Phenobarbital side effects--how long?

[jtrosen]

My dog (shepherd/husky mix, 73 pounds, 12 years old) began to have grand mal seizures last week. He had two seizures, one on Sunday and one on Monday, at almost exactly the same time in the evening. After the second seizure, the vet put him on phenobarbital (97 mg/2x per day).

He's been on it for five days now and is still pretty out of it. He is extremely lethargic (sleeps most of the day), has coordination problems, and weakness in his hind end. He walks veeery slowly. He's also extremely hungry and thirsty. I've read that all of these are possible phenobarbital side effects. How long do these usually last before the dog gets used to the medication? I'm hoping that these are not signs that something else is wrong, though I am aware of the possibilities.

[WhitneyMac]

Also, I did some research on her flea/tick prevention. I feel this could have been an issue as well.

We have been taking Sugar to Banfield and they prescribed her FirstShield, which is a Banfield product. Her seizures did not begin until we began giving her First Shield. Both times the seizures happened within 2 weeks of giving her this medicine.

I am not sure if you are familiar with FirstShield but the reviews are VERY disturbing to say the least. We also noticed after reading about the medication and what to look for she had other reactions from the medications. Chemical burns and hair loss along the application site.

We have taken her off this as well. I am contemplating weaning her off the phenobarbital and seeing if it was a direct effect of the FirstShield as i read it caused seizures in many dogs.

[WhitneyMac]

I apologize for the delay, I reached out to so many different groups it seems i had lost track of this one.

Update - Sugar has now been on the Phenobarbital for almost a month. (We started her June 30th) She is still seizure free, however the barking has not stopped. It has gotten a little better, I suppose. She still barks continuously until we go to bed. We ignore her the best we can until she stops barking and then reward that behavior. It does stop it for a short period of time. During the night she wakes up between 2 and 3am, goes potty, has a barking fit for about 30min-1hr and goes to sleep until between 6-7 and wakes up barking again. Once I get out of bed for work, about 7:20 the barking stops. She gets up and just watches me get ready, following me around the house.

We just took her to the vet last Wednesday and said her levels are "fine" and are continuing with the same dosage of the Phenobarbital. They have tried to suggest the barking is just because shes old. However I refuse to settle for that answer as it absolutely did not start until she was on the medicine.

As far as the renal failure, i am guessing she is at stage 3 from what I have read. I read that you really cannot tell from blood work until it gets to stage 3. Again, I could be wrong, but this is from what I have read.

The vet we have been going to was great with our other dog, but I feel since Sugar needs more attention and more specific treatment they are not qualified. I have another appointment for her on Saturday with another vet.

Do you think the phenobarbital could be causing this issue at all? Again, her kidney levels are almost normal still just with the renal food. We have also as of last week discontinued the steroid for her itching and have her on Hydroxezime (antihistamine)

I guess, my point of this is to get some advice on where and how to proceed with the vet on suggestions for medicines etc. The other vet did not seem open to anything and stated she had to be very careful due to the renal failure.

[tonyb286]

Hi. That is a really complex group of illnesses. The anxiety barking may of course be directly linked to the side effects of phenobarbital or indeed minor (petit mal) seizures that are making her feel insecure and/or afraid. When did she last have her bloods checked? It would certainly be worthwhile, so your vet has some idea about whether the dose is high, low or at the appropriate level.

Also, what stage is the renal disease? If it is late stage 3 or stage 4, there is going to be an impact caused by the anticonvulsant drug. This may mean the renal failure is going to deteriorate more rapidly.

As she is already on phenobarbital, it may be worth your vet prescribing a suitable "calming" medication. Ordinarily, with renal failure, this is not something advised, as it will cause more toxins to be produced - but in this case, it's unlikely to make much difference to the outcome, so something probably worth trying.

Tony

[WhitneyMac]

PLEASE HELP!

I rescued the sweetest westie mix in December of last year. However, a few months later we found out she had renal failure, since then we have managed the problem with Royal Canine LP. Our next issue was allergies, she is now on a steroid for this. Just recently, she started having seizures.She had 3 back to back seizures so now we have her on the Phenobarbital and since she has been seizure free. She has only been on the medicine a little over a week, but I am going insane. I know most of the side effects are normal, the weak legs, thirst, excessive urination etc. HOWEVER, she is barking...NON STOP. She paces, barks/howls/whines for 2 hours, sleeps for 30 minutes, paces, barks/howls/whines for 2 hours, sleeps for 30 minutes. We have a camera on her during the day and have noticed she sleeps just fine when no one is home. It only begins once we get home and literally does not stop until we leave again the next morning regardless whether we are awake, up moving, or asleep. Anyone have any ideas on how to ease the anxious barking?!

[tonyb286]

Hi. Side effects can last up to around 8 weeks, though most dogs respond within 4 weeks. The point is, your vet is absolutely right, do not reduce the phenobarbital and make sure you never miss a dose, and give the doses at exactly the same time every day (usually 12 hours apart). You just have to be patient. The side effects will eventually dissipate. You didn't wait long enough the prior time (2 weeks I think), and had you continued with the dosage, the side effects would have reduced and disappeared within the 8 week framework. Your vet is also right that this could be a brain tumor (most common cause in older dogs, particularly boxers). You could have tests to determine whether it is or not, but I tend to agree with you, it would be stressful to consider treatment for it and, given her age, probably not a good idea.

Tony

[hkruskamp]

I have been reading through the posts and am happy to have found a place to discuss the issues we are having with our dog. She is a 12 to 14 year-old boxer/bulldog mix (we believe - she's a pound puppy). About 5 weeks ago she began to have seizures following the removal of a mast tumor on a back leg. The vet initially thought the seizures may be due to the large amount of benadryl she was on. We started pb at 1.5 pills twice a day and she became very drunk seeming - can barely walk, very stumbly, maybe a bit confused. This went on for a couple weeks when we began to slowly ween her off the pb. When we got down to .25 pill 2/day she began to have seizures again, having about 8 in a 36 hour period, including at the vets office. The vet told us that it is very likely a brain tumor. Because of her age we are not going to treat the tumor, but want her to enjoy the rest of her days. The vet told us to up the pb dose back to 1 pill 2/day. She has not have a seizure since. That was about a week ago, but again, she can't walk well - is very stumbly, has to be carried to food, water, and outside. I'm concerned that this side effect will not wear off since it didn't wear off before and the vet has told us that we shouldn't consider a lower dose again. How long should we keep her like this? Could she still be happy? It's heartbreaking to watch, but of course I don't want to let her go if there's a chance she'll get better. Has anyone dealt with this sever side effect before? She's been such a wonderful, loving dog. It tears me up, but I want to do the best and most loving thing for her. Thanks for any thoughts.