Muhammad Tariq, Salman Ahmad Saleem, M Salim.
Neuropathic Pain.
J Coll Physicians Surg Pak Jan ;11(9):591-7.

It is generally accepted that neuropathic pain is caused by nerve injury. It has been discovered that nerve damage can change the biochemistry, and even the anatomic organization of not only primary sensory afferents but also spinal and even brain neurons. The reorganization suggests that efforts to explain neuropathic pain on the basis of normal pain processing are at least partly misguided. Each form of pain sensation will have to be studied on its own terms. On the other hand, the reorganization explains that drugs effective against normal pain can be ineffective against neuropathic pain, whereas drugs effective against neuropathic pain tend not to be analgesic in the ordinary sense. Because the neuropathic pain circuits are in many ways a new system, certain drugs will affect the neuropathic pain circuit but not the old system. The past decade has seen the discovery of several classes of such drugs, including NMDA receptor antagonists, N-type calcium channel blockers and a group identified initially as anticonvulsants that may act by multiple mechanisms. Animal models are now in wide use as a tool enabling researchers to screen such drugs and others. An alternative treatment for neuropathic pain has emerged with the development of gabapentin, a structural analogue of GABA, which has recently been shown to decrease the allodynia and hyperalgesia associated with animal model of neuropathic pain. Moreover, gabapentin has been shown to be effective in clinical conditions of neuropathic pain, which are resistant to standard analgesics. Similarly, an anti-arrythmic drug, mexiletine has been found effective in the treatment of painful diabetic neuropathy. The work can be expected to speed the arrival of effective therapies for patients who have had none.

PakMediNet -Pakistan's largest Database of Pakistani Medical Journals - http://www.pakmedinet.com