A medication prescribed to treat either psychosis or nausea. Perphenazine (Trila-fon) is a dopamine antagonist. It nonselectively blocks dopamine receptors throughout the BRAIN including the basal ganglia, where this effect counteracts levodopa and dopamine agonists in people who are taking it for Parkinson’s disease and can cause a Parkinson’s crisis (sudden and severe worsening of motor symptoms). It also has strong anticholinergic actions, which give it its effectiveness in mitigating nausea. Perphenazine is an old drug, on the market since the late 1950s. There are many newer medications to treat either psychosis or nausea that do so without the high risk of extrapyramidal consequences. The person with Parkinson’s disease should not use per-phenazine. Perphenazine cannot be taken with LEVODOPA or DOPAMINE AGONIST MEDICATIONS such as BROMOCRIPTINE, PRAMIPEXOLE, ROPINEROLE, OR PERGOLIDE.