Alpha2-agonists as analgesic agents

Med Res Rev. 2009 Mar;29(2):339-68. doi: 10.1002/med.20134.


It is well known that norepinephrine is involved in the control of pain by modulating pain-related responses through various pathways. alpha(2)-Adrenergic agonists have a well-established analgesic profile and, in the recent years, have found a wider application, in particular as adjunct to anesthetics and analgesics in perioperative settings. This review analyzes the alpha(2)-agonists currently in clinical use, starting from the prototype Clonidine, as well as the most promising and studied molecules. In addition, an overview of the imidazoles, imidazolines, and hydroxyethyl-thioureas derivatives published in both the open and patented literature is presented, providing chemical description and pharmacological data. Finally, the most commonly alpha(2)-agonists used in veterinary medicine are described.

Publication types

  • Review

MeSH terms

  • Adrenergic alpha-2 Receptor Agonists*
  • Analgesics / chemistry
  • Analgesics / pharmacology*
  • Animals
  • Clonidine / chemistry
  • Clonidine / pharmacology
  • Humans
  • Pain / drug therapy


  • Adrenergic alpha-2 Receptor Agonists
  • Analgesics
  • Clonidine