Discontinuation Rate of Doxepin in Insomnia Patients / 정신신체의학

ABSTRACT

OBJECTIVES: We aimed to investigate the discontinuation rate and reasons of doxepin base prescription pattern in insomnia outpatients of psychiatry department of a university hospital. METHODS: 534 patients prescribed doxepin were screened. 201 patients were included and reviewed for their medical records retrospectively. The discontinuation rate and reasons of doxepin after 2 months of prescription were investigated. Patients were divided into three groups according to the prescription patterns. The initial group, prescribed doxepin as the first hypnotic, the add-on group, prescribed doxepin while maintaining existing hypnotics, and the switching group, prescribed doxepin after discontinuation of existing hypnotics. RESULTS: The discontinuation rate after 2 months of prescription of doxepin was 56.2%. There were significant differences in the discontinuation rate among three groups. The initial group had the highest while the add-on group had the lowest (p=0.018). In reasons for discontinuation of doxepin among three groups, lack of efficacy (p < 0.001) and adverse events (p < 0.001) were significantly higher in the add-on group. In the initial group, patient's refusal (p=0.022) and unknown or loss to follow up (p < 0.001) were significantly higher. CONCLUSIONS: The results of this study suggested that add-on is superior than switching method and gradual reduction of existing hypnotics is necessary to maintain doxepin treatment and prevent adverse events. Additional large scale prospective studies are needed to evaluate various factors and risks of discontinuation of doxepin.