I've been using a low dose (10 mg) of amitriptyline to help sleep through the night. It doesn't help my PN any, but it is known to help chronic pain patients in this way.
amitriptyline for sleep problems
My wife has been taking L-tryptophan for SNRI withdrawal. At bedtime, this turns into melatonin, which is helping her sleep. Taking that with melatonin would be redundant.
Doc