Definition · Plain-language
Adverse event reporting
Adverse event reporting is the systematic documentation and submission of untoward medical occurrences experienced by patients or clinical-trial subjects, forming the raw material of pharmacovigilance.
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What an adverse event is
An adverse event is any untoward medical occurrence in a patient or clinical-trial subject who has been administered a medicinal product, whether or not it is considered related to that product. This deliberately broad definition means an event is captured on the basis of its occurrence in time, not on a prior judgement that the medicine caused it. Causality assessment is a separate analytical step. The breadth ensures that potentially important safety information is not filtered out prematurely by assumptions about cause.
Spontaneous and solicited reporting
Reports arise in two main ways. Spontaneous reports are unsolicited communications, typically from healthcare professionals or patients, describing an event suspected to be associated with a medicine in routine clinical use — the basis of post-marketing surveillance. Solicited reports come from organised data-collection settings such as clinical trials, registries or patient-support programmes, where information is actively sought. Within trials, investigators document adverse events systematically, and serious events trigger expedited reporting obligations to sponsors and regulators.
Why reporting matters
Adverse event reporting is the foundation on which pharmacovigilance is built. Aggregated case reports feed national and international databases such as FAERS and EudraVigilance, where they can be analysed for safety signals. Because rare or delayed reactions may not appear in pre-approval trials, ongoing reporting once a product is widely used is essential to detecting them. Each individual report records a suspicion or an observation; conclusions about safety emerge only from careful evaluation of the accumulated evidence.
Key facts
At a glance
- Definition: Documenting and submitting untoward medical occurrences in patients/subjects.
- Underpins: Pharmacovigilance and drug-safety surveillance.
- Types: Spontaneous (unsolicited) and solicited (e.g. within trials).
- Data unit: Individual case safety report (ICSR).
- Key point: An adverse event is recorded regardless of presumed causation.
- Feeds: Databases such as FAERS and EudraVigilance.
Common misconceptions
What people often get wrong
Often heard: An adverse event is by definition caused by the medicine.
Actually: An adverse event is any untoward medical occurrence after administration, whether or not related to the product. Causality is assessed separately and is not assumed by the act of reporting.
Often heard: Only serious events need to be reported.
Actually: Many adverse events are recorded, not only serious ones. Seriousness affects which expedited reporting timelines apply, but non-serious events are still documented within pharmacovigilance systems.
Often heard: Reporting an adverse event means the reporter is certain the drug is to blame.
Actually: A report reflects a suspicion or an observation, not a confirmed conclusion. The purpose is to capture information for later evaluation, not to assert proven cause.
Going deeper
