title: Opioids and the immune system: clinical relevance.
abstract: OBJECTIVE
  The increasing use of opioids for pain treatment is a reality in several countries and, therefore, unusual questions arise, such as the influence of opioids on immune responses. The present study aims to detail the immune response by exploring the influences of opiate effects on inflammatory response in experimental and clinical situations, as well as its importance in daily practice.
  
  
  BACKGROUND
  After reviewing the articles published in journals indexed in Medline, we found that immune response has been generally described, especially regarding its cellular aspect. Following this approach, we identified the mechanisms of endogenous opioid release, modulation of immune response to exogenous opioids in acute and chronic pain, always ending with the clinical implications and applicability in routine care.
  
  
  CONCLUSIONS
  Although several studies point to an immunosuppressive effect of opioids, the clinical relevance of these observations remains uncertain and only serves as a prerequisite for further investigations in this area. Definitive recommendations for the use of opioids in various situations of clinical practice regarding the immunological consequences of these drugs still cannot be provided until the present moment.
authors.affiliation: Department of Anesthesiology, Pain and Palliative Care, Universidade Federal do Maranhão. jbgarcia@uol.com.br
authors.forename: João Batista Santos
authors.initials: JB
authors.lastname: Garcia
authors.forename: Mirlane Guimarães de Melo
authors.initials: MG
authors.lastname: Cardoso
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Dos-Santos
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D006801:Humans; D007107:Immune System / Q000187:drug effects*; D018847:Opioid Peptides / Q000502:physiology
chemical_list: D000701:Analgesics, Opioid; D018847:Opioid Peptides