[tramazoolla]

Tramadol is a synthetic stripped-down piperidine-analog of the phenantherane alkaloid codeine and, as such, is an opioid and also a pro-drug (codeine is metabolized to morphine, tramadol is converted to M-1 aka O-desmethyltramadol). Opioids are chemical compounds which act upon one or more of the human opiate receptors (the euphoria, addictive nature and respiratory depression are mainly caused by the Mu(?) 1 and 2 receptor. The opioid agonistic effect of Tramadol and its major metabolite(s) are almost exclusively mediated by the substance's action at the ?-opioid receptor. This characteristic distinguishes tramadol from many other substances (including morphine) of the opioid drug class, which generally do not possess tramadol's degree of subtype selectivity.