title: An eight-year clinic experience with clozapine use in a Parkinson's disease clinic setting.
abstract: To examine our eight year clinic-based experience in a Parkinson's disease expert clinical care center using clozapine as a treatment for refractory psychosis in Parkinson's disease (PD).
  
  
  
  The study was a retrospective chart review which covered eight years of clozapine registry use. Statistical T-tests, chi-square, correlations and regression analysis were used to analyze treatment response for potential associations of age, disease duration, and Hoehn & Yahr (H&Y) score, and degree of response to clozapine therapy.
  
  
  
  There were 36 participants included in the analysis (32 PD, 4 parkinsonism-plus). The characteristics included 30.6% female, age 45-87 years (mean 68.3±10.15), disease duration of 17-240 months (mean 108.14±51.13) and H&Y score of 2 to 4 (mean 2.51±0.51). The overall retention rate on clozapine was 41% and the most common reasons for discontinuation were frequent blood testing (28%), nursing home (NH) placement (11%) and leucopenia (8%). Responses to clozapine across the cohort were: complete (33%), partial (33%), absent (16%), and unknown (16%). Age (r = -0.36, p<0.01) and H&Y score (r = -0.41, p<0.01) were shown to be related to response to clozapine therapy, but disease duration was not an associated factor (r = 0.21, p>0.05).
  
  
  
  This single-center experience highlights the challenges associated with clozapine therapy in PD psychosis. Frequent blood testing remains a significant barrier for clozapine, even in patients with therapeutic benefit. Surprisingly, all patients admitted to a NH discontinued clozapine due to logistical issues of administration and monitoring within that setting. Consideration of the barriers to clozapine therapy will be important to its use and to its continued success in an outpatient setting.
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Nawaz
authors.initials: N
authors.lastname: Hack
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America; Department of Psychiatry, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Fayad
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Erin H
authors.initials: EH
authors.lastname: Monari
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Umer
authors.initials: U
authors.lastname: Akbar
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Angela
authors.initials: A
authors.lastname: Hardwick
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Ramon L
authors.initials: RL
authors.lastname: Rodriguez
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Irene A
authors.initials: IA
authors.lastname: Malaty
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Janet
authors.initials: J
authors.lastname: Romrell
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Aparna A
authors.initials: AA
authors.lastname: Wagle Shukla
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: McFarland
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America; Department of Psychiatry, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Herbert E
authors.initials: HE
authors.lastname: Ward
authors.affiliation: Department of Neurology, University of Florida Center for Movement Disorders and Neurorestoration, Gainesville, Florida, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Okun
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000627:therapeutic use; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003024:Clozapine / Q000627:therapeutic use*; D005260:Female; D006403:Hematologic Tests; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D009735:Nursing Homes; D010300:Parkinson Disease / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D011618:Psychotic Disorders / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D012189:Retrospective Studies
chemical_list: D000978:Antiparkinson Agents; D014150:Antipsychotic Agents; D007980:Levodopa; D003024:Clozapine