@janwill
When he was taking 1000 mg a day how much did you cut his Keppra and how often to get to 500 mg? Many doctors cut meds by 50% but I never cut medication by 50%. The nausea could be caused by decreasing the Keppra too quickly. Unfortunately, doctors have a bad habit of doing that. Is your son taking the immediate dose or the extended release version? How long has he been taking Keppra?
Take care,
Jake