Medical Management of Recurrent Seizures in Dogs and Cats

Abstract

The problem o€ recurrent seizures is a common and challenging one in veterinary medical practice. The pathophysiology and pharmacologic suppression of focal seizure activity have been studied extensively in basic research settings, yet little is known of the genesis, modulation, and termination of generalized seizures, the most common form of seizures noted to occur in companion animals. Knowledge concerning the pharmacokinetic fate of anticonvulsant drugs currently used in veterinary medicine is adequate, though prospective clinical studies of the efficacy of these drugs in the treatment of various types of seizures are lacking. This study will review the available literature regarding the pharmacology, use, and side effects of anticonvulsant drugs currently available for control of recurrent seizures in companion animals. Alternative anticonvulsant drugs will also be described. (Journal of Veterinary Internal Medicine 1990; 4:26-39) Pathophysiology of Seizure Generation SEIZURES are the clinical manifestation of rapid, excessive electrical discharge of neurons in the brain. Seizures may be classified by site of origin as primary (idiopathic, genetic) or secondary (acquired, symptomatic). The term epilepsy refers to recurrent seizures of intracranial origin. How seizure activity is expressed clinically, whether as localized or geneFalized motor or nonmotor (psychic, autonomic) activity, may determine the group of anticonvulsant drugs that would be appropriate for therapy, especially in human patients.In the normal resting state, the electrical difference across neuronal cell membranes is maintained by an active sodium-potassium pump, the net effect of which results in a resting membrane potential ( R M P ) of -70mV.' Transmission of changes in the RMP along axons ultimately causes release of a neurotransmitter with either excitatory or inhibitory effects on a network of postsynaptic neurons that includes adjacent and distant cells. A collateral feedback system allows each neuron to also influence its own excitability. Excitability is mediated by energy-dependent influx of sodium into

Polymorphisms in the ABCB1 Gene in Phenobarbital Responsive and Resistant Idiopathic Epileptic Border Collies

“…However, among epileptic dogs treated with standard antiepileptic drugs (AED) such as phenobarbital (PB) or potassium bromide (KBr), 25-30% are resistant to treatment despite adequate doses and serum concentrations of AEDs. 2,3 This finding is similar to that in humans where one-third of epilepsy patients do not respond adequately to AEDs. [4][5][6] Recently, a new definition of drug-resistant epilepsy in humans was proposed by the International League Against Epilepsy as failure of adequate trials of 2 AEDs to achieve sustained seizure control.…”

Surgery in Epilepsy – How Advances in Human Neurology can benefit Veterinary Patients

“…In UK, this prevalence was estimated to be 0.62% (Kearsley-Fleet et al, 2013). Drug-resistant canine epilepsy has been previously reported to affect as high as 30% of all dogs with idiopathic epilepsy (Lane and Bunch, 1990). …”

The Nervous System

“…[49][50][51] The following therapeutic rules often assist in the clinical management of refractory seizures in older dogs.…”