Adverse Drug Event (ADE)

Key facts

Postmarketing reporting rules

21 CFR 314.80 (drugs) and 21 CFR 600.80 (biologics)

Expedited reports

Serious and unexpected events, within 15 calendar days

Voluntary reporting channel

MedWatch, for health professionals and consumers

Diagnosis coding

ICD-10-CM T36-T50: poisoning, adverse effect and underdosing of drugs

What is an adverse drug event?

An adverse drug event covers harm linked to taking a drug, whether or not the drug was used correctly. It includes adverse drug reactions from appropriate use, allergic reactions, harm from medication errors such as a wrong dose or wrong drug, overdoses, and harm from interactions.

The terms vary by setting. Food and Drug Administration (FDA) postmarketing rules use "adverse drug experience" for any adverse event associated with use of a drug, whether or not it is considered drug related. Patient safety programs use adverse drug event for harm to patients. Adverse drug reaction usually implies at least a reasonable possibility that the drug caused the event.

FDA regulations treat an event as serious when it results in death, is life-threatening, requires or prolongs inpatient hospitalization, causes persistent or significant disability, causes a congenital anomaly, or is an important medical event that may require intervention to prevent one of those outcomes.

How adverse drug events are reported

ADE information reaches regulators and researchers through several channels:

• Application holders must report adverse experiences they learn about to FDA. Serious and unexpected events go in expedited 15-day reports; others go in periodic reports, quarterly for the first 3 years after approval and annually after that.
• Health care professionals, patients and caregivers can report voluntarily through MedWatch.
• Drug and therapeutic biologic reports are stored in the FDA Adverse Event Reporting System (FAERS). Vaccine events go to the Vaccine Adverse Event Reporting System (VAERS), and device events go to the MAUDE database.
• Safety reporting during clinical trials under an investigational new drug application follows separate rules in 21 CFR 312.32.
• Hospitals capture ADEs in internal incident reports and in ICD-10-CM diagnosis codes on claims.

Why adverse drug events matter

ADEs connect drug safety to cost, quality and competition:

• Pharmacovigilance teams screen spontaneous reports, literature and real-world data for new ADE signals that may lead to label changes.
• Health systems and payers track ADEs as a patient safety and cost measure; federal prevention efforts have focused on anticoagulants, diabetes medicines that can cause hypoglycemia, and opioids.
• Medical affairs and commercial teams compare adverse reaction profiles in labeling across competitors, since tolerability affects adherence and positioning.
• Claims analysts can find ADE-related emergency visits and admissions through ICD-10-CM adverse effect codes, although coded data undercounts events.