If your dog has not had blood work done to evaluate organ function recently, that should be done. Since she has been on this medication for 12 years, that must mean that she is an older pet and we do not want to miss something that may be going on internally and simply assume it is the same old seizures that she has had in the past.
The most common anti-seizure medication used in dogs is phenobarbital. In many dogs, this will control the seizures very well. In some dogs that do not respond to phenobarbital, potassium bromide is added. Some vets will start out with potassium bromide rather than phenobarbital - and then add the phenobarbital if potassium bromide is not adequate. Either way is okay. Blood tests to determine the level of both of these medications should be done, especially if there are break through seizures, to make sure they are being absorbed properly and are at a therapeutic level within the blood stream.
There are still some dogs will continue to have seizures while on both of these medications, and there are a handful of drugs that can be tried in those dogs to see if they will respond to those. These drugs include gabapentin, Keppra, or Zonisamide.
Dilantin used to be used for seizure control in dogs but has lost favor because it does stay in the blood system for that long so it is less effective than the phenobarb or potassium bromide. Twelve years ago it was very appropriate to use, but it just isn't used much any more. While it is not necessarily a bad choice, it is just that we have better options now.
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There are new anti-seizure medications out now. Dilantin has been around since 1938, while a good drug, there may be other options. Keppra is a new anti-seizure medication that might work for her. Tegretol and Depakote are also older drugs but they work well also and these are the 'first generation' anti-seizure medications like the Dilantin.
Honestly, it depends on what type of seizures she is having also....whether it be grand mal, or partial seizures would dictate what type of medication she would need. The Tegretol and Depakote are used for pretty much the same type of seizures that Dilantin is used for. The Keppra is more for partial onset seizures in people who have epilespy, but her Dr would be the final say-so on what would work for her.
Hope this helps!
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