Adverse Drug Reaction Classification System
Version 1.6
About ADReCS
An adverse drug reaction (ADR) is described by the World Health Organization (WHO) as a 'response to a medicine which is noxious and unintended, and which occurs at doses normally used in man.' Severe ADRs (SADRs) have caused significant clinical burden, and as well answer for a large portion of new drug development failure.
Adverse Drug Reaction Classification System (ADReCS) is a comprehensive ADR ontology database that provides both standardization and hierarchical classification of ADR terms. The ADReCS integrates ADR and drug information collected from public medical repositories like DailyMed, MedDRA, SIDER2, DrugBank, PubChem, UMLS, and so on. Unique ID of four digital combinations (xx.xx.xx.xxx) was designed and assigned to each standardized ADR term, corresponding to its position in a four level tree-like architecture.
What ADReCS can do ?

ADReCS will serve as a useful resource for aiding different aspects of toxicological studies, especially system toxicology and in silico drug safety evaluation. The ADReCS can be easily applied in the fields of:

  • Computational systems toxicology
  • Mechanism study of drug toxicity & Comparative drug safety evaluation
  • High throughput in silico drug safety evaluation & Drug design
  • Data mining of health information
  • Other computational toxicological applications
Related resources
MedDRA: Medical Dictionary for Regulatory Activities.
UMLS: Unified Medical Language System.
FDA: U.S. Food and Drug Administration.
DailyMed: Provides high quality information about marketed drugs.
DrugBank: Accessible resource of detailed drug data with comprehensive drug target information.
Database Statistics
System Organ Classes
High Level Group Terms
High Level Terms
Preferred Terms
All unique ADR terms
All ADR terms (include synonyms)
Drug-ADR pairs
News & Updates
UPDATE! Add 320 new drugs. The version 1.6 is ready for service.
UPDATE! Add 26 new drugs and 214 new ADR terms. The version 1.4 is ready for service.
The ADReCS manuscript is now online at Nucleic Acids Research!
The SMILES and structure search tools has been updated.
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