[Opioid-induced immunosuppression. A clinically relevant problem?]

Several in vitro and animal studies have demonstrated the immunosuppressive effects of opioids and an increased risk of infection. The clinical relevance of these findings is unclear. In this review the relevant animal and human studies on the relationship of opioid use and risk of infection are summarized. The areas of retroviral infections (i.e. human immunodeficiency virus, HIV), sepsis and pneumonia, postoperative and chronic pain therapy are covered. In the majority of animal studies an increased risk of infection was demonstrated but in human studies these findings were contradictory. However, these studies were frequently underpowered because they involved small patient collectives and do not reflect the standards of evidence-based medicine. In summary, a causal relationship between opioid therapy and an increased risk of infection could neither be conclusively demonstrated nor fully excluded.