Gabapentin Marches Toward Mechanism

Researchers are approaching a new level of understanding for the neuropathic pain-relief mechanisms of gabapentin. And the momentum generated by such a discovery may bring better tidings for the drug's difficult, if promising, history.

First approved by the US Food and Drug Administration (FDA) in 1993 as an add-on epilepsy treatment, the drug, marketed as Neurontin, led its manufacturer, Pfizer, into trouble. Pfizer, successor to the original maker, Warner-Lambert, agreed last year to pay $430 million to settle charges that Warner-Lambert had promoted the drug for various unapproved indications including restless leg syndrome, trigeminal neuralgia, and migraine. But meanwhile, gabapentin had become a blockbuster, as doctors had begun widely prescribing it for those same uses. Studies have since shown that use may be justified for at least one condition: shingles-associated neuropathic pain.¹ The FDA approved gabapentin for this in 2002.

But in a new setback, Pfizer lost a...