Polypharmacy prevalence rates in the treatment of unipolar depression in an outpatient clinic

Abstract

Objective: Unipolar depression is a complex illness with an ever increasing number of pharmacological treatments available. As the number of available medication options increases, so does the potential for polypharmacy, a practice with possible complications. Such complications include a greater number of side effects with the initiation of additional medications and the consequences of drug-drug interactions. Therefore, it is important to understand the effects of polypharmacy on efficacy of treatment as well as whether polypharmacy is instituted after appropriate initial monotherapy trials. This study attempts to answer these questions.

Methods: Patient names for this investigation were provided by residents in the UMass Medical School Psychiatry Residency program. The charts of these patients were analyzed to collect data regarding demographics, clinical data about the illness, medication names, types, duration of use and to access efficacy using the Clinical Global Impression (CGI).

Results: Of 160 reviewed charts, 135 subjects were included in the final analyses (others excluded due to incomplete data or no depression diagnosis). Patients were on average on 2.0 medications (SD=0.5) with 2.1 past trials. A greater number of current antidepressant medications did not correlate with a greater improvement in CGI, implying that polypharmacy did not necessarily lead to greater efficacy. The impact of illness severity, as measured by comorbidities, substance abuse, and trauma history, were included in the analysis, and did not significantly change this outcome. Additionally, prescription patterns themselves were examined, including reasons for termination of medication trials, the impact of side-effects, and the number of patients that had complete monotherapy trials before transitioning to polypharmacy.

Study limitations: Small sample size, retrospective review, one CGI rater.

Conclusions: First, many patients did not receive an adequate monotherapy trial, as defined by dose and duration, before progressing to polypharmacy. Secondly, the use of two or more medications concurrently did not appear to increase efficacy as measured by CGI. Due to study limitations, direct comparison of the efficacy of one and two medications was not significant; however the study did demonstrate a general correlation between polypharmacy and greater depressive symptomatology. This suggests the need for optimizing monotherapy regimens before initiating polypharmacy that may not lead to improvement in symptoms.