"Gabapentin is best known under the brand name Neurontin manufactured by Pfizer subsidiary Parke-Davis. In December 2004, FDA granted final approval to a generic equivalent to Neurontin made by Israeli firm Teva. Neurontin is one of Pfizer’s best selling drugs, and was one of the 50 most prescribed drugs in the United States in 2003. However, in recent years Pfizer has come under heavy criticism for its marketing of Neurontin, facing allegations that behind the scenes Parke-Davis marketed the drug for at least a dozen supposed uses for which the drug had not been FDA approved. By some estimates, so-called off-label prescriptions account for roughly 90% of Neurontin sales[1]. While off-label prescriptions are common for a number of drugs and are perfectly legal (if not always appropriate), marketing of off-label uses of a drug is strictly illegal. In 2004, Pfizer agreed to pay $430 million in fines for the illegal marketing of Neurontin for off-label purposes, and further legal action is pending. However, Pfizer maintains that the illegal activity originated in 1996, well before it accquired Parke-Davis (through its aquisition of Warner-Labmert) in 2000."
It supposedly potentiates benzos and opiates. It's also prescribed for tapering benzo withdrawal.
"What isn't Neurontin used for? It's the late-20th century's most successful snake oil!" (a derogatory term for medicines to imply that they are fake, fraudulent, and usually ineffective. The expression is also applied metaphorically to any product with exaggerated marketing but questionable or unverifiable quality)
"Monotherapy Treatment for Epilepsy (used all by its lonesome). Bipolar Disorder - basically useful only if bad anxiety or substance abuse is also present, or nothing else has worked. And then usually only as an add-on med. Migraines. Neuropathic pain. Depression. PTSD. Alcoholism (one study has it working well on mild-to-moderate alcohol withdrawal, another showed it to be insignificant for acute withdrawal). Anxiety (including panic and social phobia, but Parke-Davis' data are suspect, and public speaking). Sleep Disorders. Restless Leg Syndrome/PLMS, MS, Chronic Fatigue. Menopausal Symptoms. Treating HIV/AIDS-related Neuropathy. Phantom Limb Pain. Cocaine Abuse. And probably a bunch of stuff I don't even know about. Sometimes it's quite useful in these applications, sometimes it's prescribed first just because it's an anticonvulsant with a very low side effect profile and doctors are sick and tired of people whining about how medication sensitive they are."