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Seizures- Phenobarbital serum level
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Seizures- Phenobarbital serum level

My mothers dog has seizures - she is on Phenobarbital. The seizures are about once a month. This recent seizure there was 6 weeks in between. At times she is "dazed" for several days - other times she comes back to "normal" rather quickly.  The Vet says theres nothing we can do but continue to give her the med and if she didn't take the med it could be worse etc.

But heres the thing,,She had the level of Pheno tested in her blood and the level was low. She takes her first pill in the morning, but I figured if she took the pill and then had the blood draw - it wouldn't be a "true serum trough level."

So when the doc said the test came back low, my mother mentioned that she had skipped her morning pill until after the blood draw. The doc said "oh thats why it was low," you have to get tested again.

I don't know anything about this drug, but common sense would say that since this drug is accumulative - wouldn't the "true reading" be without taking her morning pill?  My thought would be if she had the pill just prior to the blood draw - of course the pheno level would look good. But I am guessing.

One more thing. I read that Potassium Bromide is good to give with Pheno because then you can cut back on the Pheno and the  PB doesn't cause liver damage as can the Pheno. This doc for some reason doesn't want to give her Postassium Bromide. I think the Vet just doesn't deal with alot of dogs that have seizures and may not have experience - but I could be wrong.

But anyhow, this last seizure was a "cluster" - started 2 in the morning and she had 6 of them. Its just too sad to see this and we feel helpless because all we can do is try to comfort her as she goes thru these.

If anyone has any info as far as when the best time to get the Pheno level tested and if you know anything about adding the Potas. Bromide - how much and did it help with the seizures. I printed out some info so I can go to the vet with it because I really think we should add the Bromide (especially because it doesn't damage the liver etc)

Thanks for any info/opinions,
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Avatar f tn
Hi again,
Just wanted to let you know - no biggy but, after I posted the above question, it automatically made me a member of the community and not really looking to join any communities at the moment. When I put the cursor on "leave" - it says "delete message," - and nothing happens. So you may want to contact MH and let them know there something is not working right....thanks
641243 tn?1235755684
Your doctor is right:  if you don't continue with medicine, the seizures will continue and worsen.  One seizure a month is not bad at all.  Some dogs are lucky to have one in a lifetime, one a year, one every six months...but many, many dogs would be lucky to have one a month.  If you discontinue the medicine, you will almost definitely see this frequency get higher and more severe.

The reason you need to test the blood while on Phenobarbital is because it can cause liver damage in some dogs.  Most dogs, with a consistent therapeutic level will do fine on the drug, and some develop liver disease from too high of a dosage; hence the blood tests to prevent that from happening.  Phenobarbital must be given consistently (every 8-12 hours depending on dosage instructions) for a clear, therapeutic level reading.  If a dose is skipped, the balance is off - you don't want to risk seeing too low of a level and raise the dosage cause any damage.  Your vet is looking to see at what level your dog functions normally with no side effects.  For instance, my dog started with a low dosage that did not control his seizures.  We've tested his blood before raising his dosage each time to make sure that everything is in good balance and at therapeutic levels in order to prevent putting him at any risk.  If his blood test were to come back with negative results from the phenobarbital, we would know to begin lowering the dosage to prevent any serious damage.  I was told that middle of the day testing provides the best results, so I would schedule your next blood test exactly 6 hours after his morning pill if he takes it every 12 hours.

When a dog is having side effects from Phenobarbital, or if the Phenobarbital is not working well enough on it's own, most vets will move on and add Potassium Bromide to the mix.  My dog is on this as well.  From what I understand, the Potassium Bromide helps to absorb the medicine better, and most dogs do not take just Potassium Bromide alone, but in conjunction with other anti-convulsants. Your vet probably doesn't see a need for the additional Potassium Bromide, as one seizure a month is considered "controlled" epilepsy and additional medicine does not sound necessary if your dog is not having negative effects or liver damage from the Phenobarb.  However, if the cluster seizures continue, it should probably be considered in addition to the Phenobarb.

Personally, my own experience with Phenobarb and Potassium Bromide has been to no avail.  My dog has had a very severe and difficult case of epilepsy, and after 6 months of raising Phenobarbital and adding Potassium Bromide, we added another drug called Keppra and are finally seeing results:  down to one seizure every 3-5 days, with NO clusters (his were up to 15 in a day).  

You're awesome for taking care of your mom's dog and getting her tested.  Try not to skip any more doses :)  DEFINITELY talk to the vet about Potassium Bromide if the cluster seizures continue, and if not, thank your lucky stars for only one seizure a month; it's a desirable result.
Avatar f tn
Thanks for your reply Kate.

So, anyway, I agree the dog needs to take the meds and that it would be worse if she wasn't on them,,,,but my concern is we have been getting blood tests along the way, and it concerned me that the doc never told us a "time" during the day that would be best to test to see if she is getting the correct dosage.  So with prior tests coming back with a good level I was wondering if it was a true reading because there was not that much of a change in her seizures. Seemed a little better for a while, but sometimes not.

The dose that I didn't give her wasn't meant as a "skipped dose," it was given "after" the blood draw. It just didn't make sense anymore to give it to her just before we would be going to the Vet and seeing that you said to test the level 6 hours after the pill, that would mean a late afternoon appointment and would be before her 2nd pill. That makes sense. The Vet should have told us that, so thanks for the info Kate.

A few times they were less frequent, but I still felt the meds should have helped a bit more - but as I can see now - with what you said, some seizures are difficult to control.

I just want to make sure that we are giving her all the help we could possibly give her because maybe she can be helped more if the dosage was changed - if not, then at least we tried our best and as you mentioned, once a month is a desirable result.

And, the advice you gave about the clusters and the PB - I'll mention that to the Vet too.

But anyhow, I truly appreciate your help.

I read your thread. So sorry to see the problems your dog is having. I hope the bleeding is nothing serious and that things work out soon. Glad to read the new seizure med is helping your dog. You must be a very strong person to still have your sanity after seeing your dog go thru all those seizures.

Thanks again Kate, you were very helpful,
Avatar m tn
I just came across this when googling the same question as the OP (myown).  I have a 3 yr. old female Chihuahua that has epilepsy.  Since I adopted her (at 1 yr. old), I immediately brought her to the vet to start her on Phenobarbital due to frequent seizures (sometimes a couple a day before medication started).  We had to keep increasing by half a pill( per the vet's orders due to continuing seizures) until we reached the "magic number" of 2 pills AM, 2 PM. Once she was at that dosage and combining that with Blue Buffalo Salmon dog food she actually went for 2 months without having a seizure.

I was soo excited and relieved. We finally did it and no more seizures.

Brought her in to get her pheno levels checked.  They were at 56.  Which, according to most publications (and my vet) is 15-20 points over the high end of the "therapeutic range". She doesn't show any signs of "overdose", ( she's jumpy, plays a lot,  no lethargy, etc.) so the level is perfect to control her seizures but I find out it could eventually cause liver damage. (*Cry*- Feel like no matter what I do to try and help her, there is always something else that comes up. I feel so bad for my doggy because I don't want her to have seizures but I also don't want her to die of liver damage. It very stressful and frustrating.  I don't want to lose my baby.

We had the test done sometime after she had taken her normal dose (I don't remember the exact time of day) but the pheno was definitely in her system for at least a few hours and she hadn't eaten yet that morning (due to her having surgery that day. she wasn't to eat after 6pm the previous night). So at least 16+ hours went by with her not eating and having her 7pm dose the night before and her 7 am dose the morning of her pheno test.

I was thinking maybe her pheno levels might be artificially higher than normal from not eating and also the test being run at closer to her "peak serum level".  I've heard from some vets that is a good time.  I've also heard from others you should run the test on a "low run" (before she takes her pheno) to get an accurate reading.  I can't get a straight answer on this from anyone.

To make a long story short, my doctor said to immediately cut her dosage in half (since she hadn't had a seizure in 2 months) and with the combo of her healthier diet would be a good chance she may be ok.  Literally 2 hours after I started the lower dose, seizure.  I thought..coincedence maybe?
Called my doctor immediately but it was after hours.

Next morning 1/2 dosage, 4 hours later, seizure. So I immediately gave her the other pill to prevent her from seizing again and brought her back in.We had to put her back on her normal dosage and I recommended that we try and run her levels again. What is the best time to get the most "real" reading of her level?

Since then, she has not had any other seizures with being on the 2 pills, AM, PM but I want to get another pheno level test before trying to decrease again and make sure we had an accurate reading the 1st time.  If it comes back at 30-40, or somewhere close tor the normal range, I will be super relieved.  If not, then we have to start her on another medication, while weaning her off the pheno.  

I didn't know if you are a vet, Katew888, or if this is info. you got from experience.  Anyone else has any input on this, I would greatly appreciate it.
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