Prescribing patterns and safety monitoring of duloxetine using the Danish Register of Medicinal Product Statistics as a source

Abstract

The safety and pattern of use of a medicinal product cannot be fully studied prior to its marketing. In Denmark, the Danish Health and Medicines Authority (DHMA) monitors marketed drugs. An available source is the Register of Medicinal Product Statistics (RMPS), which can possibly be used for these purposes. To investigate utilisation and potential safety issues of relatively new antidepressants containing the active ingredient duloxetine (Cymbalta(®) and Xeristar(®)) by using dispensing data available in the RMPS. A retrospective study using dispensing data was designed to estimate the size and composition of the user population and patterns of use of the antidepressants Cymbalta(®) and Xeristar(®) (active ingredient: duloxetine) in the period from 1 January 2005 to 31 December 2010. Data were retrieved from Epikur, a register subset of the RMPS. Both women and men in different age groups used duloxetine for depression. Some users switched to another antidepressant. Prescription of the drug for persons below the age of 18 years revealed a potential safety issue. Concomitant treatment with Cymbalta(®) or Xeristar(®) and fluvoxamine, isocarboxazid, Yentreve(®), or ciprofloxacin also revealed potential safety issues. The present study indicated that the RMPS is applicable in monitoring the pattern of use and potential safety issues related to duloxetine when it is prescribed for depression. Switching to other antidepressants could reflect some potential safety issues. Use of duloxetine for persons below the age of 18 years and its concomitant use with contraindicated drugs also indicated potential safety issues.