Lyrica 300 mg (Pregabalin) is used to relieve the nerve pain caused by a variety of illnesses as well as to treat partial-onset seizures. Pregabalin alters the way nerves convey messages to the brain.This medicine alleviates pain caused by diabetic nerve damage, shingles (herpes zoster) infection, or spinal cord injury. This medicine is also used to relieve pain in fibromyalgia patients. Pfizer's brand name for the medicine pregabalin is Lyrica.