<p>Tapentadol is a centrally-acting synthetic analgesic. It is 18 times less potent than morphine in terms of binding to human mu-opioid receptors. It also increases norepinephrine concentrations in the brains of rats via inhibition of norepinephrine reuptake. Selective mu-opioid antagonists like naloxone can block analgesia from tapentadol. It also has not effect on the QT interval.<br />
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Tapendadol causes large increases in levels of extracellular norepinephrine (NE) due to a dual mechanism of action involving mu opioid receptor (MOR) agonism as well as noradrenaline reuptake inhibition.</p>