"Undertreatment of pain among African Americans has been well documented. For example, children with sickle-cell anemia (a painful disease that occurs most often among African Americans) who presented to hospital emergency departments (EDs) with pain were far less likely to have their pain assessed than were children with long-bone fractures (Zempsky et al., 2011).
"In general, moreover, a number of studies have shown that physicians tend to prescribe less analgesic medication for African Americans than for whites (Bernabei et al., 1998; Edwards et al., 2001; Green and Hart-Johnson, 2010). A study that used a pain management index to evaluate pain control found that blacks were less likely than whites to obtain prescriptions for adequate pain relief, based on reported pain severity and the strength of analgesics provided. Because such an index is a way to quantify a person’s response to pain medication alone, it is likely that people in this study did not receive other types of treatment for pain either."

Source

Institute of Medicine, "Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research" (Washington, DC: National Academy of Sciences, 2011), p. 68.
http://www.nap.edu/openbook.p…