Pharmacotherapy prescribing patterns in the treatment of bipolar disorder in an outpatient population at Tara hospital

Holzapfel, Eleanor
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Introduction Pharmacotherapy is a key component in the management of bipolar disorder. Whilst one might aim for fewer agents, not all patients with bipolar disorder can be stabilized with monotherapy and combination treatment (polypharmacy) is increasingly used to manage patients in clinical practice. Mood stabilizers have traditionally been prescribed as monotherapy, however the use of atypical antipsychotic agents is seen in clinical practice with various such agents approved for such usage. Combination treatment with an antipsychotic, preferably an atypical antipsychotic together with a standard mood stabilizer is also noted in clinical practice as well as recommended by guidelines. Bipolar patients managed in a specialist psychiatric setting have a greater chance of being managed with polypharmacy than in a general practice setting. The use of polypharmacy may also be attributed to receiving treatment in an academic environment. This current study was based on the application of diagnostic criteria and principles of the Diagnostic and Statistical Manual of Mental Disorders version IV TR (DSM IV TR), published by the American Psychiatric Association and The International Classification of Diseases version 10 (ICD 10), published by the World Health Organisation. Aims The study aims to describe the range and frequency of medications used in the management of bipolar bisorder in a specific setting as well as describe the nature and frequency of monotherapy versus polypharmacy use. Hypothesis The study hypothesized that the majority of patients attending the specialist / academic psychiatric outpatient clinic at Tara Hospital would be prescribed polypharmacy and that antipsychotics (typical or atypical) would be prescribed in combination with standard mood stabilizers in the majority of cases. Method The study took the form of a retrospective patient file review. The clinical files were for patients attending the Tara Hospital psychiatric outpatient clinic. The files of every patient who attended the clinic at least once in 2009 were screened and included in the study where the recorded ICD 10 code corresponded with a bipolar disorder subtype or a single manic or hypomanic episode. Where the recording of the ICD 10 code was missing or incomplete further scrutiny of the clinical notes enabled the researcher to establish a diagnosis of bipolar disorder using the ICD 10 and/ or DSM IV TR diagnostic criteria and therefore include the patient file in the study. Other necessary information was obtained by reviewing clinical notes as well as the prescription written on the last patient visit for 2009. Results The study found that the majority of patients (93.8%) were prescribed polypharmacy, with 3.2 the mean number of psychotropic medications prescribed per patient. Lithium was prescribed in 34.3% of patients. Sodium valproate was prescribed in 37.1% of patients. Eighty three point eight percent (83.8%) of the patients were prescribed at least one standard mood stabilizer. The atypical antipsychotics (46.6%) were prescribed more frequently than the typical antipsychotics (16.5%). Lamotrigine (31.8%) was the preferred novel anticonvulsant and the selective serotonin reuptake inhibitors (SSRI’s) were the most commonly prescribed antidepressant (28.9%). Clonazepam (26.8%) was the most frequently prescribed benzodiazepine add-on. The use of combination treatment to manage bipolar disorder was the rule rather than the exception. There was however much variety in the combinations used with no particular combination being prescribed in the majority of patients. Forty seven percent (47%) of the combinations used included a standard mood stabilizer and a typical or atypical antipsychotic. Conclusion The current study provides preliminary data on the prescribing patterns in bipolar disorder in a specialist psychiatric clinic within an academic complex in South Africa. The findings are in keeping with international studies and highlights that polypharmacy and combination treatment in the management of bipolar disorder is the norm in such settings. There is a large variation in clinician practices and much variety seen in the combinations of medications used to treat bipolar disorder despite the availability and use of treatment guidelines. This is perhaps because bipolar disorder is such a complex disorder and that most of the treatment recommendations are based on limited data. Treatment guidelines have emerged in order to attempt to standardize treatment and provide clinicians with algorithms to utilize and apply research findings in daily clinical practice. Further study into the effective prescribing principles for bipolar disorder is necessary.
A research report submitted to the Faculty of Medicine, University of the Witwatersrand Medical School, in partial fulfilment of the requirements for the Degree Masters of Medicine in the branch of Psychiatry, Johannesburg, August, 2015