Patterns of antidepressant use among women initiating tamoxifen therapy for the treatment of breast cancer in Ontario, Canada.

Abstract

1592 Background: Depression occurs in up to 30% of women with breast cancer and often requires antidepressant (AD) treatment. Recent data suggests that concomitant use of certain antidepressants – paroxetine in particular - with tamoxifen may impair tamoxifen's effectiveness. We characterized antidepressant prescribing patterns in women initiating tamoxifen for breast cancer in Ontario, Canada. Methods: Using the Ontario Public Drug Benefit program, we identified women aged 66 years or older who initiated tamoxifen treatment between 1993 and 2005 and who had a record of breast cancer in the Ontario Cancer Registry. We used prescription records to determine the frequency, type, duration and timing of AD use during tamoxifen therapy. Results: We identified 24,430 who women initiated tamoxifen therapy for breast cancer during the 13 year study period. Of these, 7,483 (31%) received an AD at some time during tamoxifen therapy. The median age was 74 years, and the median duration of tamoxifen use was 3.39 year...