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. Despite these limited indications, gabapentin and pregabalin are widely prescribed off-label for various other pain syndromes. Such use is growing, possibly because clinicians are searching increasingly for alternatives to opioids.