Nortilidine
Nortilidine is the major active metabolite of tilidine. It is formed from tilidine by demethylation in the liver. The racemate has opioid analgesic effects roughly equivalent in potency to that of morphine. The isomer has NMDA antagonist activity. The drug also acts as a dopamine reuptake inhibitor. The reversed-ester of nortilidine is also known which has almost identical properties to nortilidine.
