What Medications are Available to Treat Seizures in Dogs?
Please help me with some advices! I have a Siberian Husky female, 6 1/2 years old. When she was 8 month old, she had first seizure. The second seizure occurred after a year from first. After this, the seizures occurred often, and soon became cluster seizures. I started her medication (phenobarbital + KBr) at 5 years old and for one year she was seizures free. Unfortunately she started to seize again, one seizure at month and in last 3 times she had cluster seizures again. Because of this medications she gain in weight ( 42 kg now, 30 kg before starting medications) and I observed occasionally a tremor of her head. I want to know if i can administer zonisamide or gabapentin, and what is your opinion about this meds! How can i start with a new drug and reduce at least KBr? Please advice me. I am from Romania and 99% of vets recommend only Phenobarbitol. After this, no other medication is recommended. Thank you in advance.
There are many possible causes of seizures, but a dog who suffers her first seizure at eight months of age most likely has epilepsy. Epilepsy is a syndrome characterized by areas of excessive brain activity. The activity can spread to other areas of the brain in massive events that lead to seizures.
Most cases of epilepsy are not life threatening, but unfortunately there are exceptions. I have known several dogs (but fortunately not any cats) with progressive epilepsy that was fatal or required euthanasia.
Phenobarbital is the original, and (at least according to many experts with whom I've spoken) still the most effective anti-seizure medication. It works by tamping down excessive brain activity. Side effects include sedation (which usually wears off within a few weeks), weight gain (as you've noticed), liver damage, and possibly problems with the pancreas.
Potassium Bromide, also known as KBr, is generally the next medication used to treat seizures in dogs. It is a salt that is chemically related to table salt (heads up: the Vet Blog is going to have some more to say about chemistry soon). Many dogs tolerate KBr treatment with no side effects whatsoever (cats generally aren't as tolerant of the medicine). However, KBr can cause a plethora of side effects including sedation, head tremors (such as you have described), weight gain, pancreas problems, and respiratory problems.
Zonisamide (Zonegran), Keppra (levitiracetam), and gabapentin are relatively new medications in the world of canine epilepsy. Zonisamide and Keppra both work very well against seizures, although Keppra in particular is subject to a "honeymoon period" of seizure-free activity that can wear off. Gabapentin, in my experience, does not do much to prevent seizures.
Petru, it is clear that your dog is suffering side effects from her medications. It also appears that your dog is suffering from progressive epilepsy. I can think of a few options.
First, consider testing her blood levels of phenobarbital and bromide. These tests are widely available in western Europe; your vet should be able to draw blood samples and have them shipped to a laboratory that can run the tests. You may be able to get better control of both seizures and side effects through adjusting the medications your dog is already taking.
If that doesn't do the trick, consider adding Keppra or zonisamide. You can tell your vet that the dose of Keppra in dogs is 10 - 20 mg/kg of lean body weight (remember, your dog is not currently lean) three times daily; most experts believe that dogs can safely tolerate a much higher dose. The listed dose for zonisamide is 5 - 10 mg/kg of lean body weight every twelve hours.
Photo: no known history of epilepsy, and definitely no evidence of a weight problem.