levetiracetam ER
Extended-release levetiracetam (Keppra XR) is an antiepileptic medication that’s used to manage seizures for dogs and for cats. It’s an extended-release (ER) tablet that pets take by mouth. Levetiracetam ER is available at regular pharmacies with a prescription from the vet. Pets usually need to take their dose twice per day. Side effects of levetiracetam ER aren’t too common but can include sleepiness and trouble walking.
What is Levetiracetam ER for pets?
What is Levetiracetam ER for pets used for?
How Levetiracetam ER for pets works
Levetiracetam ER is an antiepileptic medication, which means it helps with seizures.
It’s not clear how levetiracetam ER works to lessen how often seizures happen. But it’s thought to work by blocking certain chemicals in the brain to calm down brain activity. This helps prevent seizures.
Drug Facts
More on Levetiracetam ER essentials
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What are the side effects of Levetiracetam ER for pets?
Common Side Effects
- Sleepiness
- Trouble walking
Other Side Effects
- Low energy
- Low appetite
- Vomiting
- Drooling
- Changes in behavior
Serious Side Effects
- Withdrawal seizures
The following side effects have also been reported
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:
More common
Aggressive or angry
change in personality
chills
crying
deep or fast breathing with dizziness
delusions of persecution, mistrust, suspiciousness, or combativeness
false or unusual sense of well-being
feeling of unreality
general feeling of discomfort or illness
headache
hoarseness
irregular heartbeat
irritability
joint pain
loss of appetite
lower back or side pain
mental depression
muscle aches and pains
numbness of the feet, hands, and around the mouth
painful or difficult urination
quick to react or overreact emotionally
rapidly changing moods
restlessness
sense of detachment from self or body
shaking
shivering
sleepiness or unusual drowsiness
stuffy or runny nose
sweating
trouble sleeping
unusual tiredness or weakness
vomiting
Less common
Bloody nose
burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
clumsiness or unsteadiness
discouragement
dizziness or lightheadedness
double vision
feeling of constant movement of self or surroundings
feeling sad or empty
increase in body movements
loss of bladder control
loss of memory
mood or mental changes
outburst of anger
pain or tenderness around the eyes and cheekbones
problems with memory
redness or swelling in the ear
seizures
sensation of spinning
shakiness and unsteady walk
shakiness in the legs, arms, hands, or feet
tightness of the chest
trembling or shaking of the hands or feet
trouble concentrating
unsteadiness, trembling, or other problems with muscle control or coordination
Incidence not known
Attempts at killing oneself
being forgetful
bleeding gums
blistering, peeling, or loosening of the skin
blood in the urine or stools
bloody, black, or tarry stools
blurred vision
changes in vision
coma
confusion
dark urine
difficulty with moving
fast heartbeat
fever with or without chills
general feeling of tiredness or weakness
high fever
increased thirst
indigestion
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
light-colored stools
muscle pains or stiffness
pains in the stomach, side, or abdomen, possibly radiating to the back
pale skin
pinpoint red spots on the skin
red skin lesions, often with a purple center
red, irritated eyes
skin rash, encrusted, scaly, and oozing
sores, ulcers, or white spots on the lips or in the mouth
stomach pain, continuing
swelling of the face, ankles, or hands
swollen glands
swollen joints
thoughts or attempts at killing oneself
trouble with balance
twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
uncontrolled jerking or twisting movements of the hands, arms, or legs
uncontrolled movements of the lips, tongue, or cheeks
unexplained bleeding or bruising
unusual bleeding or bruising
upper right abdominal or stomach pain
yellow eyes or skin
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:
More common
Loss of strength or energy
muscle pain or weakness
tender, swollen glands in the neck
trouble swallowing
unusual weak feeling
voice changes
Less common
Body aches or pain
burning, dry, or itching eyes
change in the color of the skin
congestion
cough increased
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.
Pros and cons of Levetiracetam ER for pets
Pros
Given fewer times per day than immediate-release tablets
Low risk of serious side effects
No need for regular blood tests to check medication levels and safety if given by itself
Pharmacist tips for Levetiracetam ER for pets
Don’t suddenly stop giving your dog or cat levetiracetam ER. Otherwise, it can make the seizures come back and possibly be even worse. Make sure you always have enough levetiracetam ER for your pet so you don’t run out. Talk to your veterinarian first if you want your pet to stop taking this medication. They can give you instructions to do it safely.
You can give levetiracetam ER with or without food. If your pet vomits or doesn’t feel well after taking it on an empty stomach, try giving the medication with a little bit of food next time.
Your pet must swallow levetiracetam ER whole. Try putting the tablet deep in your pet’s mouth, near the back of their throat. Then, gently close their mouth, hold it shut, and rub their throat or blow on their nose to help them swallow. You can also use a pet piller if you don’t want to reach into your pet’s mouth. Ask your vet for more tips.
Don’t cut or crush levetiracetam ER or let your pet chew the tablet. It can cause too much medication to get released into your pet’s body too fast and lead to side effects. Talk to your vet if it’s hard to get your pet to swallow the tablet whole.
You might find the shell of the levetiracetam ER tablet in your pet’s stool. This is called a “ghost tablet.” Your pet most likely got the whole dose of the medication after they swallowed the tablet. But the shell of the tablet can pass through the entire body and out into the stool looking unchanged. Talk to your veterinarian if you’re concerned that your pet didn’t get all of the medication in the tablet.
Levetiracetam ER has a “honeymoon” effect. This means that the medication works well at first, usually for about several months. But then, it might not work as well to control seizures at the same dose later on as your pet gets used to the medication. To help keep seizures under control, the vet might need to give your pet a higher dose as treatment goes on.
Some pets need to take phenobarbital and levetiracetam ER together to control seizures. If this is the case, your vet might adjust your pet’s levetiracetam ER dose. This is because phenobarbital can lower the levels of levetiracetam ER in the body, which can make it not work as well.
Tell your veterinarian right away if your pet gets pregnant. It isn’t known if levetiracetam ER is safe for pregnant dogs or cats. But studies do show that it can harm babies of other animal species when it’s given during pregnancy. Your vet will see if the benefits outweigh the risks of using this medication for your pet.
Also talk to your vet if your pet is nursing. They can discuss whether it’s safe for your pet to nurse while they’re taking levetiracetam ER.
Frequently asked questions about Levetiracetam ER for pets
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What are the risks and warnings for Levetiracetam ER for pets?
Levetiracetam ER 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.
Withdrawal seizures
Risk factors: Stopping levetiracetam ER suddenly
Talk to your vet before lowering your pet’s dose or stopping giving them levetiracetam ER. If you do this suddenly, your pet can be at risk of having seizures again. These withdrawal seizures might happen more often or be less controllable.
To lower the risk of withdrawal seizures, the vet will slowly lower the dose over time to see how your pet reacts. Make sure you know when you need to get refills so your pet doesn’t run out of medication.
Possible changes in behavior
Risk factors: Previous behavior problems
Although uncommon, your dog or cat might behave differently while they’re taking levetiracetam ER.
In one study, some dogs that took immediate-release levetiracetam showed signs of anxiety, aggression, or depression. Others wandered around aimlessly or had more attention-seeking behavior. Some dogs that already had behavior problems also got worse. But other dogs in the same study were calmer or happier. In another study, some cats became more alert and had more energy after taking the medication.
Talk to your vet if you’re worried about any unusual behavior your pet shows after starting levetiracetam ER.
Risk of having more side effects for pets with kidney problems
In a study, dogs with kidney problems had more side effects after taking immediate-release levetiracetam. These included being sleepy, having trouble walking, and having an upset stomach. Their blood tests also showed higher levels of creatinine and blood urea nitrogen (BUN). These test results might mean the medication made their kidney problems worse.
Let your vet know if your pet has kidney problems. Your vet might need to prescribe a lower dose of levetiracetam ER to be safe. Also, watch how much water your pet is drinking and be sure they’re staying hydrated. This medication can make pets feel sleepy, which might make them drink less water. Dehydration can lead to kidney problems or make them worse.
Levetiracetam ER dosage forms
Typical dosing for Levetiracetam ER for pets
Interactions between Levetiracetam ER and other drugs for pets
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.
- Calcifediol
- Methotrexate
- Orlistat
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.
- Carbamazepine
- Ginkgo
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References
Best studies we foundAkin, E. Y. (2020). Treatment plans for routine and refractory canine epilepsy. Today’s Veterinary Practice.
Barnes Heller, H., et al. (2018). Serum levetiracetam concentrations and adverse events after multiple dose extended release levetiracetam administration to healthy cats. Journal of Veterinary Internal Medicine.
Boozer, L. B., et al. (2015). Pharmacokinetic evaluation of immediate- and extended-release formulations of levetiracetam in dogs. American Journal of Veterinary Research.
Britain Small Animal Veterinary Association. (2020). Levetiracetam.
Castel, A. (2025). Anticonvulsants for treatment of animals. Merck Manual Veterinary Manual.
Charalambous, M., et al. (2018). Systematic review of antiepileptic drugs' safety and effectiveness in feline epilepsy. BioMed Central Veterinary Research.
Erath, J. R., et al. (2020). Behavioral changes under levetiracetam treatment in dogs. Frontiers in Veterinary Science.
Gesell, F. K., et al. (2015). Antiepileptic drug withdrawal in dogs with epilepsy. Frontiers in Veterinary Science.
Gim, S. Y., et al. (2021). Use of levetiracetam in epileptic dogs with chronic kidney disease: A retrospective study. Veterinary Sciences.
Hazenfratz, M., et al. (2018). Recurrent seizures in cats: Treatment – which antiepileptic drugs are recommended? Journal of Feline Medicine and Surgery.
Lowrie, M., et al. (2017). Levetiracetam in the management of feline audiogenic reflex seizures: a randomised, controlled, open-label study. Journal of Feline Medicine and Surgery.
Moore, S. A., et al. (2010). Levetiracetam pharmacokinetics in healthy dogs following oral administration of single and multiple doses. American Journal of Veterinary Research.
Plumb’s Veterinary Medication Guides. (n.d.). Levetiracetam.
Podell, M., et al. (2016). 2015 ACVIM small animal consensus statement on seizure management in dogs. Journal of Veterinary Internal Medicine.
Sun, D., et al. (2016). Ghost-pill-buster: A case study of intact levetiracetam extended-release tablets after dissolution testing. CNS Drugs.
Van Vertloo, L. (2025). Renal dysfunction in dogs and cats. Merck Manual Veterinary Manual.
Westminster Pharmaceuticals, LLC. (2024). Levetiracetam ER- levetiracetam tablet, film coated, extended release [package insert]. DailyMed.
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