Specific side effects of long-term imipramine management of panic disorder

In a recent study, the authors suggested that tachycardia, dry mouth, and sweating continued to burden patients with panic disorder with agoraphobia who have shown marked and stable response to 6 months of imipramine treatment at the fixed, weight-adjusted dose of 2.25 mg/kg/day. Although sexual dysfunction and weight gain were not a significant burden in that study, they are important problems in long-term treatment with antidepressant drugs. In the present study, in the context of a randomized, double-blind, placebo-controlled, 1-year discontinuation and maintenance study of 53 patients with panic disorder with agoraphobia who respond to imipramine, the authors examine the extent and the specificity of these five side effects of imipramine maintenance using data at pretreatment, at the end of 24 weeks of open imipramine treatment (or month 0 of randomization), and at months 2, 4, 6, 8, 10, and 12 of randomized treatment. Hierarchical linear modeling and repeated measures of analyses of variance in subsamples of completers confirmed that dry mouth, sweating, and increased heart rate constitute a significant and specific enduring burden of imipramine maintenance treatment. The data also revealed that weight gain is a significant and specific side effect of 1-year imipramine maintenance treatment; however, the likelihood of reporting sexual dysfunction decreased over time, with no difference between the placebo and imipramine maintenance conditions. The results are discussed in the context of previous studies of imipramine side effects in the management of depression and the available literature of sexual and weight side effects of antidepressant medications in the treatment of anxiety disorders.