http://www.dextromethorphanhydrobromide.org/ (http://www.dextromethorphanhydrobromide.org/)
Patent GB822055 (http://l2.espacenet.com/dips/viewer?PN=GB822055&CY=gb&LG=en&DB=EPD)
it seems like you end up with a patent for the manufacture of cricket and hockey balls... ;Dhttp://l2.espacenet.com/espacenet/bnsviewer?CY=gb&LG=en&DB=EPD&PN=GB822055&ID=GB++++822055A++I+ (http://l2.espacenet.com/espacenet/bnsviewer?CY=gb&LG=en&DB=EPD&PN=GB822055&ID=GB++++822055A++I+)
alleged to be three times more euphoric than heroin at equianalgesic doses...
Dependence liability is similar to morphine, but with a less severe withdrawal syndrome....
...fast onset of action when taken orally, and has a high bioavailability which means that oral dosing produces almost as much effect as injection. It also has a relatively low tendency to cause constipation...
...tolerance to the analgesic effects develops relatively slowly