Immune responses in fatalities involving opioids.

In some cases of fatalities involving opioid use, the concentrations of detected opioids are not in the toxic range. Immune reactions can be triggered by opioid use, suggesting that immune response may be a factor in these cases. Autopsy cases from 2002-2012 were reviewed. Persons with physical, microscopic or serum evidence of allergic reactions and opioid use at autopsy were compared to persons who used opioids but had no such signs. Overall, 49 persons were identified who had used opioids, of which five had evidence of immune response. A medical history of asthma was significantly more common in persons with signs of immune response (P = 0.0244) and fatality (P = 0.0085) compared to normals. A history of asthma is suggestive of susceptibility to immunologic reactions to opioids, and correlates strongly with the cause of death.