http://whqlibdoc.who.int/hq/1999/WHO_EDM_QSM_99.6.pdf

It lists common stems for which chemical and/or pharmacological categories have been established. These stems and their definitions have been selected by the INN experts and are for use when selecting new internationalnonproprietary names for pharmaceutical substances that belong to an established series of related compounds. Document in pdf format; Acrobat Reader required.