standard dosage?

Itraconazole comes in 100 mg capsules. It’s also available in a liquid form. The correct dosage depends on the condition being treated, as well as a dog’s weight. However, the standard dosage of itraconazole for dogs ranges from 5 mg/kg of body weight to 10 mg/kg of body weight. 

Itraconazole can be given either once a day or split into two doses that are given 12 hours apart. The liquid form of itraconazole can be given with or without food. Itraconazole capsules should be given with a high-fat meal. 

It can take a few weeks for itraconazole to reach its full effects. But you should see some improvement after giving your dog the medication for a few days. 

To fully treat the infection, it is very important to give your dog the full course of itraconazole, as prescribed by your veterinarian. Continue giving your dog the medication even if you think they are feeling better.

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What are the common side effects of itraconazole in dogs?

In general, itraconazole is well tolerated by most dogs and has a low risk of side effects. The most common itraconazole side effect in dogs is loss of appetite. 

Occasionally, the medication can also cause: 

• Vomiting

• Diarrhea

• Drooling 

If your dog experiences vomiting or loss of appetite after taking itraconazole on an empty stomach, try giving them the medication with a small meal or treat. 

Any itraconazole side effects should resolve in a day or two after you stop giving your dog the medication. However, dogs with liver or kidney disease may take longer to clear the medication from their system.

What are the most serious risks of itraconazole for dogs?

Though rare, itraconazole can cause signs of liver damage in dogs. This may occur in up to 10% of dogs who take the medication. Signs of liver toxicity in dogs include:

• Jaundice (yellowing of the skin or eyes)

• Loss of appetite

• Vomiting

• Pain in the abdomen

Other rare but serious side effects associated with itraconazole for dogs include:

• Open sores or rash

• Swollen legs

• Vasculitis (inflammation of blood vessels) with symptoms including fever, bruising, and low energy

If your dog develops any of these symptoms while receiving itraconazole, stop giving them the medication. Then, call your veterinarian immediately. 

Itraconazole should be used with caution in dogs that have heart disease or liver disease. It should also be used with caution in dogs that are pregnant, breeding, or nursing.

Does itraconazole interact with any other dog medications?

Itraconazole for dogs is known to interact with a wide variety of medications. It should be used with caution in dogs that receive any of the following:

• Amphotericin B

• Antidepressant or anti-anxiety medications

• Benzodiazepines such as alprazolam (Xanax) 

• Bronchodilators such as theophylline and aminophylline

• Chemotherapy medications

• Cimetidine

• Cisapride

• Corticosteroids (steroids)

• Cyclophosphamide

• Cyclosporine

• Heart medications

• Pain medications, including NSAIDs and opioids 

• Rifampin

• Thiazide diuretics 

• Tramadol

• Warfarin

All azole antifungals, including itraconazole, can alter how many other medications are metabolized. So if your dog is prescribed itraconazole, make sure your veterinarian knows about any other medications and over-the-counter treatments your dog takes.

What should you do if your dog misses a dose of itraconazole?

If your dog takes itraconazole once a day and you forget to give them a dose, give them the medication as soon as you remember. Then, resume giving it to them at the regular time the next day.

If your dog gets itraconazole twice daily and it is close to the time for the next scheduled dose, skip the missed one. Then, give them the next dose at the regular time. Never give your dog a double dose to make up for a missed one. And always give them their doses at least 6 hours apart. 

Why trust our experts?

Written by:

Sarah J. Wooten, DVM, CVJ

Dr. Sarah Wooten, DVM, CVJ, is a well-known international influencer in the veterinary and animal healthcare spaces. She has 16 years of experience in private practice and more than 15 years experience in veterinary media work.

Edited by:

Renée Fabian, MA

Renée Fabian is the senior pet health editor at GoodRx. She’s worked for nearly 10 years as a journalist and editor across a wide range of health and well-being topics.

Reviewed by:

Ghanasyam Bey, DVM

Ghanasyam Bey, DVM, is from Cleveland, Ohio, and attended Princeton University for undergraduate studies. After a year of biology research at Duke University, he attended Ohio State College of Veterinary Medicine.

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