As we know that pain is the most common reason for which the patient takes medicine. Pain is not a single entity but
may be classified as nociceptive pain, inflammatory pain, and neuropathic pain. nociceptive pain such pain can be healed or
cured by using NSAIDs and other analgesics. Neuropathic pain is caused by the direct lesion on the neuron or damage or
dysfunction of peripheral or central neurons. Minor neuropathic can be healed automatically because peripheral nervous
systems neuron surrounded by Schwann cell which promotes the healing of neurons but CNS neurons don't have Schwann cell
they are covered with oligodendrocytes which don't have healing property so pain mediated through CNS are generally chronic
in nature. Even the smallest stimulation results in spontaneous intense pain after than it gets transformed into chronic pain
syndrome which is difficult to treat.IN chronic pain syndrome plastic changes occur in nociceptive neurons which cant be
reversed by pharmacological treatment. In this review
