About PillSignal

PillSignal is a free tool for exploring adverse event data reported to the U.S. Food and Drug Administration. It is designed for patients, caregivers, and anyone who wants to understand what events have been reported in association with prescription medications.

Where the data comes from

The data on PillSignal is sourced from the FDA Adverse Event Reporting System (FAERS), a public database maintained by the FDA. We access this data through the OpenFDA API, which provides programmatic access to FAERS records. The FAERS database is updated quarterly.

What is FAERS?

FAERS is a voluntary reporting system. Patients, healthcare providers, pharmacists, and drug manufacturers can submit adverse event reports to the FDA when they observe a reaction that may be associated with a medication. Submission does not require proof that the medication caused the event — only that the reporter suspects a possible connection.

Because reporting is voluntary and unverified, FAERS data has important limitations. PillSignal surfaces these limitations on every page so users can interpret the data appropriately.

Important context for interpreting this data

• Reports do not prove causation. An adverse event appearing in FAERS alongside a drug name means someone reported those two things together — not that the drug caused the event.
• Data may include duplicates. The same event can be submitted multiple times by the patient, their prescriber, and the drug manufacturer. FAERS does not always deduplicate these.
• Report volume reflects prescribing volume. A drug with tens of thousands of reports may simply be one of the most widely prescribed medications in the country. More reports does not mean more risk.
• Underreporting is common. Because reporting is voluntary, the absence of reports for a drug does not indicate that it is safe or free of adverse events.
• Data may contain errors. Reports are submitted by humans and may include incomplete, inaccurate, or misattributed information.

What PillSignal is not

Not medical advice. Nothing on PillSignal should be used to make healthcare decisions. If you have questions or concerns about your medications, consult your healthcare provider.

Not affiliated with the FDA. PillSignal accesses public data made available through the OpenFDA API but is an independent project with no affiliation with the U.S. Food and Drug Administration.

Not a diagnostic tool. The data presented reflects voluntary reports submitted by individuals. It cannot be used to determine whether a medication is safe or effective for any individual.

Questions or feedback?

Reach us at [email protected].