The purpose of this study is to determine whether dextromethorphan (Neurodex) and quinidine are effective in the treatment of pain of diabetic neuropathy.

Inclusion Criteria:

• Diagnosis of diabetes mellitus
• Established diabetic therapy for at least 3 months
• Lab-supported diagnosis of painful diabetic distal symmetric sensory/motor polyneuropathy
• Pain the previous three months
• Not pregnant

Exclusion Criteria:

• Patient failed adequate trial of 3 or more medications or has required narcotics for pain
• History of torsades de pointes
• Sensitivity to quinidine or opiate drugs (codeine, etc)
• Severe pain that could confound the assessment
• Patient has had any amputations
• Patient has participated in the past 30 days or is currently participating in another trial
• Patient has previously received treatment with dextromethorphan and quinidine