Novel Opioid Analgesics and Side Effects

ACS Chem Neurosci. 2017 Aug 16;8(8):1638-1640. doi: 10.1021/acschemneuro.7b00195. Epub 2017 Jun 12.


Conventional opioids mediate analgesia as well as severe adverse effects via G-protein coupled opioid receptors (OR) in both inflamed (peripheral injured tissue) and healthy (brain, intestinal wall) environments. To exclude side effects, OR activation can be selectively achieved in damaged tissue by lowering the pKa of an opioid ligand to the acidic pH of inflammation. As a result, protonation of the ligand and consequent OR binding and activation of G-proteins is pH- and injury-specific. A novel compound (NFEPP) demonstrates the feasibility of this approach and displays blockade of pain transmission only at the peripheral site of injury, but with lack of central and gastrointestinal adverse effects. These findings suggest disease-specific receptor activation as a new strategy in drug design.

Keywords: Opioids; analgesia; inflammation; injury; opioid receptor.

MeSH terms

  • Analgesics, Opioid / adverse effects*
  • Analgesics, Opioid / pharmacology
  • Analgesics, Opioid / therapeutic use*
  • Animals
  • Drug Design
  • Humans
  • Receptors, Opioid / metabolism*


  • Analgesics, Opioid
  • Receptors, Opioid