1. Substance Hierarchy Therapeutic Role cleanup 25 August 2015 Romin Khazai, Senior Terminologist

2. Current status Substance Hierarchy currently contains about 300 concepts which are therapeutic role related acting as groupers for 7000 substances.

3. Grouper concepts Current types of grouper concepts in the Substance Hierarchy: ▪Therapeutic (Role): ▪These are characterised by the therapeutic intent of the product containing the substance. These are planned to be retired as the assertions are not always true about the substance. ▪Examples: antidiabetic agent, skin agent, cardiovascular agent ▪Mechanism of Action (Disposition) ▪These concepts are related to the way the children concepts interact with the human body or their mechanism of action. These can also include substances which refer to the biological nature or site of action of the substance. ▪Examples: non-selective beta-blocking agent, angiotensin converting enzyme inhibitor agent ▪Chemical, Functional group ▪These concepts are related to the main features of the chemical composition of the substance. These are always true about a substance in every setting. These are based on either the general chemical composition of the substance or the largest chemical functional group in the chemical structure. ▪Example: amide, pyrimidine, alpha amino acid

4. Affected concepts in related hierarchies A number of concepts in related hierarchies use the substance concepts to define their groupers. For example: Adverse reaction to drug (disorder) Poisoning by drug AND/OR medicinal substance (disorder) Drug allergy (disorder) In this example, the Causative agent will be retired and the concept made primitive. This will allow the therapeutic role substance to be retired

5. Affected concepts in related hierarchies

6. Inferences Retiring the causative agent attribute and making the grouper concept primitive will cause the concept to lose inferring children. However, as seen in this example, there is a large number of incorrect inferences

7. Stated relationships After losing the inferred descendants, only the stated descendants will remain.

8. Other examples Timolol is not always used as a ‘eye drug’, and is not appropriately being inferred, along with these substances.

9. Other examples Aluminum hydroxide is not always used as a ‘gastrointestinal system drug’, and is not appropriately being inferred.

10. Other examples Only stated relationships remain

11. Other examples Chlorhexidine allergy (disorder) will no longer infer after the change Sodium hyaluronate allergy (disorder) will no longer infer after the change