My son has absence seizures and complex partial seizures- he's currently on Zarontin and Keppra. He's been on Zarontin for years- it's the only one that has worked consistently for the absence seizures (cuts them about in half in frequency, which is the best we've got), and has minimal side effects. Keppra is for my son mostly for the complex partial seizures, but I think it is also used for absence seizures sometimes- but I dislike it. It has behavioural side effects, which is the worst for a kid with ASD... Obviously experiences with drugs vary a lot by individua but that's my experience.
We did also try the ketogenic diet since my son doesn't respond well to medications, but it didn't help, and since he has sensory issues with food, it was decided that limited what he ate even more wasn't overall beneficial.
I've heard about adding in vitamin B6 (I think that's for complex partial seizures though) but we haven't tried that/it has never been prescribed.
Edited to add: Good luck.
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Mum to two awesome kids on the spectrum (16 and 13 years old).