FDA Adverse Events — Free Drug Side Effect Reports API (No Key)

TL;DR

The FDA Adverse Events API provides access to the FAERS (FDA Adverse Event Reporting System) database, containing millions of reports of adverse drug reactions, medication errors, and therapeutic failures submitted to the FDA. You can query by drug name, reaction (side effect), patient demographics, and outcomes. Each report includes the drug(s) involved, the reactions experienced, patient age/gender, reporter type, and serious outcomes (hospitalization, death, disability). This data powers drug safety monitoring worldwide.

Quick start: https://api.fda.gov/drug/event.json?search=patient.drug.openfda.brand_name:ibuprofen&limit=1

No API key needed — just make a request!

How to Use This API

1. Search by Brand Name

https://api.fda.gov/drug/event.json?search=patient.drug.openfda.brand_name:ibuprofen&limit=3

2. Search by Reaction

https://api.fda.gov/drug/event.json?search=patient.reaction.reactionmeddrapt:headache&limit=5

3. Filter by Serious Outcome

https://api.fda.gov/drug/event.json?search=patient.drug.openfda.brand_name:aspirin&serious=1&limit=5

4. JavaScript — Recent Reports

fetch('https://api.fda.gov/drug/event.json?search=patient.drug.openfda.generic_name:metformin&limit=5')
  .then(r => r.json())
  .then(d => {
    d.results.forEach(r => {
      const reactions = r.patient.reaction.map(x => x.reactionmeddrapt);
      console.log(r.safetyreportid, '—', reactions.join(', '));
    });
  });

5. Python — Count Reactions for a Drug

import requests

# Count adverse events for ibuprofen
resp = requests.get('https://api.fda.gov/drug/event.json', params={
    'search': 'patient.drug.openfda.brand_name:ibuprofen',
    'count': 'patient.reaction.reactionmeddrapt.exact'
})
counts = resp.json()
for c in counts['results'][:10]:
    print(f"{c['term']}: {c['count']:,} reports")

Try it: https://api.fda.gov/drug/event.json?search=patient.drug.openfda.brand_name:ibuprofen&limit=2

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API Details

API URL: https://api.fda.gov/drug/event.json
Documentation: open.fda.gov/drug/event/
Category: Health
Authentication: Not Required
Geographic Coverage: USA (reports from US and worldwide)

Frequently Asked Questions

What is FAERS?: The FDA Adverse Event Reporting System is a database of adverse event reports, medication errors, and product quality complaints submitted to the FDA. It is the primary surveillance system for post-market drug safety.
How can I get reactions for a specific drug?: Use the count parameter: ?search=patient.drug.openfda.brand_name:DRUG&count=patient.reaction.reactionmeddrapt.exact to get a ranked list of reactions.
Can I search by patient demographics?: Yes, filter by patient.patientonsetage (age), patient.patientsex (1=male, 2=female), and patient.patientweight.
What outcomes are tracked?: Serious outcomes include death, life-threatening, hospitalization (initial/prolonged), disability, congenital anomaly, required intervention, and other serious outcomes.
How far back does the data go?: FAERS data is available from 1997 onwards, though electronic submissions became more comprehensive after 2010. The API covers the full historical archive.
What is a safety report ID?: Each report has a safetyreportid that uniquely identifies the submission. The same ID can be used to cross-reference reports across openFDA endpoints.

What You Can Build

Drug side effect browser for patient education
Pharmacovigilance dashboard tracking safety signals
Medication comparison tool comparing adverse event profiles
Clinical research data extraction tool
Patient safety alert system for high-risk drugs