%0 journal article
%@ 0066-4219
%A Stein, C.

%D 2016
%J Annual Review of Medicine

%P 433-451 
%R doi:10.1146/annurev-med-062613-093100
%T Opioid Receptors
%U https://doi.org/10.1146/annurev-med-062613-093100
 
%X Opioids are the oldest and most potent drugs for the treatment of severe pain. Their clinical application is undisputed in acute (e.g., postoperative) and cancer pain, but their long-term use in chronic pain has met increasing scrutiny. This article reviews mechanisms underlying opioid analgesia and other opioid actions. It discusses the structure, function, and plasticity of opioid receptors; the central and peripheral sites of analgesic actions and side effects; endogenous and exogenous opioid receptor ligands; and conventional and novel opioid compounds. Challenging clinical situations, such as the tension between chronic pain and addiction, are also illustrated.