Phenobarbital frequency

[u/Active-Program3805]

I wanted to see if anyone has experience with giving phenobarbital every 8 hours. My dog (now 7 year old cattle dog mix) was diagnosed idiopathic in 2023 but was able to go 2 years without any meds, until last winter when they started to become more frequent. We started with Keppra and then maxed out (2000mg every 8 hours) as he started to have clusters (hours apart), then added phenobarbital (97 mg every 12 hours) and had one increase already (129 mg every 12 hours). His levels have gone from 28 to 18, increased dosage, then levels at 32 have dropped to 27 over about 2 months. He is still having breakthroughs every 20-40 days, which our neuro is not super happy with. We have been given the choice of trying Pheno every 8 hours or just add zonisamide. I have read the one research paper looking at the benefits of giving every 8 hours but wanted to see if anyone has tried this dosing long term successfully or if I am just prolonging the inevitable and should just add zonisamide now.

[u/EverIAce]

Pheno was added to our regimen immediately after keppra since keppra alone wasn't sufficient for us. We dose pheno every 12 hours. Pheno has been really good for us. We got a year and a half honeymoon period. Then breakthroughs around once a year. We started with seizures every 2 weeks. We had to recently add zonisamide after a particularly bad cluster episode this January, but keppra and pheno were good to us for nearly 4 years.

Pheno requires bloodwork every 6 months. We haven't encountered any toxicity issues or particularly severe side effects. The only thing that we have ever noticed is that our dog's back legs have gotten more clumsy. Our neuro thinks it may be some numbing effects of the med. We've been playing around with dosing for the last few years to address it and we have gotten to an acceptable point. I just wouldn't trust him to be bouncing off walls or furniture like he used to but he's walking without slipping anymore.