Levodopa and all dopamine agonists can have significant adverse
effects including hallucinations and psychosis. The incidence of
these is greater with more advanced disease and with higher doses of
medications. At their mildest these can take the form of vivid
dreams. The next stage is mild visual hallucinations with the patient
being aware of the fact that he or she is hallucinating. Visual
hallucinations are the most common and take the form of well-formed,
nonthreatening images of persons or animals. More significant adverse
effects can involve frank psychosis or delusional thinking. The
patient may be suspicious, agitated or confused. In severe cases
hospitalization may be required.

Dopamine agonists and agents with anticholinergic effects such as
Artane and Symmetrel are more likely to cause hallucinations than
Sinemet. The slow release form of Sinemet CR is more likely to cause
hallucinations than regular Sinemet.

Treatment involves lowering or stopping adjunctive agents and trying
to work with Sinemet alone as far as possible. The newer
antipsychotic agents such as Seroquel are also very helpful in
controlling severe hallucinations.