Paroxetine improves pain and depression in patients with refractory chronic pain

Abstract

Objective: Patients with chronic pain frequently have depression, which may augment their pain. The selective serotonin re-uptake inhibitor, paroxetine, is widely used in the treatment of depression. The purpose of this study was to examine the effectiveness of paroxetine in the treatment of refractory chronic pain. Patients and methods: Fifty patients with a history of at least 6-month persistent chronic pain participated in this study. Paroxetine was orally administered once daily at a dose of 10 mg initially, then increased weekly by 10 mg until a maximum of 40 mg. The dose was reduced when an adverse reaction occurred, and treatment was continued for 2 weeks at the optimal dose. Depression was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). The state of depression was evaluated using the Self-Rating Depression Scale (SDS), and that of pain using the Visual Analogue Scale (VAS). Results: Overall, 70% of the patients had depression. The SDS score was higher in patients with depression compared with non-depressed patients. Treatment of patients with depression by paroxetine resulted in reduction of VAS score to less than half, concomitant with a decrease in SDS score. Paroxetine also significantly reduced the VAS scores in non-depressive patients. However, the decrease in VAS score was more marked in patients with depression compared to those without depression. Conclusions: These results suggest that a large proportion of patients with refractory chronic pain has depression and paroxetine improves both the depression and chronic pain.