Canis ISSN: 2398-2942
Contributor(s): Kyle Braund, Lauren Trepanier
Drugs to control epilepsy
- Treatment should not follow a single seizure unless status epilepticus develops: investigation for underlying cause must precede diagnosis of idiopathic epilepsy Epilepsy: idiopathic.
- Partial seizures more difficult to control than generalized, but no drug specifically indicated for either condition.
- Aim to suppress seizures by maintaining effective concentration of drug in the brain, minimizing side-effects.
- Drugs are mainly lipid soluble, distributed readily to all tissues so plasma levels reflect tissue concentrations.
- Most drugs are liver enzyme inducers → enhance metabolism of themselves and other drugs.
- Monitor patient regularly for hepatotoxicity with phenobarbital by checking bile acids every 6-12 months, withdrawal should always be gradual.
- Phenobarbital Phenobarbital - drug of choice for canine epilepsy. Some neurologists use potassium bromide as a first line agent.
- Imepitoin Imepitoin - may have fewer side effects than phenobarbital.
- Primidone Primidone. More hepatotoxic than Phenobarbital; not recommended.
- Phenytoin sodium Phenytoin. Not useful in dogs due to short half-life.
- Potassium bromide* Potassium bromide.
- Sodium valproate* Sodium valproate.
- Zonisamide Zonisamide useful for refractory epilepsy in dogs.
- Topiramate - can be used in combination with standard anticonvulsants in refractory cases.
Drugs for status epilepticus
- Repeated seizures without periods of consciousness → emergency requiring prompt treatment or → brain damage and death.
- If cause unknown, administer diazepam* Diazepam or midazolam* Midazolam both of which cross blood-brain barrier quickly.
- Solvent (painful on IM injection) and oil-in-water preparations (painful and irritant on IV injection)
- Alternatives are pentobarbitone sodium Pentobarbital , and phenobarbitone sodium Phenobarbital.
- Recent references from VetMed Resource and PubMed.
- Packer R M, Shihab N K, Torres B B, Volk H A (2015) Responses to successive anti-epileptic drugs in canine idiopathic epilepsy. Vet Rec 176 (8), 203 PubMed.
- Podell M, Rusbridge C, Stein V, Tipold A, Volk H A (2015) International veterinary epilepsy task force consensus proposal: outcome of therapeutic interventions in canine and feline epilspy. BMC Vet Res 11, 177 PubMed.
- Peters R K, Schubert T, Clemmons R, Vickroy T (2014) Levetiracetam rectal administration in healthy dogs. JVIM 28 (2), 504-509 PubMed.
- Dewey C W et al (2004) Zonisamide therapy for refractory idiopathic epilepsy in dogs. JAAHA 40(4) 285-291 PubMed.
Other sources of information
- Plumb D C (1999) Veterinary Drug Handbook. 3rd edn. Iowa State University Press, Ames Iowa.