Histamine release induced by opioid analgesics: a comparative study using porcine mast cells.

Studies in vitro have demonstrated histamine release induced by opioid analgesics from rat peritoneal mast cells and human skin mast cells. In humans, elevated plasma histamine levels have also been found following intravenous or oral administration. This study compared the reactivity of five opioid analgesics on mast cell suspensions obtained from porcine heart, kidneys, liver and lungs. The five compounds investigated were hydromorphone, levomethadone, morphine, pethidine and oxycodone. Both morphine and hydromorphone produced little histamine release from all cell types tested. The other drugs demonstrated clear differences between the different cell populations. Thus, the cardiac cells responded most strongly to oxycodone but were the least responsive to pethidine. These differences, if confirmed in vivo, could indicate which drugs may be more suitable for patients with different underlying disease states.