Chiral Switches of Tramadol Hydrochloride, a Potential Psychedelic Drug-Past and Future.

The chiral opioid analgesic tramadol was patented (1962) as a cis - and trans -racemates mixture. A first chiral switch led to the (±)- cis -(1 RS ,2 RS ) racemate, patented and approved as Tramal (1980), preferred over the (+)- cis -(1 R ,2 R )-enantiomer. Consecutive chiral switches of (±)- cis -tramadol to (+)- cis -(1 R ,2 R )-tramadol/salts were patented. This Viewpoint calls for developing (+)- cis -(1 R ,2 R )-tramadol medicines and recognizing tramadol medicines as potential psychedelics to overcome the spreading tramadol crisis.