(healthday) If you arrive in an emergency room in significant pain, you are less likely to be prescribed a narcotic to ease that pain if you are not white, new research shows. The reasons for the disparity aren't clear, but there's no doubt that minorities don't get effective pain treatment in the ER as often as whites do, said study author Dr. Mark Pletcher, an assistant professor of epidemiology and biostatistics at the University of California, San Francisco. "There's no difference in the pain severity or types of pain that people are presenting with, but the difference is there consistently." To come to this conclusion, Pletcher and his colleagues examined reports from a national survey about visits to emergency rooms between 1993 and 2005. Pain-related visits made up 156,729, or 42 percent, of 374,891 visits tracked by the survey. Researchers did find that doctors have started prescribing powerful painkillers -- including morphine, codeine, oxycodone and Vicodin -- more often in recent years. Thirty-seven percent of pain-related cases were treated with narcotics in 2005, a jump from 23 percent in 1993. The overall use of opioid drugs may have grown because, as the study noted, doctors began paying more attention to poorly treated pain during the 1990s. But that increased attention appears to have been tempered by the race of the patient. White patients received opioid drugs 31 percent of the time, compared to lower rates among blacks (23 percent), Hispanic (24 percent), and other groups such as Asians (28 percent). In 2005, whites received the drugs 40 percent of the time, while all others got them 32 percent of the time.