Nuplazid treats hallucinations in Parkinson's disease psychosis.
FDA approved Nuplazid in 2016 as a serotonin receptor antagonist.
Reports cited 244 deaths linked to Nuplazid between 2016 and 2017.
Lawsuits claim Nuplazid caused severe side effects without proper warnings.
FDA maintains a boxed warning on Nuplazid about the risk of death in elderly.