title: Co-administration of opioid agonists and antagonists in addiction and pain medicine.
abstract: BACKGROUND
  mu-Opioid agonists have clinically useful effects and are used in a variety of acute and chronic pain conditions. However, repeated exposure to these drugs can lead to the development of physiologic dependence and, in some individuals, to opioid addiction.
  
  
  OBJECTIVE
  This review describes different rationales and modes of co-administration of opioid agonists and antagonists to increase and decrease the desired and undesired effects of the agonists.
  
  
  METHODS
  Publications in the English language were identified through a MEDLINE search and the bibliographies of identified articles were reviewed.
  
  
  CONCLUSIONS
  The clinical indication is a crucial determinant of how opioid agonists and antagonists are co-administered and, in turn, the selection of mode of co-administration (i.e., sequential or simultaneous) determines the most appropriate type of antagonist, dosage and route of administration. However, because each clinical application has both benefits and limitations, it is suggested that co-administration parameters need to be adjusted to the specific requirements of individual patients.
authors.affiliation: University of Guelph, Department of Psychology, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada. fleri@uoguelph.ca
authors.forename: Francesco
authors.initials: F
authors.lastname: Leri
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004333:Drug Administration Routes; D004359:Drug Therapy, Combination; D006801:Humans; D009292:Narcotic Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D009293:Opioid-Related Disorders / Q000517:prevention & control; D010146:Pain / Q000188:drug therapy*; D017450:Receptors, Opioid, mu / Q000819:agonists / Q000037:antagonists & inhibitors
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D017450:Receptors, Opioid, mu