The purpose of this study is to determine if analgesic efficacy can be detected with single dose administration in patients with chronic neuropathic pain due to painful diabetic neuropathy.

Inclusion Criteria:

• Patient has been treated for type 1 or 2 diabetes mellitus with glycosylated hemoglobin
• Patient has pain in both feet that occurred after onset of diabetes
• Patient agrees to maintain a consistent activity level throughout the study
• Patient is not on chronic pain therapy, or is on a stable dose of one pain therapy
• Female patients of reproductive potential must agree to use two acceptable methods of birth control through out the study
• Patients taking a pain medication must be on a stable dose at least 1 month prior to participating in study

Exclusion Criteria:

• Patient has a history of congestive heart failure
• Patient has/had a seizure disorder
• Patient has tried and failed 3 or more drugs to treat neuropathic pain
• Patient is currently taking pregabalin or duloxetine hydrochloride
• Patient has had a malignancy within the past 2 years (excluding basal cell carcinoma)
• Patient has history of hepatitis B or C or HIV infection
• Patient has skin-condition that may decrease sensitivity in area of neuropathic pain