How does amitriptyline work for nerve pain ?

Norepinephrine: increases the efficiency of norepinephrine and serotonin in the central nervous system which helps modulate and increase pain threshold, thus decreasing pain sensation.

Still unknown: We used to think that amitriptyline acted on the brain at the level of the thalamus or other pain interpretive centers but recent evidence points to a peripheral action site blocking C-type pain fibers- specifically, nicotinic acetylcholine receptors carrying neuropathic pain. More cool (and PRACTICAL) stuff if you want to talk about it: www.healthtap.com/drsaghafi