Antidepressants: Duloxetine at doses of 60 mg QD and 60 mg BID is effective in treatment of diabetic neuropathic pain (DNP)

Abstract

Duloxetine, a balanced and potent dual reuptake inhibitor of serotonin and norepinephrine, was found to be safe and effective in the acute treatment of pain associated with diabetic neuropathy (Goldstein et al., 2003). The objective of the study's extension phase was to examine the safety of up to 52-weeks exposure to duloxetine in comparison to routine care, and to compare the effect of these treatments on progression of diabetic complications. This was s 52-week, multicenter, open-label study extension of an acute placebo-controlled study, in which 337 patients with diabetic neuropathic pain were re-randomized to either duloxetine 60 mg BID or routine care. Diabetic complications were measured using the physical examination portion of the Michigan Neuropathy Screening Instrument (MNSI; neuropathy progression), microalbumin/creatinine ratio (nephropathy progression), and ophthalmologic examination with fundus photograph (retinopathy progression). Treatment effects on QOL were compared using the Short Form-36 and EQ-5D version of the EuroQoL instrument. There were no significant differences between treatment groups regarding neuropathy, nephropathy or retinopathy progression. Discontinuation rates due to adverse events (AEs) were 9.6% and 14.0% for routine care and duloxetine, respectively. Serious adverse events (SAEs) were reported by 19.1% of routine care patients and 14.4% of duloxetine patients. Duloxetine was not significantly greater than routine care regarding the occurrence of SAEs or AEs. There were no significant differences in the number of hypoglycemic events or treatment-emergent abnormal HbA1c or lipids. Duloxetine was significantly better than routine care on the bodily pain subscale of the Short Form 36 Health Survey and the EQ-5D Index. In this study, duloxetine 120 mg/day was safe and well-tolerated in the long-term treatment of diabetic neuropathic pain. Duloxetine was superior to routine care on several measures of quality of life.