A Cochrane review included 18 studies with a total of 6 407 subjects. Eight studies included a total of 2 728 participants with painful diabetic neuropathy and six studies involved 2 249 participants with fibromyalgia. Three studies included participants with depression and painful physical symptoms and one included participants with central neuropathic pain.
Duloxetine at 60 mg daily is effective in treating painful diabetic peripheral neuropathy in the short-term to 12 weeks with a risk ratio (RR) for 50% pain reduction at 12 weeks of 1.73 (95% CI 1.44 to 2.08), NNT 5 (95% CI 4 to 7). Duloxetine at 60 mg daily is also effective in fibromyalgia over 12 weeks (RR 50% reduction in pain 1.57, 95% CI 1.20 to 2.06; NNT 8, 95% CI 5 to 17) and 28 weeks (RR 1.58, 95% CI 1.10 to 2.27) as well as for painful physical symptoms in depression (RR 1.37, 95% CI 1.19 to 1.59; NNT 8, 95% CI 5 to 14). There was no effect on central neuropathic pain in a single, small, high quality trial. Adverse events were common in both treatment and placebo arms but more common in the treatment arm with a dose dependent effect. Most adverse effects were minor, but 12.6% of participants stopped the drug due to adverse effects. Serious adverse events were rare.