Tolerability of Three Local Anesthetic Formulations in Conjunction With NGX-4010 for the Treatment of Neuropathic Pain

Key Eligibility Criteria: Must have had for at least 3 months painful diabetic neuropathy, or postherpetic neuralgia, or painful HIV-associated neuropathy, with moderate to severe pain on average. Must not have significant pain due to other causes (for example, arthritis). Must have intact skin at the treatment area. Must be prepared to remain on the same pain medications at the same doses as before the study for the entire duration of the study (12 weeks). Must not use topical pain medications on painful areas. Must be able to comply with study requirements such as completing daily pain diary and attending study visits and refrain from extensive travel during study participation. Must be at least 18 years old, not pregnant, and able to take care of self independently, with only occasional assistance if needed. No significant medical problems of the heart, kidneys, liver or lungs, or cancer. No history or current problem with substance abuse.