Survey of Depot Antipsychotic Prescribing in Southern Adelaide

Abstract

Depot antipsychotic medication (DAP) is widely used in the treatment of schizophrenia and related disorders. The objectives of this study were to (i) determine whether DAP was being prescribed in accordance with established guidelines in terms of dose, interval of administration and indications; and (ii) assess the quality of the assessment and documentation of tardive dyskinesia (TD) as well as blood glucose and lipid abnormalities. The survey was carried out between April and June 2003 at all three public hospital affiliated community mental health centres located in the southern region of Adelaide. Data were extracted from three sources: depot prescription charts, community mental health service case notes and hospital case notes. Two hundred and sixty-one patients were receiving DAP. The majority (89%) had a diagnosis of schizophrenia or schizoaffective disorder. The DAP prescribed most frequently was zuclopenthixol decanoate (57%) at a modal dose of 200 mg and a modal administration interval of 2 weeks. Fifty-three per cent of patients had at least one dose reduction during the course of treatment. Four per cent of patients had a case note documented diagnosis of TD. Fifty-seven per cent of patients had at least one blood glucose test in the past year, with nearly half showing high results. Forty-seven per cent of patients had at least one lipid study in the past year, with more than half having high total cholesterol and 22% having high triglycerides. The results of this study indicate that DAP is being used mostly for the treatment of schizophrenia and related disorders, which is in agreement with established evidence-based guidelines. The finding of at least one documented attempt at DAP dose reduction or extension of interval of administration in approximately half of the patients receiving DAP is encouraging and may have an impact on reducing the likelihood of TD. A formal TD surveillance programme using a screening tool such as the Abnormal Involuntary Movement Scale is recommended. In addition, more frequent evaluation of blood glucose and lipid levels is needed.