FAERS: The Hidden System That Tracks Dangerous Drug Side Effects

When you take a medication, you rely on clinical trials to tell you what might go wrong. But those trials only involve a few thousand people for a few months. What happens when millions start using the drug for years? That’s where FAERS, the FDA’s Adverse Event Reporting System. Also known as FDA Adverse Event Reporting System, it collects real-world reports of side effects, hospitalizations, and deaths linked to medications. This isn’t theoretical—it’s the most detailed public record of what actually happens after a drug hits the market.

FAERS doesn’t prove a drug causes a problem—it shows patterns. If hundreds of people report the same rare heart rhythm issue after taking a new antibiotic, regulators take notice. That’s how warnings for drugs like azithromycin and clarithromycin got updated. It’s also how they caught the link between SSRIs and low sodium in older adults, or why levothyroxine absorption issues became a big deal. These aren’t guesses. They’re patient stories, doctor notes, and hospital records stitched together into a safety net. And it’s not just for prescription drugs—OTC painkillers, supplements, and even vaccines show up here.

What makes FAERS powerful is who uses it: patients, caregivers, and doctors. If you had a weird reaction to a medication—dizziness, sweating, nausea, or worse—you can report it. That report goes into the system. It might seem small, but when thousands do the same thing, patterns emerge. That’s how we learned that generic levothyroxine can behave differently in some people, or why warfarin needs strict diet consistency. FAERS connects the dots between what’s in the bottle and what happens in real life.

Below, you’ll find detailed guides on the drugs and side effects that show up most often in FAERS reports. From QT prolongation risks to medication-induced sweating, hyponatremia in seniors, and why some generics don’t work the same—every article here is built from real-world safety data. You won’t find fluff. Just clear, practical info based on what’s actually happening to people taking these drugs.