This week let’s talk about the epileptic dog. There are many factors which could be affecting or causing epilepsy, and it is often hard to pinpoint the exact cause. More often than not the cases we’re going to see are idiopathic or related to a mass/tumor. So, what do we do?
Sometimes the answer is nothing. If the pet is having more than 3 seizures in a 3 month period or more than 1 per month, repeatable or long seizures lasting more than 5 minutes or within a 24 hour period or if there is an identifiable disease, that pet is a candidate for treatment.
If none of these factors are met, then we typically elect to monitor. I will often request that my clients keep a journal to better track any seizure activity, including the date, duration of seizure and post-ictal signs, and possible triggers.
It is important when starting antiepileptic drugs to establish clear goals and expectations. Complete seizure control would be ideal, and is when the patient is not exhibiting any seizures or adverse side effects.
Unfortunately, this is not always possible to achieve. Good seizure control should be our realistic goal. This is when the owner feels that the seizures are not interfering in the quality of life for their pet. An appropriate expectation would be at least 50% longer duration between seizures during a 3 month monitoring period.
There are many antiepileptic medications on the market. One of the most widely used, available and affordable options is Phenobarbital. This medication is highly recommended as it allows for reduction of seizure activity/severity in 50% of patients, and elimination of seizure activity in 33%. However, there are risks associated, which is why regular monitoring of liver enzymes is important.
What do you do in pets with liver disease? Keppra! Keppra is great as side effects are minimal, it is safer to use in pets with liver disease and more effective at managing seizure activity in pets with brain disease.
Keppra does have some down sides though. It tends to be more expensive and usually requires TID dosing. As new extended formulations are coming out on the market, some pets can get away with BID dosing.
Monotherapy is effective in most cases, but when it’s not, Zonisamide is commonly used as part of conjunctive therapy, and can sometimes give an additional 50-60% reduction in seizure activity. When do we need a second medication? When monotherapy has not provided a reduced frequency, severity or is not being tolerated well alone.
Retrievers, Shepherds, Setters, Dalmatians and Beagles more likely to require a conjunctive therapy approach. When combining medications with phenobarbital, higher doses are often required as the phenobarbital will increase the metabolism of Zonisamide and Keppra.
Potassium Bromide is still commonly used both in monotherapy and conjunctive therapy and is not metabolized by the liver! However, it can take 4 months to reach steady state concentrations. Both Phenobarbitol and Zonisamide reach steady state concentrations after two weeks.
Keppra on the other hand, never reaches a steady state (hence TID dosing). If you decide to reach for Potassium Bromide make sure to stay clear of the tablet formations as they cause pancreatitis.
There are other alternative options which can be used complimentarily, including vagal nerve stimulation, acupuncture, homeopathy, commonly using belladonna, and dietary change to increase fatty acid supplementation, encourage ketogenesis and/or use of hypoallergenic diets. These approaches are not typically effective alone and are not without risk. Belladonna can be poisonous if used incorrectly and ketogenic diets can lead to pancreatitis.
If you have a client interested in these alternative medicines, I suggest consulting with a homeopathic veterinarian before proceeding.
No matter which course of treatment and conjunctive therapies you decide to purse when treating an epileptic dog it is important to keep your primary focus on quality of life. After all, that’s why we’re doing this, to keep pets and their families happy and healthy as long as possible.
Dr. Kelly Dunham is IndeVets Area Medical Director for the Greater NYC region.