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Source overview
Recorded excerpts for one species. Each dose remains a separate source entry; no regimen is selected.
Choose one species to view its source overview. All-species evidence remains available below.
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Pending clinical review (PROPOSED)Rule-based (RULE_BASED)— applies to the facts and dose entries in this species selection; individual source records retain their own status.
Indications2
Add-on anticonvulsant for refractory epilepsy (esp. when phenobarbital/bromide fail or not tolerated); status epilepticus
DogExtra-label (EXTRA_LABEL)1 source record · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Add-on anticonvulsant for refractory epilepsy (esp. when phenobarbital/bromide fail or not tolerated); status epilepticus — Extra-label
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Add-on to phenobarbital, or sole therapy if phenobarbital not tolerated
CatExtra-label (EXTRA_LABEL)1 source record · View provenance
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Original excerpt: Add-on to phenobarbital, or sole therapy if phenobarbital not tolerated — Extra-label
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Indications table · Not applicable · Extra-label (EXTRA_LABEL) · Pending clinical review (PROPOSED) · Rule-based
Dose regimens3
This calculator performs arithmetic only on the sourced dosing field shown for each result — it does not verify the field's accuracy, does not select which field to use for a patient, and does not replace a veterinarian's order. Not for clinical use. Confirm every result against the primary source before dispensing.
Choose one species above to view its dose calculator.
Adverse effects203
Sedation — Uncommon, may be transient
DogNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Decreased appetite, lethargy, hypersalivation — Uncommon
CatNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Overall very well tolerated — —
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Side Effects / Adverse Effects table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
These are counts of spontaneously reported events, not proven adverse effects, causal relationships, or incidence rates.
Bars compare report counts within each species; they do not show incidence.
More reportsFewer reportsDog
- Seizure NOS305 reports
- Vomiting73 reports
- Death by euthanasia65 reports
- Lethargy (see also Central nervous system depression in 'Neurological')57 reports
- Ataxia48 reports
- Diarrhoea34 reports
- Elevated alanine aminotransferase (ALT)34 reports
- Lack of efficacy - NOS34 reports
- Tremor32 reports
- Death30 reports
- Increased seizure frequency29 reports
- Anorexia28 reports
Cat
- Seizure NOS18 reports
- Behavioural disorder NOS10 reports
- Death by euthanasia8 reports
- Twitching8 reports
- Ataxia7 reports
- Disorientation5 reports
- Tremor5 reports
- Dilated pupils4 reports
- Hyperactivity4 reports
- Not eating4 reports
- Other abnormal test result NOS4 reports
- Weakness4 reports
Monitoring1
Seizure diary/frequency. Therapeutic range presumed similar to humans (5–45 mcg/mL) though not veterinary-validated; check ~1 week after start, then every 6–12 months. Routine CBC/metabolic panel every 6 months.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Monitoring Parameters · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Contraindications1
Known hypersensitivity
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Precautions4
Renal impairment — adjust dose/frequency; taper slowly if discontinuing (withdrawal seizures reported in humans)
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Contraindications & Warnings table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
q8h dosing is the biggest compliance barrier — discuss realistic scheduling with owners before prescribing; XR formulation (q12h) is an option in dogs if compliance is a concern.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
"Honeymoon effect" — some dogs show reduced efficacy over time; be prepared to adjust the regimen.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
One of the safest/best-tolerated add-on anticonvulsants available — good choice when phenobarbital hepatotoxicity is a concern.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Clinical pearl · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Interactions2
Phenobarbital — Significantly ↑ clearance/↓ half-life of levetiracetam in dogs — may require higher dose or more frequent administration
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
NSAIDs (naproxen, ketorolac — human data) — Theoretical ↑ seizure risk
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Drug Interactions table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pharmacokinetics5
Bioavailability — 100%, rapid, not affected by food
DogCatNot applicable (NOT_APPLICABLE)2 source records · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
- Cat · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Protein binding — <10% (human data)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Half-life — 2–5h (avg ~3.4h) dog; ~3h cat
DogNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Dog · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Elimination — ~66% renal unchanged (human data)
Other speciesNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Other species · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Pharmacokinetics table · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Pregnancy / lactation considerations1
Human FDA category C. Use with caution in pregnant dogs/cats — high doses caused ↑embryofetal mortality and minor skeletal effects in rodent studies. Excreted in milk; safety unknown.
Species not recordedNot applicable (NOT_APPLICABLE)1 source record · View provenance
- Species not recorded · Plumb's Veterinary Drug Handbook, 7th ed., p. 723–724; Saunders Handbook of Veterinary Drugs (Papich), 4th ed., p. 442–444 — Pregnancy & Lactation · Not applicable · Not applicable (NOT_APPLICABLE) · Pending clinical review (PROPOSED) · Rule-based
Literature references19
References are linked to this drug. Species applicability is not recorded here, so the species filter does not narrow this list. Imported dates do not retain their original precision; confirm dates in the original citation.
- Evaluation of antiseizure medications including zonisamide in feline idiopathic epilepsy at a referral hospital in Japan.
Study summary not available in the imported record. Open the original citation to review the study.
- Animal Models of Drug-Resistant Epilepsy as Tools for Deciphering the Cellular and Molecular Mechanisms of Pharmacoresistance and Discovering More Effective Treatments.
Study summary not available in the imported record. Open the original citation to review the study.
- Management practices and continuing education in the treatment of canine idiopathic epilepsy among Indian primary care veterinarians.
Study summary not available in the imported record. Open the original citation to review the study.
- Delirium in critically ill patients treated with levetiracetam or brivaracetam: a comparative study.
Study summary not available in the imported record. Open the original citation to review the study.
- Levetiracetam elicits sub-chronic cardiotoxicity via modulating TLR4/MyD88 and NF-κB signaling axis: Mechanistic validation across molecular, functional, and structural endpoints.
Study summary not available in the imported record. Open the original citation to review the study.
Sources: PubMed, National Library of Medicine; openFDA, U.S. Food and Drug Administration; Plumb DC. Plumb's Veterinary Drug Handbook. 7th ed. PharmaVet Inc; 2011.
Owner information handout
Plain-language medication information to review with the owner. Open the handout to print it or download a PDF.