NLM-DDI CD corpus

DailyMed Cardiovascular Product Labels Annotated

with Drug-drug Interactions

developed by the National Library of Medicine

180 annotated DailyMed product labels with drug-drug interactions.

Drug-Drug Interaction Annotation schema


1.       Entities

1.       Drug Class

Drug classes are assigned based on different characteristics: chemical ingredients, administration method, mechanism of action, and the target organ or target anatomical system. Any of these categories is a drug class and can include one or many individual drugs or substances.

2.       Drug

A drug is a chemical substance administered for medicinal purposes. Drug names can be generic (chemical name of the substance) or brand names.

3.       Substance

Substances refer to any material entities that are not drug or drug classes. These include foods, nutritional supplements and other things that can be found in the environment.

4.       Span

Span refers to a span of text that:

*provides information about an interaction (context for interaction, severity of interaction, strength of evidence)

*is a fragment of text associated with an entity

*is an antecedent to an anaphor that refers to an event


An expression is a span of text containing an anaphor. The anaphora may refer to an entity or an event represented by a span.


2.     Relations

1.       Drug class member relationships

Drugs are linked to classes with a hasDrugMember relation. Drug classes are linked to parent classes with a hasClassMember relation. Substances are linked to classes with a hasSubstanceMember relation.

2.       Anaphora relationships

Expressions containing an anaphora are linked to their antecedent with a Coreference relation. The antecedent must be an entity (drug, drug class, substance, Span, or Expression).

3.       Fragment relationships

Fragmented parts of an entity are connected by the hasFragment relation.


3.     Drug Interaction Events

Interactions are biochemical or physiological changes on the human body caused by the concomitant action of two or more chemical components. Interactions can occur between drug classes, drugs, and substances. Interactions should not be confused with side effects or drug actions.

Caution Interaction

Caution interactions are general precautions about the use of two entities together without specific mention of an effect.

Increase Interaction

Increase interactions indicate higher levels or increased effects of the object drug in the system as a result of the precipitant drug.

Decrease Interaction

Decrease interactions indicate lower levels or decreased effects of the object drug in the system as a result of the precipitant drug.

Specific Interaction

Specific interactions indicate specific effects resulting from the interaction.

All drug interaction event types contain the Interaction Indicator as well as entities in the following roles:

Object of interaction (mandatory)

The object of interaction is a drug class, drug or a substance whose effect is altered by the precipitating entity. The object entity is linked to the interaction indicator with a hasObject-Argument relation.Precipitant of interaction (mandatory)

The precipitant of interaction is a drug class, drug, or substance that alters the pharmacological and/or other action of the object entity. The precipitant entity is linked to the interaction indicator with a hasPrecipitant-Argument relation.

Context for Interaction (optional)

The context is a population characteristic or event for which the drug interaction was observed. Context is a property of the interaction and qualifies the patient, not the drug. The Context for Interaction Span is linked to the interaction indicator with a hasContext-Argument relation.

Strength of Evidence (optional)

The strength refers to the scientific research evidence for the interaction. The Strength of Evidence Span is linked to the interaction indicator with a hasStrength-Argument relation.

Severity of Interaction (optional)

The severity is reserved for contraindicated interactions. The Severity of Interaction Span is linked to the interaction indicator with a hasSeverity-Argument relation.


Drug-drug Interactions are encoded with the same XML schema as the SemEval Task 9 DDI DrugBank and DailyMed corpora.

A drug interaction is encoded in the following way:

Sentence containing the DDI

Annotated entities within the sentence with a corresponding normalization if available

List of annotated relations

List of interacting drug pairs within the sentence and attributes of the interaction

The complete annotation guidelines are available here.

The corpus is available for download here.

Corpus in Original format (produced by the Brat Annotation Tool -

The corpus with the original annotations can be downloaded here.


Johann Stan,

Olivier Bodenreider,