Structural comparisons of meptazinol with opioid analgesics.

Aim: To investigate the mechanism of action of a potent analgesic, (+/-)-meptazinol.

Methods: The structures of meptazinol enantiomers were compared with opioid pharmacophore and tramadol.

Results: Neither enantiomer of meptazinol fitted any patterns among the opioid pharmacophore and tramadol, although they did share some structural and pharmacological similarities.