Is 3.75mg phenobarbital safe for my Shih Tzu puppy after a seizure?

Phenobarbital therapy in dogs is begun at 2 to 4 mg/kg twice daily. So for a 33kg dog that would mean 66 to 132 mg twice a day. We always try to start low and increase if needed but he was essentially really underdosed in the beginning with taking 30mg twice a day. He is now on a more appropriate dose. Sedation is normal when therapy is initiated but once the dog's body gets used to the drug (after about 2 weeks) he should become more like himself. If you are really worried, you can ask the vet to run a phenobarbital level blood test to see if his dosing is too high and it can be adjusted accordingly. Please be aware that dogs will never be completely seizure free even while on anti-seizure medication. Breakthrough seizures are common but they should be pretty infrequent. If he continues to seizure or does not do well on the phenobarbital there are other medication options so please work closely with your vet.

16mg every 8-12 hours is well within the safe and therapeutic range of phenobarbital for a 9 pound dog. If you were actually giving 48mg each time, this would be an overdose, and could cause coma and subsequent death. I am very sorry that Gigi died. If you would like to discuss this further, initiate a one-on-one consult and I can answer all of your questions.

Unfortunately you do not mention the weight of the dog which received the phenobarbital. A normal dose would be 2-3 mg of phenobarbital per kg (2.2 lbs) of dog. If your dog is much smaller than 6 kg (13lbs) then you need to watch it closely for the next few hours. Your dog will most likely get very sleepy. If it sleeps so deep you cannot wake it up or if you think it is not breathing properly, you will need to take it to the emergency room. If the ingestion occurred within the last hour and the amount ingested was a significant overdose, you should consider taking your dog to the emergency vet so that vomiting can be induced to get the drug out of the system. Also if your dog has liver disease, please take it to the emergency clinic.

Thank you for reaching out to Pet Coach. This should not be of major concern but may cause some mild sedation in your dog that ingested that dose unnecessarily. If your dog is on medications as well, phenobarbitol may or may not be OK to combined with those medications so that is something else to consider. As well as dogs that have decrease in liver function may process this drug a bit differently. If your springer is otherwise healthy and not on any medications, then sedation (if anything) may be the only problem.

No. Phenobarbital needs to maintain specific blood levels and the half life of the medication is 12 hours. That’s why it is dosed at that interval. You must also be careful not to over dose the medication. If you have having trouble with control of Tootsie’s seizures, I recommend to call your veterinarian. There are other medications that can be given in combination with or in substitution for phenobarbital. Follow the instructions on the label with this medication. I hope this helps and please feel free to post any additional questions.

Thanks for using Petco Pet Education Center, formerly Petcoach! Those are likely side effects from the phenobarbital. For that reason, I would highly recommend that you contact your veterinarian as they may decide to decrease his dose of phenobarbital based on this. Best of luck!

Based on the history, a toxicity seems less likely and a primary disease of the brain more likely. If the seizures are not well controlled on phenobarbital it may be that she needs a higher dose. You should discuss phenobarbital levels with your veterinarian. If the levels are in therapeutic range, a second anticonvulsant such as levetiracitam should be considered. Furthermore, you may consider following up with a veterinary neurologist to discuss diagnostics including an MRI of the brain.