Pfizer Inc. (PFE) (PFE)’s second-best selling drug, Lyrica, was approved by U.S. regulators today for use against pain caused by spinal cord injuries. The Food and Drug Administration cleared the expanded use of Lyrica, already backed to treat nerve pain from fibromyalgia, diabetic nerve pain and pain after shingles, New York-based Pfizer, said today in a statement. Pfizer estimates a potential patient population size of about 100,000 people. “Until now, no FDA approved treatment options were available in the U.S. for people with neuropathic pain associated with spinal cord injury, a condition which can be extremely disabling,” said Steven J. Romano, senior vice president and head of Pfizer’s medicines development group, Global Primary Care business unit.