The gabapentinoid drugs gabapentin and pregabalin were originally developed as antiseizure drugs but now are prescribed mainly for treatment of pain. For gabapentin, the only pain-related indication approved by the US Food and Drug Administration (FDA) is postherpetic neuralgia. For pregabalin, FDA-approved indications related to pain are limited to postherpetic neuralgia, neuropathic pain associated with diabetic neuropathy or spinal cord injury, and fibromyalgia.