Why does tramadol cause itching?

Jarales<br/>
is it because it releases Histamine, or because its activity on the Norepinephrine Receptors?<br/>
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Sierra<br/>
It has never caused itching for me and I have taken it for a long time. It does cause itching in many people. Atarax, which is suped up benadryl, will stop the itching and potentiate the medicine or in other words, boost the <i>Tramadol</i> abatement. see preceding verb add a sweet &quot;nod&quot; <br/>
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