Fluconazole is an antifungal medication that veterinarians commonly prescribe off-label to treat certain fungal infections in cats and dogs. This medication comes in tablet and liquid suspension forms that pets take by mouth. The injectable form of the antifungal is only used in veterinary clinics. Side effects of fluconazole in cats and dogs can include vomiting, diarrhea, and poor appetite.
Fluconazole is an azole antifungal. It works by destroying the protective outer covering of the fungus that’s causing the infection. The fungus can’t survive when its outer covering gets damaged.
The following side effects might get better over time as your pet gets used to the medication. Let your veterinarian know immediately if your pet continues to experience these symptoms or if they worsen over time.
For dogs:
Contact your veterinarian immediately if your pet experiences any of the following.
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Rare
Chills
clay-colored stools
dark urine
difficulty with swallowing
dizziness
fast heartbeat
general feeling of tiredness or weakness
headache
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
light-colored stools
loss of appetite
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
stomach pain, continuing
tightness in the chest
unpleasant breath odor
unusual tiredness or weakness
upper right abdominal or stomach pain
vomiting
vomiting of blood
yellow eyes and skin
Incidence not known
Black, tarry stools
blistering, peeling, or loosening of the skin
chest pain or discomfort
decreased urine
fainting
hoarseness
increased thirst
irregular or slow heart rate
joint or muscle pain
loss of bladder control
lower back or side pain
mood changes
muscle pain or cramps
muscle spasm or jerking of the arms and legs
numbness or tingling in the hands, feet, or lips
painful or difficult urination
pale skin
red skin lesions, often with a purple center
red, irritated eyes
seizures
sores, ulcers, or white spots in the mouth or on the lips
sudden loss of consciousness
swollen glands
unusual bleeding or bruising
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Fearfulness, suspiciousness, or other mental changes
seeing, hearing, or feeling things that are not there
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Belching
change in taste or bad, unusual, or unpleasant (after) taste
indigestion
stomach discomfort or upset
Incidence not known
Hair loss or thinning of the hair
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Tips for the liquid suspension form of fluconazole:
It depends whether fluconazole is appropriate and necessary to treat your dog’s ear infection. If your pet has a fungal ear infection, it’s possible that your vet might prescribe fluconazole. Typically, medications like fluconazole are used when the ear infection doesn’t improve with topical medications first. Keep in mind that antifungal medications like fluconazole won’t treat and heal ear infections that are caused by bacteria or viruses; your dog will need other treatment for these types of ear infections. Talk to your vet about treatment options for your dog’s ear infection and how to prevent future ear infections.
It depends. Your veterinarian will tell you how long to give your dog fluconazole based on what type of fungal infection your pet has and how severe it is. Some infections need only a few days of medication to treat them, while others require weeks or months. You should follow your veterinarian’s directions and make sure your dog completes the entire prescribed course of medication.
Most dogs can take fluconazole safely, although no medication is 100% safe. Common side effects for dogs are vomiting, low appetite, and diarrhea. But liver damage can be a rare but serious side effect of fluconazole, so the medication should be used cautiously in dogs with liver problems. You should also use fluconazole cautiously in dogs with kidney problems because they can’t get rid of the medication from their body as well. This can cause the medication to stay in the body longer and build up. When dogs have too much fluconazole in their body, they’re at higher risk for serious side effects of the medication. Talk with your vet if you’re concerned about whether fluconazole is safe for your dog.
In general, fluconazole is safe for most cats, although there's a possibility for mild side effects like vomiting, diarrhea, and poor appetite. But the medication can sometimes cause more serious side effects like liver irritation. For this reason, it should be used cautiously in cats with liver problems because of the risk that the liver damage might get worse. In addition, you should use fluconazole cautiously in cats with kidney problems. When the kidneys don’t work as well, fluconazole can stay in the body longer and build up. This can make them more likely to have serious side effects from the medication. Speak with your vet if you have concerns about whether fluconazole is safe for your cat.
Fluconazole is a medication that’s FDA approved for people, but it’s also commonly prescribed off-label by vets for treating certain fungal infections in dogs. This is because there aren't any commercially available forms of fluconazole that are specifically approved for dogs. Follow your vet’s directions to give the right amount of this medication to your pet. Don’t rely on dosing information for people because it could be too big of a dose for your dog. Your vet might recommend you to give your dog more than 1 tablet per dose, prescribe the liquid form of the antifungal, or have the medication compounded so your dog gets the dose they need. Ask your vet if you have any questions about giving fluconazole to your dog.
It depends on what other medications your pet is taking. Fluconazole can interact with many medications like cyclosporine and certain pain medications called nonsteroidal anti-inflammatory drugs (NSAIDs). Interactions that fluconazole can have with other medications can raise the risk of side effects from both medications. Taking interacting medications could also cause fluconazole to not work as well, which could make their fungal infection last longer. Tell your veterinarian and pharmacist about all your pet's medications, supplements, and herbal remedies so they can decide if these medications are safe for your pet to take together.
Fluconazole could treat ringworm in cats and in dogs. But it’s typically not the first-choice treatment option because there are other antifungals that work better to get rid of the fungal infection. Most times, vets will treat ringworm with other oral antifungals like itraconazole for your cat or for your dog along with a topical medication (like chlorhexidine/miconazole) that’s applied directly onto the affected area(s). Speak with your vet about the best option to treat your pet’s ringworm.
Fluconazole can cause some serious health issues. This risk might be even higher for certain pets. If this worries you, talk to your veterinarian about other options.
Liver damage can happen in cats and in dogs that take fluconazole. In a study that specifically looked at how fluconazole affects liver function in dogs, some dogs had higher-than-normal liver enzyme levels on their blood test results. Having elevated liver enzyme levels can mean that the liver is irritated. Liver enzyme levels generally go back to normal after the vet lowers the fluconazole dose or after your pet stops taking the medication.
Signs of liver damage to watch out for in cats and dogs include yellowing of their eyes or skin, swelling around the stomach, vomiting, diarrhea, and low appetite or energy. If you notice signs of liver damage in your pet, contact your veterinarian, an emergency veterinarian, or a pet poison hotline immediately.
Fluconazole comes in tablets and a liquid suspension. It can sometimes be made or compounded into a form that fits your pet's needs.
Most times, dosing is based on your pet’s weight. The vet will determine the length of therapy based on the type of fungal infection and your pet’s response to fluconazole.
Cats: The dose is usually rounded to 50 mg by mouth every 12 or 24 hours. Your vet might use a different dose for your cat depending on what type of infection it is and how serious it is.
Dogs: The typical dose ranges 5 mg/kg to 10 mg/kg by mouth every 12 or 24 hours.
Fluconazole also comes in an injectable form that’s given through your pet’s vein (IV) by a veterinarian or technician.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.