After each quiz answer, you'll see a number like "1,302 reports" mentioning that side effect. Those numbers come from the FDA Adverse Event Reporting System, or FAERS, a database of reports about problems people had while taking a medicine. It's a valuable safety tool, but the numbers are easy to misread.
Where the reports come from
Drug makers are required to send the FDA the reports they receive. Doctors, pharmacists, patients and caregivers can report too, voluntarily. The FDA uses the database to look for warning signs, such as a side effect turning up much more often than expected, which can lead to new label warnings.
What the numbers can't tell you
- A report isn't proof. It means someone noticed a problem while taking the drug. The drug may not have caused it.
- They aren't rates. FAERS doesn't know how many people took a drug, so a count can't tell you how likely a side effect is. A widely used drug will have more reports simply because more people take it.
- Most problems are never reported. Reporting is voluntary for patients and health professionals, so the database captures only a fraction of what happens.
- Some reports are duplicates or incomplete. The same event may be reported by both a patient and a doctor, for example.
- News can drive reports. Publicity about a side effect can lead to more reports about it.
Why the quiz shows them anyway
The counts show that these side effects aren't just words on a page; real people have reported them. When a count is large, it often reflects how widely a drug is used. When it's small, the effect may be rare, or simply not the kind of thing people report. For how likely a side effect really is, the label's clinical trial data is the better guide. See why labels list so many side effects.
Anyone can search the reports through the FDA's FAERS Public Dashboard or openFDA. Each quiz answer includes a "See the query" link that shows exactly how its number was counted.
Sources
This article is general information, not medical advice. Talk to your doctor or pharmacist about your own medicines.