A group of doctors and public health officials urged the Food and Drug Administration on Wednesday to curtail the overuse and abuse of prescription painkillers by changing labeling directions on how and when physicians should prescribe them. The request came in a so-called citizens petition sent Wednesday to the F.D.A. by some 35 physicians, including Dr. Thomas A. Farley, the commissioner of the Department of Health in New York City, and Dr. Nirav R. Shah, the commissioner of the New York State Department of Health.