Levetiracetam: veterinary dose and monograph

At a glance

Drug class

Veterinary drug

Also known as

Keppra, Keppra XR

Species with doses

Dogs, Cats and Horses

General dose range

20–60 mg/kg PO q8h — check the species tables for the indication

Routes

PO, IV, Rectal

Last reviewed

1 October 2026

Indications

• Idiopathic epilepsy (first-line or add-on)
• Refractory epilepsy (add-on to phenobarbital / KBr)
• Status epilepticus (IV bolus alternative to phenobarbital)
• Pulse therapy for cluster seizures ("LevoLoad" 60 mg/kg single dose at cluster onset)
• Hepatic disease patients where phenobarbital is contraindicated
• Geriatric epilepsy (better-tolerated than phenobarbital in older patients)

Levetiracetam dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Maintenance AED (monotherapy or adjunct): Papich 5e and Plumb’s p.723: 20 mg/kg PO q8h. Plumb’s (Dewey 2005): increase in 20 mg/kg increments until efficacy, adverse effects or cost limit. Dogs on phenobarbital clear levetiracetam faster and may need higher or more frequent doses.
• Status epilepticus / cluster seizures (IV): Papich 5e: 20 mg/kg IV bolus, repeated if necessary up to 60 mg/kg. Plumb’s p.723: 60 mg/kg IV bolus was well tolerated in normal dogs (Dewey 2008); status epilepticus — lorazepam 0.2 mg/kg IV then levetiracetam 60 mg/kg IV (Podell 2009). Continue oral maintenance afterwards.
• Maintenance — extended-release tablets: Papich 5e: XR tablets 30 mg/kg PO q12h. Do not split or crush XR tablets.
• Cluster seizures — rectal (no IV access): Papich 5e: 40 mg/kg per rectum using the 100 mg/mL solution produced effective concentrations; in many dogs the volume is too large to be practical.

Cats

• Maintenance AED: Papich 5e: 20 mg/kg PO q8h. Plumb’s p.723 (Pearce 2006; Bailey & Dewey 2009): start 20 mg/kg PO three times daily as an add-on to phenobarbital; increase in 20 mg/kg increments if ineffective. Bitter — compounded flavoured liquid helps.
• Maintenance — extended-release tablet: Papich 5e: 500 mg XR tablet per cat once daily (≈94 mg/kg). Do not split tablets.

Horses

• Seizures — short-term IV: Papich 5e: horses 30 mg/kg IV for short-term treatment. Plumb’s 10e gives no IV horse dose, and neither reference gives a foal-specific dose.
• Seizures — oral maintenance (Papich 5e, q24h): Papich 5e: horses 30 mg/kg q24h PO. REFERENCE CONFLICT on interval: Plumb’s 10e p.748 gives the same 30 mg/kg but every 12 hours (next row).
• Seizures — oral maintenance (Plumb’s 10e, q12h): Plumb’s 10e p.748 (extra-label): anticonvulsant, based on pharmacokinetic studies and presumed therapeutic levels — 30 mg/kg PO every 12 hours using immediate-release tablets. Crushed extended-release tablets gave similar serum concentrations but may be cost-prohibitive.

Contraindications

Hypersensitivity. Severe renal impairment: reduce dose (renally excreted unchanged — 66% of dose). Caution in pregnancy due to limited data. No food-animal use approved.

Species-specific warnings

Dogs: First-line option for hepatic disease, geriatric, and owner-preference cases. q8h dosing essential (short half-life ~3 h). XR for q12h convenience.

Cats: First-line AED for cats — phenobarbital is acceptable but more hepatotoxic; KBr is contraindicated in cats. Bitter — compound.

Horses: Foal seizures: 30 mg/kg IV load then 10–20 mg/kg q8h. Adult horse use is extra-label and rare.

Adverse effects

• Sedation, ataxia (mild, transient — usually resolves in 1–2 weeks)
• Hyporexia, vomiting (uncommon)
• Behavioural changes (rare — agitation, aggression)
• Thrombocytopenia (rare)
• NO hepatotoxicity (major advantage over phenobarbital)
• NO PU/PD/polyphagia (advantage over phenobarbital / KBr)

Drug interactions

• Phenobarbital, KBr: synergistic — common combination in refractory epilepsy
• No clinically significant CYP interactions (no hepatic metabolism)
• No interactions with: opioids, NSAIDs, anaesthetics, antibiotics
• CNS depressants: additive sedation only

Pregnancy and lactation

Limited vet data. FDA Category C (human). Crosses placenta. In epileptic dams, continue therapy as seizures pose greater risk than the drug.

Monitoring

• Seizure log — frequency, duration, post-ictal
• No mandatory serum drug monitoring (unlike phenobarbital) — clinical response is the endpoint
• Optional serum trough (4–37 µg/mL target) for refractory cases
• Renal function in advanced CKD — dose reduction if BUN/Cr elevated
• CBC every 6 months — rare thrombocytopenia
• No hepatic monitoring needed (no hepatic metabolism)

Toxicity and overdose

Extremely wide therapeutic margin. Overdose: sedation, ataxia, occasional vomiting — usually self-limiting. No hepatotoxicity, no cardiotoxicity, no nephrotoxicity at therapeutic doses. Reduce dose in advanced CKD (renally excreted).

Management: Supportive only — overdose well tolerated. Activated charcoal if recent ingestion. IV fluids. Monitor for sedation. Hemodialysis effective in severe overdose.

Clinical pearls

• First-line for: hepatic disease patients, geriatric patients, owners refusing phenobarbital, cats (no KBr available)
• Adjunct to phenobarbital in refractory epilepsy — start at 20 mg/kg PO q8h, titrate to 30–40 mg/kg q8h
• Status epilepticus IV: 30–60 mg/kg IV over 5 min — safer than phenobarbital IV (no respiratory depression)
• Pulse therapy "LevoLoad": 60 mg/kg single dose at first sign of cluster seizures
• XR formulation (Keppra XR) allows q12h dosing in dogs >20 kg — improves compliance
• NO need for serum monitoring routinely — major workflow advantage
• NO hepatic interactions — safe with cyclosporine, phenobarbital, opioids, NSAIDs simultaneously
• Bitter taste in cats — compound to flavoured liquid or use crushed in food

Mechanism of action

Pyrrolidone anticonvulsant. Binds the synaptic vesicle protein SV2A — modulates neurotransmitter release at hyperactive synapses but spares normal synaptic function. Does NOT affect GABA, Na/Ca channels, or NMDA receptors — fundamentally different from all other AEDs. Renally excreted unchanged (no hepatic metabolism) — no drug-drug interactions, no enzyme induction.

Formulations and products

• Keppra 250 / 500 / 750 / 1000 mg tablet
• Keppra oral solution 100 mg/mL
• Keppra XR 500 / 750 mg extended-release tablet
• Keppra IV 100 mg/mL

Storage

Tablets: 15–30 °C, dry. Oral solution: refrigerated after opening, discard 3 months. IV: 15–30 °C, do not freeze.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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Frequently asked questions