Agree with most of the above.
Try to see if reducing dopaminergic meds as an option-if it can be done without worsening the patient's Parkinson's.
The board exam answer is Clozaril--of course that is a board exam question several years old that has not been updated.
In my best clinical opinion--avoid a typical antipsychotic because of the high duration of dopamine blockage. Choose an atypical--which one? Risperdal is low on the list. It has a dopamine blockage duration on the order of typicals.
Use the CATIE trial. According to the CATIE trial Seroquel had the least amount of EPS side effects. You though still have to weigh in the fact that it has several non-EPS side effects to contend with such as weight gain, sedation & hypotension.
All of the atypicals minus Risperdal showed very little increase in prolactin--> indictaing little dopamine blockage effects.
Abilify-well Abilify is the new kid on the block & not on CATIE. Theoretically, I would think it would be a good option because its a partial agonist of dopamine, but all the studies I've seen so far concerning the use of Abilify on a Parkinson's patient, the data is sparse & equivocal.
http://www.ncbi.nlm.nih.gov/pubmed/17013906
While some patients had a favorable response, aripiprazole was associated with an exacerbation of motor symptoms. In this small study on psychosis in PD, aripiprazole did not appear promising. Copyright 2006 Movement Disorder Society.
I would also try to to assess if he has engaged in any abnormal risk taking behaviors such as gambling, or hypersexuality, as the literature demonstrates that these are common psychiatric complications of sinemet as well.
As far as I know, the data backing that dopaminergic meds increase gambling is sparse & more research is needed to verify it. I personally though find it believable. Enhance dopamine--it may enhance the effect in the nucleus accumbens. I do though agree with Anasazi that at this point, worrying about gambling in this situation is low on the list of priorities.
It has though affected my practice. I would not consider Welbutrin as a treatment option in a patient with Pathological Gambling. Besides, the limited amount of data suggests the use of an SSRI in that disorder.