Palmitoylethanolamin (een PEA-houdend product®) is a endogenous lipid with analgesic and anti-inflammatory properties. In a study were 30 patients were entered, suffering from diabetic neuropathic pain and post-herpetic pain, palmitoylethanolamide was combined with pregabalin (Lyrica®) in the treatment of neuropathic pain.
The dose of palmitoylethanolamide was twice 600 mg; pregabalin was slowly titrated in a bid dose regime, starting with 150 mg/day, after 10 days to 225 mg/day, after 10 days to 300 mg/day and again after 10 days up to 400 mg/dag.
The therapy with pregabalin and palmitoylethanolamide significantly improved pain, functional disability and sleep in a pre versus post comparison. Important to note was: there were no tolerability issues, and the impression that tolerability of pregabalin improved by adding palmitoylethanolamide. 
Source: http://www.neuropathie.nu/treatment/palmitoylethanolamide-een PEA-houdend product-combined-with-pregabalin-in-neuropathic.html