The purpose of this study is to determine the best way to conduct clinical trials in patients with neuropathic pain (nerve pain). This study will see if generic pregabalin has any effect on neuropathic pain.

Inclusion Criteria:

• Patient has moderate to severe nerve pain due to one of the following conditions: Postherpetic neuralgia, Painful diabetic neuropathy, Small fiber neuropathy or idiopathic distal sensory polyneuropathy
• Patient is able to complete questionnaires in either English or Spanish
• Patient is at least 18 years of age

Exclusion Criteria:

• Patient is either pregnant or breastfeeding
• Patient has a history of angioedema (swelling beneath the skin surface) or peripheral edema (foot, leg, and/or ankle swelling)
• Patient has a history of congestive heart failure
• Patient has a seizure disorder
• Patient has a history of drug and/or alcohol abuse within the past 1 year
• Patient failed treatment due to lack of pain relief with more than three drugs for nerve pain
• Patient has had cancer (except basal cell carcinoma) within the past two years
• Patient anticipates the need for surgery while participating in the study
• Patient has a reported history of hepatitis B, C, or HIV infection
• Patient has another type of pain that is more painful than the nerve pain
• Patient has generalized anxiety disorder, untreated depression, psychosis, or post-traumatic stress disorder
• Patient is involved in litigation or receives worker's compensation related to nerve pain

The reported AEs were collected after patients were randomized to the double-blind withdrawal period of the study. AEs that were collected prior to randomization are not reported in this document.