has part has role is deprotonated form of independent continuant antidepressant opioid analgesic antineoplastic agent adrenergic uptake inhibitor xenobiotic serotonergic antagonist muscarinic antagonist nicotinic antagonist organic molecular entity serotonin uptake inhibitor antitussive mu-opioid receptor agonist kappa-opioid receptor agonist NMDA receptor antagonist racemate delta-opioid receptor agonist anti-inflammatory agent capsaicin receptor antagonist vulnerary (R,R)-tramadol (S,S)-tramadol tramadol(1+) environmental contaminant tramadol CHEBI:9648 A racemate consisting of equal amounts of (<i>R</i>,<i>R</i>)- and (<i>S</i>,<i>S</i>)-tramadol. A centrally acting synthetic opioid analgesic, used (as the hydrochloride salt) to treat moderately severe pain. The (<i>R</i>,<i>R</i>)-enantiomer exhibits ten-fold higher analgesic potency than the (<i>S</i>,<i>S</i>)-enantiomer. Originally developed by Grünenthal GmbH and launched in 1977, it was subsequently isolated from the root bark of the South African tree <em>Nauclea latifolia</em>.