are matched to fifth level ATC codes where applicable. Formats WHODrug is offered in Four formats (called B3 and C3). B3 format is brief while C3 format contains additional columns on top of B3 format. Dictionary Versions Standardised Drug Groupings WHODrug concepts can be organized into groups. Standardised Drug Groupings (SDGs) define groups of drugs. For example, diuretics, corticosteroids, drugs used in diabetes. Groups are also defined based on interaction, for example, drugs interacting with CYP2C8 or drugs interacting with UGT. References External links www.who-umc.org Pharmacological classification systems