Response to intravenous lidocaine infusion differs based on clinical diagnosis and site of nervous system injury.

We analyzed retrospectively pain relief from an intravenous lidocaine infusion (5 mg/kg/hr for 60 to 90 minutes) in 111 patients with chronic nonmalignant pain. Patients with peripheral nervous system (PNS) injury reported substantially more pain relief than those with central nervous system (CNS) injury or with pain of unknown etiology. These findings suggest that (1) the pathophysiology of chronic pain due to PNS injury is different from that due to CNS injury and idiopathic pain, and that (2) pain due to PNS damage may be suppressible by local anesthetic antiarrhythmic agents.