Levetiracetam

S-Etriacetam / Pyrrolidone-derivative

Also known as: Keppra XR · Desitrend · S-Etriacetam · UCB-22059 · UCBL059 · S-Etiracetam

Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference

20 mg/kg PO every 8 hoursPO· q8h

Body weight— 🐕

Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.

Dosing by species

🌎 NA — North America🌍 EU — Europe

Dogs

Indication	Dose	Route	Frequency	Duration	Region
As an add-on treatment for epilepsy in dogs refractory to phenobarbital and bromides	20 mg/kg PO every 8 hours	PO	q8h	—	🌎 NA
As an add-on treatment for epilepsy in dogs refractory to phenobarbital and/or bromides	7.1-23.8 mg/kg PO every 8 hours	PO	q8h	—	🌎 NA
Seizure management	10-20 mg/kg PO q8h	PO	q8h	—	🌎 NA
Seizure management	Initially, 20 mg/kg PO q8h. May increase dose in 20 mg/kg increments until efficacy achieved, side effects become apparent, or the drug becomes cost prohibitive.	PO	q8h	—	🌎 NA
Seizure management	20 mg/kg PO q8h; may also be given as an IV bolus (20 mg/kg).	PO/IV	q8h	—	🌎 NA
Single-dose pharmacokinetic study	60 mg/kg IV bolus dose	IV	Once	—	🌎 NA
For status epilepticus	Initially, lorazepam at 0.2 mg/kg IV once, followed by a bolus IV loading dose of levetiracetam at 60 mg/kg.	IV	Once	—	🌎 NA

Single-dose pharmacokinetic study: Well tolerated and achieves plasma drug concentrations within or above the therapeutic range reported for humans for at least 8 hours.

Cats

Indication	Dose	Route	Frequency	Duration	Region
As an add-on to phenobarbital treatment for epilepsy	Initially, 20 mg/kg PO three times daily; slowly increase to effect	PO	TID	—	🌎 NA
As an adjunct to phenobarbital in suspected idiopathic epilepsy	Initially, 20 mg/kg PO three times daily. Monitor as below. If ineffective, increase dose in 20 mg/kg increments.	PO	TID	—	🌎 NA

Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.

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Overview

Levetiracetam is a novel, structurally unique anticonvulsant used primarily as an adjunct therapy in veterinary medicine.

Dogs: Used as a third-line agent for refractory epilepsy or when phenobarbital or potassium bromide are contraindicated or poorly tolerated. Note that dogs may develop a 'honeymoon effect' where efficacy wanes over time.
Cats: Typically used as a second-line add-on when phenobarbital is insufficient, or as monotherapy if phenobarbital is not tolerated.

Clinical Pearl: Levetiracetam is highly favored for patients with hepatic impairment because it undergoes minimal hepatic metabolism and does not rely on the cytochrome P450 enzyme system. However, its short half-life necessitates frequent (TID) dosing, which can be challenging for pet owners.

Mechanism of action

The exact mechanism of levetiracetam's antiseizure activity is not fully elucidated, but it is distinct from traditional anticonvulsants (which typically affect GABA or ion channels).

Binds specifically to Synaptic Vesicle Protein 2A (SV2A) in the central nervous system.
Binding to SV2A → modulates neurotransmitter release into the synaptic cleft → selectively prevents hypersynchronization of epileptiform burst-firing and propagation of seizure activity.
It does not affect normal neuronal excitability.

Safety & warnings

Contraindications

Hypersensitivity to levetiracetam or any of its components
Severe renal disease

Adverse effects

Sedation (most common in dogs)
Lethargy (most common in cats)
Decreased appetite (most common in cats)
Behavior changes
Gastrointestinal effects
Sedation (dogs)
Ataxia (dogs)
Reduced appetite (cats)
Hypersalivation (cats)
Lethargy (cats)

Precautions

Renal Impairment: Clearance is primarily renal (glomerular filtration and active tubular secretion). Dosage amounts or intervals must be adjusted in patients with decreased creatinine clearance.

Pregnancy/Nursing: FDA Category C. High doses in animal models showed embryofetal mortality and minor skeletal abnormalities. Excreted in maternal milk; use with caution in nursing patients.
Withdrawal: Abrupt discontinuation may precipitate withdrawal seizures; taper slowly if discontinuing.

Drug interactions

NSAIDs (naproxen, ketorolac)

May increase the risk for seizures (reported in humans; veterinary significance unclear).

PhenobarbitalModerate

Significantly increases levetiracetam clearance and reduces its half-life in dogs (from 3.43 hrs to 1.73 hrs); dosage adjustments may be required.

Monitoring

Therapeutic drug monitoring (target range 5-45 mcg/mL) approximately one week after starting, then every 6-12 months (primarily to adjust dosage)
Seizure activity log (frequency, duration, severity)
Routine CBC and basic metabolic panel every 6 months
Adverse effects (sedation, lethargy, appetite changes)
Seizure frequency and severity
Renal function (BUN, Creatinine, SDMA) especially in older patients
Therapeutic drug monitoring is rarely required but can be performed

Pharmacokinetics

Half-life

Cats~3 hours (wide inter-patient variation)Dogs2-5 hours

Absorption

Well absorbed after oral dosing; peak levels occur in about 2 hours in dogs and cats. In humans, food delays the rate but not the extent of absorption.

Distribution

Volume of distribution is about 0.9 L/kg in dogs. Less than 10% bound to plasma proteins in humans.

Metabolism

Not extensively metabolized. The acetamide group is enzymatically hydrolyzed to an inactive carboxylic acid metabolite. Hepatic CYP P450 isoenzymes are not involved.

Elimination

Primarily excreted unchanged via renal mechanisms (glomerular filtration and active tubular secretion). Clearance is significantly reduced in renal impairment.

Overdose

Levetiracetam is a relatively safe agent.

Dogs: Doses of 1200 mg/kg/day (~20x therapeutic dose) caused only salivation and vomiting.
Humans: Doses of 6000 mg/kg caused drowsiness. Other reported effects include depressed consciousness, agitation, aggression, and respiratory depression.
Treatment: Basically supportive. The drug can be removed with hemodialysis. Contact an animal poison control center for significant overdoses.

Available products

Formulations

Oral Tablets (film-coated, scored)
Extended-Release Oral Tablets
Concentrate for Injection
Oral tablets: 250 mg, 500 mg, 750 mg, 1 g
Oral solution: 100 mg/ml (300 ml bottle)
Coated granules: 250 mg/sachet
Injectable solution: 100 mg/ml (5 ml vial)
Infusion solution: formulated with sodium chloride at 500 mg/100 ml, 1000 mg/100 ml, 1500 mg/100 ml

Human-labeled

Levetiracetam Oral Tablets (film-coated, scored): 250 mg, 500 mg, 750 mg & 1000 mg (Keppra, generic)
Levetiracetam Extended-Release Oral Tablets: 500 mg & 750 mg (Keppra XR)
Levetiracetam Oral Solution: 100 mg/mL (Keppra, generic)
Levetiracetam Concentrate for Injection: 100 mg/mL in 5 mL single-use vials (Keppra)
Desitrend
Keppra (250 mg, 500 mg, 750 mg, 1 g tablets; 100 mg/ml oral solution; 100 mg/ml IV solution)

Regulatory status

European Union✓ ApprovedPrescription onlyEMA

🐕 Dogs🐈 Cats

POM (Prescription Only Medicine)

United Kingdom✓ ApprovedPrescription onlyVMD