My wife was on Zonisamide for about 3 years. Her MDS discontinued it a few months ago because we thought it wasn't doing much good. The MDS put her on Rytary which seems to prolong her on times but she still needs about 3 fast relief Sinemet each day. She is well over the equivalent of 1200mg CLD.
She was on low dose naltrexone, LDN, for about 6 years (started 11 years ago) and it did not seem to help. Her PD has advanced to where she has serious hallucinations and delusions. She just started Nuplazid for PD psychosis. She is not a candidate for DBS because of psychosis.