Frequently Asked Questions

All data comes from the openFDA Drug Adverse Events API, which provides access to the FDA Adverse Event Reporting System (FAERS). FAERS is maintained by the FDA's Center for Drug Evaluation and Research (CDER).

We periodically refresh our data from the openFDA API. The FDA updates FAERS quarterly, with new reports typically appearing within a few months of submission. For the most current data, you can query the openFDA API directly.

The FDA defines an adverse event as any undesirable medical occurrence associated with the use of a drug, whether or not the drug caused it. This includes side effects, medication errors, product quality problems, and any health issue that happened while a patient was taking the drug.

Side effects are known, expected reactions listed on a drug's label. Adverse events are any undesirable medical occurrence during drug use, regardless of whether the drug caused it. FAERS collects adverse events, which is a broader category. See our guide on this topic for more detail.

Not necessarily. Widely prescribed drugs naturally accumulate more reports because more people are taking them. A drug with 50,000 reports taken by 30 million people annually may be safer per-patient than a drug with 1,000 reports taken by 5,000 people. Always consider the size of the patient population.

Yes. FAERS data has several known biases. Reporting is mostly voluntary, so only an estimated 1-10% of adverse events are reported. Drugs that receive media attention get more reports. Serious events are reported more often than mild ones. Newly approved drugs may be under closer scrutiny. These biases mean FAERS data is best used for signal detection, not for calculating true incidence rates.

The total report count shows how many adverse event reports in the FAERS database list that drug. "Serious Reports" are those involving death, hospitalization, disability, or life-threatening outcomes. "Death Reports" are those where the outcome was death — but this does not mean the drug caused the death.

The death report ratio shows death reports as a percentage of total reports. It is color-coded: green (Low, under 1%), yellow (Moderate, 1-5%), and red (High, over 5%). A high ratio often reflects the severity of the condition being treated rather than the drug's danger. Chemotherapy drugs, for example, typically have high ratios because cancer patients have elevated mortality.

Severity badges (Low, Moderate, High) are based on the death report ratio. They provide quick visual context but should not be used as the sole measure of a drug's safety. Always consider the drug's therapeutic area, patient population, and total prescribing volume.

"Drug ineffective" means the reporter indicated the drug did not achieve its intended effect. It is not a side effect but a report about efficacy. It appears frequently because patients and doctors commonly report when a treatment fails. See our guide on common reactions for more explanation.

Drug classes on this site use the Established Pharmacologic Class (EPC) tags from the openFDA API. These classify drugs by their mechanism of action or therapeutic effect. A drug may belong to multiple classes. Our drug class pages aggregate adverse event data across all drugs in each class.

You can compare the types of adverse events reported for different drugs, but raw report counts should not be directly compared between drugs without accounting for differences in prescribing volume, patient population, and time on market. Comparing drugs within the same drug class provides somewhat better context.

No. Never stop taking a prescribed medication without consulting your doctor. Abruptly stopping some medications can cause serious withdrawal effects or allow your condition to worsen. If you have concerns, talk to your healthcare provider.

You can report through the FDA MedWatch online form, by calling 1-800-FDA-1088, or through your healthcare provider. See our reporting guide for step-by-step instructions.

Use this data to inform conversations with your healthcare provider, not to make medical decisions on your own. Remember that reports do not prove causation, high counts often reflect high usage, and this data cannot replace clinical judgment. For personalized medical advice, consult your doctor or pharmacist.

No. Drug Fact Check is an informational resource that makes FDA data more accessible. It is not medical advice and should not be used to diagnose conditions or make treatment decisions. Always consult a qualified healthcare professional.

For official drug information, visit DailyMed for drug labels, Drugs@FDA for approval information, or ask your pharmacist for the patient medication guide.

The underlying data is publicly available through the openFDA API. For academic research, we recommend accessing the API directly to ensure you have the most current and complete data. Please cite openFDA as the data source.