Morphine's immunoregulatory actions are not shared by fentanyl.

Fentanyl is a commonly used narcotic agent in anesthesia. It has strong analgesic properties which it shares with morphine. Unlike morphine, it does not possess the ability to bind to the mu3 receptor, and therefore does not have the ability to influence nitric oxide release as measured amperometrically. Cell adhesion also is not influenced. As a result, it also lacks the ability to downregulate the inflammatory response associated with surgery, especially cardiopulmonary bypass.