Immunomodulatory effects of opioids.

Immunomodulatory effects of opioids
Adesola Odunayo, DVM, MS; John R. Dodam, DVM, MS, PhD, DACVA;
Marie E. Kerl, DVM, DACVIM, DACVECC and Amy E. DeClue, DVM, MS, DACVIM
Abstract
Objective – To review the immunomodulatory effects of opioids.
Data Sources – Original research publications and review articles using the PubMed search engine with the
following keywords – opioids, morphine, immuomodulation, and immunosuppression.
Veterinary and Human Data Synthesis – Opioids have been shown to modulate the immune system in
animal models by affecting both the acquired and innate arms of the immune system. Natural killer cell
activity, T-cell proliferation, antibody production, phagocytic cell function, and cytokine production have all
been shown to be affected by opioids. Many of these effects are reversed by opioid antagonists. Opioids have
also been shown to induce sepsis in laboratory animals. Opioid administration alters immune parameters in
healthy humans at analgesic doses and may increase the risk of infection in some patient populations.
Conclusions – While opioids remain the most powerful and widely used analgesics available, their negative
effects on the immune system are well established in the laboratory setting. Thoughtful consideration should
be given to the use