Drug-Drug Similarity

1. ATC Code
   

   The Anatomical Therapeutic Chemical (ATC) Classification System is used for the classification of active ingredients of drugs according to the organ or system on which they act and their therapeutic, pharmacological and chemical properties. It is controlled by the World Health Organization Collaborating Centre for Drug Statistics Methodology (WHOCC), and was first published in 1976.ATC code can be obtained from DrugBank database.

2. Chemical Structure
   

   The chemical structure is a category that reflects the order of the atoms of each element inside the material molecule, that is, the way in which the atoms are connected and the order, and is the basis for understanding and mastering the chemical properties of the substance and the laws of chemical reaction. The chemical structure of the drug affects the molecular activity of the drug

3. Side Effects
   

   Drug side effects refers to pharmacological effects other than the therapeutic purpose that occurs after a therapeutic amount of a drug is applied.The database Sider saves side effect information

4. Drug-Targets
   

   Drug targets refer to biological macromolecules, such as some proteins and nucleic acids, which have pharmacodynamic functions in vivo and can be acted by drugs. Genes that encode target proteins are also known as target genes. Pre-determination of target molecules related to specific diseases is the basis of modern drug development.

   Targets contain sequence, protein-protein interaction, gene ontology and so on.

5. Drug-Drug Interaction
   

   Drug-Drug interaction refers to the combined effects of two or more drugs taken by patients at the same time or in a certain period of time, which can enhance the efficacy or alleviate the side effects, weaken the efficacy or produce undesirable side effects. Enhanced effects include increased efficacy and increased toxicity, while weakened effects include reduced efficacy and toxicity. Therefore, in the clinical use of combined drugs, we should pay attention to the use of the characteristics of various drugs, give full play to the pharmacological role of each drug in the combined drugs, in order to achieve the best curative effect and minimize adverse drug reactions, so as to improve the safety of drug use.

Disease-Disease Similarity

1. Disease-gene association
   

   Disease prevention can be carried out through the relationship between diseases and genes, and genetic information can reflect disease information to some extent. The similarity between diseases can be calculated by the relationship between disease-genes and gene ontology information.

2. Disease ontology
   

   Disease Ontology (DO) is the official ontology of human disease.The Ontology Project is hosted by the Institute of Genomics at the University of Maryland School of Medicine.
   Originally developed at Northwestern University in 2003, the Ontology Project aims to meet the needs of specific building ontology that covers all the disease concepts annotated in the biomedical resource pool within an ontological framework that can be extended to meet community needs.
   Disease ontology is an OBO (Open Biomedical Ontology) foundry ontology.
   The disease ontology identifier (DOID) consists of the prefix DOID: followed by a number, for example, Alzheimer's disease has a stable identifier DOID: 10652

3. Phenotype
   

   The phenotype can be any observable characteristic or trait of the disease, such as morphological, developmental, biochemical or physiological properties or behavior, without any suggestion of a mechanism. The clinical phenotype will be the manifestation of the disease in a given individual