Pimavanserin Relieves Psychosis in PARKINSON’S DISEASE






The result of a Phase III study that was released on November 1, 2013 demonstrated that Pimavanserin was effective in relieving symptoms of psychosis in people with PARKINSON’S DISEASE without worsening the other symptoms of the disease.  Pimavanserin is a new type of anti-psychotic drug that works by blocking the receptors for serotonin in areas of the brain that connect sensory perceptions and conscious thoughts.

Psychosis in people with PARKINSON’S DISEASE is not an uncommon occurrence.  It is a very serious issue that makes caregiving in the home nearly impossible and results in the admission of people with PARKINSON’S DISEASE to long term care facilities where they can be monitored day and night.  Prognosis is not good, and often marks the beginning of serious decline.

Hallucinations usually manifest as rather benign hallucinations, often of children or  seeing “little people”, but can sometimes be much more serious with visions of malevolent intruders or assume sexual overtones.  Long time use of anti-parkinson’s medications, such as levodopa replacement therapies is thought to be at least part of the cause as well as the disease pathology itself.  Sleep disturbances are also a major contributor to psychotic symptoms.  Newer studies have shown there are other irregularities in the white matter fibers of the brain that also contribute to psychoses in people with PARKINSON’S DISEASE, but whether the damage to white matter fibers is caused by the disease or contributes to the disease has not been clearly elucidated.

Neurologists’ usual response to hallucinations is to reduce levodopa to the lowest effective dose possible, and if that does not solve the problem, then to introduce antipsychotic medications.  Seroquel (quetiapine) is often the first drug of choice, but clinical trials have shown very limited benefit.  Clozaril is also a possible candidate, however it requires bi-weekly blood draws to monitor liver function, a major drawback for the already compromised lives of people with PARKINSON’S DISEASE.  Anti-depressants have sometimes shown good results, and certain anti cholinergic medications have also sometimes been effective, but side effects have been problematic.

Pimavanserin has been developed by the pharmaceutical company Acadia.  The Food and Drug Administration has agreed that the studies thus far conducted have been favorable and they are allowing Acadia to go forward with filing a New Drug Application.  A few more supportive studies must be undertaken before approval can be granted, but the company is focused on moving ahead to obtain FDA approval as quickly as possible.


News release from Acadia Pharmaceuticals


Article by Marcia McCall


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