I currently take 600mg of zonisamide (generic Zonegran) for peripheral neuropathy prescribed by my neurologist. My regular PCP had me on 300mg for three years. It worked for about a year and a half, then the effectiveness started to wane. I'm wondering if the same thing will happen with the 600mg which is the max allowed FDA dose. I found that when taking zonisamide (generic Zonegran), the side effects along with the medication benefits is largely dependent on the drug manufacturer. Does anyone else taking zonisamide have a similar experience?