Factors predicting high-dose and combined antipsychotic prescribing in New Zealand: High-dose antipsychotic prescribing.

OBJECTIVE: Guidelines recommend using antipsychotic monotherapy at the lowest effective dose, however high-dose and antipsychotic polypharmacy prescribing (APP) remain commonplace. The aim of this study was to determine the prevalence and patterns of high-dose antipsychotic prescribing and APP among mental health service users in New Zealand (NZ). METHODS: A retrospective audit of service users discharged from inpatient (n=657), or registered with community (n=1560), mental health services at Auckland District Health Board was undertaken. Case notes were reviewed and data on demographics, antipsychotic routes and doses were collected. Outcomes measures included: frequency of total high-dose prescribing, high-dose monotherapy, APP, high-dose APP, and factors associated with these prescribing practices. Logistic regression models were used to examine the relationships between explanatory and outcome variables. RESULTS: Of the service users prescribed an antipsychotic (n = 2217), 14% were prescribed a high-dose antipsychotic. The frequency of high-dose monotherapy, APP, and high-dose APP was 3%, 26% and 11%, respectively. Being male, Maori, on compulsory treatment, having a schizophrenia diagnosis, or being prescribed polypharmacy were associated with high-dose antipsychotics. Olanzapine was most frequently prescribed in both high dosing (55%) and APP (40%). CONCLUSIONS: There is a high prevalence of high-dose prescribing and APP in this NZ setting.

Mood stabilizer loading versus titration in acute mania: audit of clinical practice.

OBJECTIVE: The aim of the present study was to investigate whether the use of a loading strategy with lithium or valproate followed recommended practice and second, whether this had any impact on indicators of outcome in acutely manic inpatients. METHOD: A 12 month retrospective review of admissions to two adult psychiatric units in Auckland, New Zealand, was conducted. Demographic, legal status, psychiatric admissions, outcome indicators (length of stay, intensive care and seclusion use) and medication data were collected for all patients with a diagnosis of acute bipolar mania who started mood stabilizer treatment within 3 days of admission (n=93). Serum levels and adverse effects were also recorded. RESULTS: In 46.2% of admissions a loading strategy was prescribed, and lithium was the treatment choice in two-thirds of admissions. Serum levels were taken inconsistently, particularly for valproate. No difference was found between loading and titrating for the assessed outcomes in routine practice; average length of stay was 30.2 days; most patients (71.0%) spent time in intensive care (average 8.4 days) and 33.3% spent time in seclusion. More adverse effects occurred with loading (51.2%) compared to titrating (36.0%), particularly with lithium. CONCLUSION: The literature supports a strong link between rapidly attained high serum levels and positive outcomes. The present study found inconsistent and infrequent measurement of levels, which was not in accord with recommended practice. Frequent monitoring of serum levels to support dosing decisions is important to inform better clinical decision making, especially when a loading strategy is used. This may explain the less than optimal outcomes (with respect to rapid resolution of mania and hospital discharge) that were found, irrespective of dosing strategy.

Olanzapine vs risperidone in the management of schizophrenia: a randomized double-blind trial in Australia and New Zealand.

Improved drug therapy for schizophrenia may represent the best strategy for reducing the costs of schizophrenia and the recurrent chronic course of the disease. Olanzapine and risperidone are atypical antipsychotic agents developed to meet this need. We report a multicenter, double-blind, parallel, 30-week study designed to compare the efficacy, safety, and associated resource use for olanzapine and risperidone in Australia and New Zealand. The study sample consisted of 65 patients who met DSM-IV criteria for schizophrenia, schizoaffective disorder, or schizophreniform disorder. Olanzapine-treated patients showed a significantly greater reduction in Positive and Negative Syndrome Scale (PANSS) total, Brief Psychiatric Rating Scale (BPRS) total, and PANSS General Psychopathology scores at endpoint compared to the risperidone-treated patients. Response rates through 30 weeks showed a significantly greater proportion of olanzapine-treated patients had achieved a 20% or greater improvement in their PANSS total score compared to risperidone-treated patients. Olanzapine and risperidone were equivalent in their improvement of PANSS positive and negative scores and Clinical Global Impression-Severity of Illness scale (CGI-S) at endpoint. Using generic and disease-specific measures of quality of life, olanzapine-treated patients showed significant within-group improvement in most measures, and significant differences were observed in favor of olanzapine over risperidone in Quality of Life Scale (QLS) Intrapsychic Foundation and Medical Outcomes Study Short Form 36-item instrument (SF-36) Role Functioning Limitations-Emotional subscale scores. Despite the relatively small sample size, our study suggests that olanzapine has a superior risk:benefit profile compared to risperidone.