Analogs
Circa 1999, the Government of Spain proposed amending Schedules I and II to include isomers, esters, ethers, salts of isomers, esters and ethers, and any "substance resulting from modification of the chemical structure of a substance already in Schedule I or II and which produced pharmacological effects similar to those produced by the original substances". The WHO opposed this change. The Commission on Narcotic Drugs did amend the Schedules to include stereoisomers, however, with the understanding that "specific isomers that did not have hazardous pharmacological activity and that posed no danger to society could be excluded from control, as dextromethorphan had been in the case of Schedule I of the 1961 Convention."
Read more about this topic: Convention On Psychotropic Substances