['postherpetic neuralgia', 'diabetic polyneuropathy', 'peripheral neuropathy']
['lidocaine hcl', 'normal saline']

        Inclusion Criteria:

          -  postherpetic neuralgia, diabetic polyneuropathy, peripheral neuropathy

          -  NRS score > 4

          -  stable oral medication during the 1 month trial period

          -  volunteers with informed consent

        Exclusion Criteria:

          -  pregnancy, breastfeeding, possibility of pregnancy

          -  pain from causes other than upper 3 indications

          -  hypersensitivity to lidocaine or other local anesthetics

          -  important disease of heart, kidney, liver or incurable disease that may affect the
             assessment of adverse effects, or may interfere with the completion of study

          -  severe conduction block

          -  history of other interventions that may affect the study

          -  Enrollment in other clinical trials within 30 days

          -  otherwise not suitable to study
      