Terbinafine for Dogs and Cats

Molly Price, DVM
By Molly Price, DVM on Dec. 13, 2023
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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 Terbinafine for Dogs and Cats?

Terbinafine is an antifungal medication prescribed by veterinarians for treatment of ringworm fungal skin infections (dermatophytosis) in dogs and cats and sometimes for internal (systemic) fungal infections such as blastomycosis, histoplasmosis, coccidioidomycosis, cryptococcus, and sporotrichosis.

Terbinafine for dogs and cats is used mostly as a solo medication but may be used in combination with other antifungal medications. Compared to other antifungal medications such as ketoconazole and itraconazole, terbinafine is not as effective for yeast infections in dogs, such as malassezia, aspergillus, and candida. Your veterinarian will determine if terbinafine or a combination of antifungal treatments is best for your pet, based on their circumstances and symptoms.

Terbinafine is FDA-approved for human use under the brand name Lamisil® and as generic terbinafine. Terbinafine is available as a prescription oral tablet, over-the-counter creams and sprays such as Lamisil®, and topical generic terbinafine.

Terbinafine is currently not FDA-approved as a veterinary medication. However, it is 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 isn’t described on the drug label.

In certain circumstances, your vet may recommend a compounded formulation of terbinafine. 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. You can learn more about compounded medications here.

Terbinafine Considerations for Dogs and Cats

Terbinafine should not be used in pets with certain medical conditions, such as liver disease and kidney disease, in breeding, pregnant, or nursing pets, or in pets who are hypersensitive to the medication.

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

Treatment with terbinafine requires monitoring and supervision by your veterinarian with follow-up visits and skin testing to assess how well the medication is working for your pet. Before and during your pet’s treatment, your vet may order blood tests to evaluate the effects of the medication on your pet’s liver and kidneys.

How Terbinafine Works in Dogs and Cats

Terbinafine is classified as an antifungal medication. It works by blocking the susceptible fungus from creating a vital part of its cell membrane, thereby resulting in the death of the fungal organism.

Terbinafine Directions for Dogs and Cats

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

Terbinafine is best absorbed if given on a full stomach. Giving it with food can also decrease the risk of digestive upset.

This medication should not be given to breeding, pregnant, and lactating pets.

Missed a Dose?

Speak with your veterinarian about what to do if you forget to give a dose of terbinafine. Generally, they may instruct you to give it when you remember, or if it is almost time for your pet’s next dose, to skip the missed dose and resume your normal dosing schedule. Do not give extra or double doses.

Terbinafine Possible Side Effects in Dogs and Cats

Terbinafine is generally well tolerated in most dogs and cats. Side effects of terbinafine may include:

  • Gastrointestinal upset (vomiting, low appetite, diarrhea)

  • Panting (dogs)

  • Elevated liver levels (rare)

  • Lethargy and facial itchiness (cats)

Human Side Effects

Terbinafine 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 this medication, immediately call your physician or the national Poison Control Center hotline at 800-222-1222.

Call Your Vet If:

  • 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 terbinafine

Terbinafine Overdose Information in Dogs and Cats

Signs of an overdose of terbinafine may include vomiting, diarrhea, and loss of appetite.

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

Pet Poison Helpline (855) 764-7661

ASPCA Animal Poison Control (888) 426-4435

Terbinafine Storage for Dogs and Cats

Always confirm storage requirements by reading the prescription label.

This medication should be stored at or below controlled room temperature of 68–77 F.

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

Keep out of reach of children and pets.

Terbinafine for Dogs and Cats FAQs

Is terbinafine used for ear infections in dogs and cats?

No, oral or topical terbinafine is not an effective treatment for ear infections in dogs and cats, but some combination steroid antibiotic ear solutions contain terbinafine as their antifungal ingredient.

What is terbinafine for dogs?

Terbinafine is a prescription oral antifungal medication prescribed by veterinarians for treatment of fungal skin infections (ringworm) and sometimes for internal (systemic) fungal infections.

How long does it take for terbinafine to work in dogs?

Terbinafine starts working right away, but it may take several doses for you to observe a gradual improvement in your pet’s symptoms. It is important to understand that a fungal infection of the skin and especially a systemic (internal) fungal infection requires a treatment time of weeks to months, sometimes longer-term, for certain types of serious infections. It may take at least several weeks for you to notice the full effects of terbinafine.

No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.

Featured Image: Dacharlie/iStock via Getty Images Plus


Olsen GL, Deitz KL, Flaherty HA, et al. Use of terbinafine in the treatment protocol of intestinal Cryptococcus neoformans in a dog. Journal of the American Animal Hospital Association. 2012;48(3):216-220.

Moriello KA. Treatment of dermatophytosis in dogs and cats: review of published studies. Veterinary Dermatology. 2004;15(2):99-107.

Moriello K, Coyner K, Trimmer A, et al. Treatment of shelter cats with oral terbinafine and concurrent lime sulphur rinses. Veterinary Dermatology. 2013;24(6):618-620, e149-50.


Molly Price, DVM


Molly Price, DVM


Dr. Molly Price has practiced small animal medicine for over 20 years and is a graduate of Texas A&M College of Veterinary Medicine. She...

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