The aim of this study was to examine the efficacy and safety of
duloxetine, a balanced and potent dual reuptake inhibitor of
serotonin and
norepinephrine, in the management of diabetic peripheral
neuropathic pain.
Serotonin and
norepinephrine are thought to inhibit
pain via descending
pain pathways. In a 12-week, multicenter, double-blind study, 457 patients experiencing
pain due to
polyneuropathy caused by Type 1 or
Type 2 diabetes mellitus were randomly assigned to treatment with
duloxetine 20 mg/d (20 mg QD), 60 mg/d (60 mg QD), 120 mg/d (60 mg BID), or placebo. The diagnosis was confirmed by a score of at least 3 on the Michigan Neuropathy Screening Instrument. The primary efficacy measure was the weekly mean score of the 24-h Average
Pain Score, which was rated on an 11-point (0-10) Likert scale (no
pain to worst possible
pain) and computed from diary scores between two site visits.
Duloxetine 60 and 120 mg/d demonstrated statistically significant greater improvement compared with placebo on the 24-h Average
Pain Score, beginning 1 week after randomization and continuing through the 12-week trial.
Duloxetine also separated from placebo on nearly all the secondary measures including health-related outcome measures. Significantly more patients in all three active-treatment groups achieved a 50% reduction in the 24-h Average
Pain Score compared with placebo.
Duloxetine treatment was considered to be safe and well tolerated with less than 20 percent discontinuation due to adverse events.
Duloxetine at 60 and 120 mg/d was safe and effective in the management of diabetic peripheral
neuropathic pain.