Epilepsy Drug Alternative for Canines Studied at Three U.S. Veterinary Centers
Neurologists at three centers in the United States are studying the effects of a new drug, used in human patients since 1999, on dogs with epilepsy. The goal is to recruit 50 dogs for the study, which now has 15 canines taking Keppra in conjunction with phenobarbital and potassium bromide, two drugs used in dogs for at least 20 years. These traditional treatments can cause side effects and are ineffective in controlling seizures in some dogs, said Karen Munana, DVM, a board-certified neurologist and associate professor at North Carolina State University, who spearheaded the study. “They can sometimes control seizures, but the cost you pay can be severe,” Munana said. “I wanted to find ways and treatments to get better control for dogs.”
In some dogs, both phenobarbital and potassium bromide cause sedation and unsteadiness. The drugs also can cause liver damage, Munana said. Although researchers do not yet know how Keppra works, “it seems to have a different mechanism of action than the established drugs,” Munana explained. “It tries to stabilize the hyperexcitability of the brain.”
Over the last few years, several drugs have been approved for human use to control epilepsy, including Keppra, which does not seem to interact negatively with the phenobarbital or potassium bromide given to study dogs. Primary epilepsy usually surfaces in dogs between the ages of one and five years of age, and it is one of the most common diseases, Munana said. Primary epilepsy, an inherited disease, is prevalent in several breeds, including German shepherds, Labrador retrievers, beagles and an increasing number of border collies seen by Munana. Some studies have shown genetics and breed disposition as direct causes, she added.
September marked the one-year anniversary of the study, which is being conducted at North Carolina State University, Virginia-Maryland Regional College of Veterinary Medicine and the University of Tennessee over a three-year period. The three schools have overlapping referral bases.
“The object is to see whether this anticonvulsant [Keppra] works,” said Karen Inzana, DVM, DACVIM, professor of small animal clinical sciences, who is working with three dogs in Virginia. “The owners seem to be very interested and willing to do what it takes to get this information.”
To qualify, dogs have to pass a physical and neurological exam to rule out an underlying structural cause for epilepsy and must have had at least four seizures per month while on potassium bromide and phenobarbital. Once dogs are diagnosed with primary or idiopathic epilepsy, they are enrolled in the study, which is funded by the Morris Animal Foundation, and can begin the 44-week regime. Dogs receive Keppra for 16 weeks, followed by four weeks of no drug, then 16 weeks of a placebo. Owners are asked to monitor their dog’s progress with daily checklists and fill out a questionnaire if seizures occur. Dogs are seen by the centers at eight-week intervals for blood tests that monitor the effects of the drug. No side effects or dramatic changes in blood work have yet been recorded, Munana said.
Keppra is given in conjunction with either phenobarbital or potassium bromide, though the drug has been used effectively as a sole agent in humans. Keppra would cost dog owners hundreds of dollars per month in comparison to the lower cost of the established drugs, which range from $10 to $75 per month, Munana said. For more information about referrals for the study, contact Julie Osborne, a credentialed technician, who is working with Munana.