Vitamin Information Center

Adverse Events
Definition
An adverse event (AE) is any adverse change in health
or “side-effect” that occurs in a person during a clinical
trial or within a pre-specified period after dosing of
a drug is complete. Not every adverse event is causally
related to the treatment being studied, but researchers
must report all adverse events to the relevant regulatory
authority in the country where the drug is to
be registered. Adverse events categorized as “serious”
(for example death, illness requiring hospitalization,
events deemed life-threatening, etc.) must be reported
to the regulatory authorities immediately, whereas
minor adverse events are merely documented in the
annual summary sent to the regulatory authority.
Cross-References
 Adverse Drug Reaction
 Adverse Effect
 Side Effect

Adverse Effect
Synonyms
Adverse events; Adverse outcome; Complication; Side
effects
Definition
Adverse effects are harmful and undesired effects
resulting from either medication or interventions like
chemotherapy or surgery. Adverse effects that result
from medication are called  side effects when those
effects are secondary to the main or therapeutic effect
of the drug, sometimes due to unsuitable or incorrect
dosage or procedure. Adverse effects from medical procedures
may occur in the course of surgery, like infection,
hemorrhage, inflammation, scarring, loss of function,
or changes in local blood flow. Non-surgical procedures
like high intensity radiotherapy might result in
burned skin, for example. Adverse effects can cause
reversible or irreversible changes.
Cross-References
 Adverse Drug Reaction
 Side Effect

Adverse Drug Reaction
Synonyms
Side effect; Adverse effect; Adverse events
Definition
An adverse drug reaction (abbreviated ADR) is a term
to describe the unwanted, negative consequences sometimes
associated with the use of different medications.
It includes a wide range of outcomes that can be toxic,physical or psychological reactions to a drug. The reaction
may be allergic, predictable or unpredictable. The
scientific discipline that focuses on the study of ADRs
is pharmacovigilance.
Cross-References
 Side Effect