The CYP2D6 metaboliser status of patients prescribed risperidone for the treatment of psychosis.
OBJECTIVE
To identify the distribution of CYP2D6 metaboliser status in patients who were being prescribed risperidone for the treatment of psychosis in a New Zealand-based clinical population.


METHODS
100 AmpliChip CYP450 Test kits were made available by Roche Diagnostics. Clinicians in mental health services across three Auckland District Health Boards were instructed that the tests were being made available for use with patients who were being prescribed risperidone for the first time. Test results were fed back to the prescribing clinician. Data analysis was descriptive in nature; however, chi-square and independent sample t tests were employed to examine differences in age, gender, and ethnicity.


RESULTS
Data were obtained for 93 patients. Poor and intermediate metabolisers each constituted 10.6% of the sample. There were no ultra-rapid metabolisers. Statistical analysis revealed no significant between-group differences with respect to age or gender. The between-group difference in ethnicity status showed a trend towards statistical significance.


CONCLUSIONS
Sample size limitations likely contributed to the finding that no statistically significant between-group differences were identified. In theory, though, for one in five patients a higher level of adverse effects might be predicted for a normal dose of risperidone, potentially leading to issues around treatment adherence or treatment failure.
Dunbar
Lucy
L
Clinical Research and Resource Centre, Waitemata District Health Board, Auckland, New Zealand. Lucy.Dunbar@waitematadhb.govt.nz
Miles
Wayne
W
Wheeler
Amanda
A
Sheridan
Janie
J
Pulford
Justin
J
Butler
Rachael
R
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D010641:Phenotype; D011110:Polymorphism, Genetic; D011618:Psychotic Disorders / Q000188:drug therapy* / Q000208:ethnology / Q000235:genetics*; D018967:Risperidone / Q000627:therapeutic use*; D044465:White People / Q000235:genetics
D014150:Antipsychotic Agents; D019389:Cytochrome P-450 CYP2D6; D018967:Risperidone