Factors affecting discontinuation of initial treatment with paroxetine in panic disorder and major depressive disorder

Abstract

Akiko Aoki,1 Shin Ishiguro,1 Takashi Watanabe,1 Mikito Ueda,1 Yuki Hayashi,1 Kazufumi Akiyama,2 Kazuko Kato,3 Yoshimasa Inoue,1 Shoko Tsuchimine,4 Norio Yasui-Furukori,4 Kazutaka Shimoda11Department of Psychiatry, 2Department of Biological Psychiatry and Neuroscience, Dokkyo Medical University School of Medicine, Tochigi, Japan; 3Sakura La Mental Clinic, Tochigi, Japan; 4Department of Neuropsychiatry, Hirosaki University Graduate School of Medicine, Aomori, Japan Objective: The aims of the present study were to analyze the association between discontinuation of paroxetine (PAX) and the genetic variants of the polymorphism in the serotonin ­transporter gene-linked polymorphic region (5-HTTLPR) in Japanese patients with panic disorder (PD) and major depressive disorder (MDD).Methods: The 5-HTTLPR genotype was determined by polymerase chain reaction method. PAX plasma concentration was measured by high-performance liquid chromatography to confirm adherence.Results: When comparing between the PD and MDD patients with the chi-square test and Fisher’s exact test, the PD patients had a significant and higher discontinuation rate due to nonadherence than did the MDD patients (13.5% [7/52] versus 0% [0/88], respectively; P<0.001). MDD patients had a significant and higher discontinuation rate due to untraceability than PD patients (12.5% [11/88] versus 1.9% [1/52]; P=0.032). Multilogistic regression revealed a tendency for the long/short and short/short genotypes to affect discontinuation due to adverse effects in PD patients (25.0% versus 6.3%, respectively; P=0.054). Conclusion: The results indicate that the 5-HTTLPR genotype might contribute to the discontinuation of initial PAX treatment due to adverse effects in PD patients. Keywords: paroxetine, discontinuation, panic disorder, major depressive disorder