How and Why to Report Side Effects to the FDA

Your Report Can Save Lives

The adverse event data you see on Drug Fact Check exists because someone — a patient, a doctor, a pharmacist — took the time to report it to the FDA. Every data point in the FAERS database represents a report that was filed. Without these reports, the FDA would have limited ability to detect drug safety problems after a medication reaches the market.

Reporting adverse events is a critical part of the drug safety ecosystem. Clinical trials typically involve a few thousand patients over a limited period. Once a drug is approved and prescribed to millions of people, new safety issues may emerge that were too rare or too slow-developing to be detected in trials. The voluntary reporting system is how many of these issues come to light.

What Should You Report?

You should consider filing an FDA adverse event report when:

• You experience a side effect that is not listed on the drug’s label or that seems unusually severe
• A medication does not work as expected (drug ineffective)
• You suspect a drug interaction between two or more medications
• You notice a quality problem with a medication — such as tablets that are discolored, broken, or have an unusual odor
• A medication error occurred — such as receiving the wrong drug or wrong dose at a pharmacy
• You experience a serious outcome — hospitalization, disability, a life-threatening event, or any outcome that required medical intervention

You do not need to be certain that the drug caused the problem. The FDA explicitly states that suspicion alone is sufficient reason to report. Determining causation is the FDA’s job, not yours.

How to File a Report

Online (Recommended)

The fastest and most convenient way to report is through the FDA’s MedWatch Online Voluntary Reporting Form. The form walks you through providing:

• Your contact information (or you can report anonymously)
• The product name, manufacturer, and dose
• A description of the adverse event
• Relevant dates (when the drug was started, when the event occurred)
• The outcome (hospitalization, disability, death, etc.)
• Other medications the patient was taking
• Relevant medical history

The online form typically takes 15 to 30 minutes to complete, depending on how much detail you include.

By Phone

You can call 1-800-FDA-1088 (1-800-332-1088) to report by phone. Representatives are available Monday through Friday, and you can leave a message outside of business hours.

By Mail or Fax

Download the MedWatch 3500 form (PDF) from the FDA website, fill it out, and mail or fax it to the address provided on the form.

Through Your Healthcare Provider

If you report your adverse event to your doctor, pharmacist, or other healthcare provider, they can file a MedWatch report on your behalf. Healthcare professionals often provide more detailed clinical information, which can make the report more useful for FDA analysis.

What Information to Include

The more detail you provide, the more useful your report will be. Key information includes:

About the patient

• Age and sex
• Weight (if relevant)
• Relevant medical history
• Known allergies

About the drug

• Exact product name (brand name or generic)
• Manufacturer (found on the packaging)
• Dose and frequency
• Route of administration (oral, injection, topical, etc.)
• Date the drug was started
• Date the drug was stopped (if applicable)
• Why the drug was prescribed

About the adverse event

• What happened, described in as much detail as possible
• When the symptoms started
• How long the symptoms lasted
• Whether the event resolved after stopping the drug (dechallenge)
• Whether the event recurred after restarting the drug (rechallenge)
• What treatment was needed for the adverse event

About other medications

• All other prescription medications being taken
• Over-the-counter drugs, supplements, and herbal products
• Any recent changes to the medication regimen

What Happens After You Report

Once your report is submitted, it enters the FAERS database. Here is what happens next:

Initial processing. The FDA’s Center for Drug Evaluation and Research (CDER) receives and codes the report using MedDRA terminology. The report is entered into the FAERS database.

Signal detection. FDA safety evaluators use statistical and computational methods to scan the database for unusual patterns. If a particular drug-event combination occurs more frequently than expected, it may be flagged as a potential safety signal.

Signal evaluation. When a signal is detected, FDA reviewers conduct a more thorough investigation. They examine the individual case reports, review medical literature, and may consult with outside experts.

Regulatory action. If the investigation confirms a safety concern, the FDA can take several actions:

• Issue a Drug Safety Communication to inform the public
• Require label changes, including new warnings or contraindications
• Require a Risk Evaluation and Mitigation Strategy (REMS)
• In extreme cases, request a voluntary market withdrawal

Public availability. Adverse event reports are made publicly available (with patient identifiers removed) through the openFDA API, which is the data source for Drug Fact Check. Your report, anonymized and coded, may eventually appear in the data on this site.

Common Reasons People Do Not Report

Despite the importance of adverse event reporting, studies estimate that only 1 to 10 percent of adverse events are actually reported. Common barriers include:

“I was not sure it was the drug.” You do not need to be certain. The FDA wants to receive reports even when the connection is uncertain.

“My doctor already knows.” Your doctor knowing about your side effect is not the same as it being reported to the FDA. Unless your doctor files a MedWatch report, the information does not enter the FAERS database.

“It was a minor side effect.” Even minor side effects matter. Patterns of minor effects across many patients can indicate a broader safety issue. And what seems minor to you may be a clue to a more serious underlying problem.

“I did not know I could report.” Now you do. Any individual — patient, family member, or caretaker — can file a report with the FDA.

“It takes too long.” The online form takes 15 to 30 minutes. Consider that your report could contribute to identifying a safety problem that affects thousands of other patients.

Healthcare Professionals Have Additional Reporting Channels

If you are a healthcare professional, you have additional options:

• MedWatch 3500A form — specifically designed for mandatory (manufacturer) and voluntary (healthcare professional) reporting
• Electronic reporting — through the FDA’s Electronic Submissions Gateway for organizations that submit many reports
• Vaccine adverse events — reported through VAERS rather than MedWatch

Healthcare professionals are not legally required to report to the FDA (except in certain circumstances involving vaccines), but the FDA strongly encourages reporting. Professional reports are especially valuable because they typically include more detailed clinical information.

Manufacturer Reporting Requirements

Drug manufacturers have a legal obligation to report adverse events to the FDA. If a manufacturer receives information about a serious and unexpected adverse event, they must submit a report within 15 calendar days. For non-serious events, reports are submitted in periodic safety reports.

If you report a side effect to a drug manufacturer’s customer service line, they are required to forward serious reports to the FDA. However, for the most direct route, consider filing your own MedWatch report as well.

Your Contribution to Drug Safety

Every report in the FAERS database exists because someone took the time to document their experience. The data on Drug Fact Check represents millions of these individual contributions. By reporting your own adverse events, you become part of this collective effort to make medications safer for everyone.

The FDA’s ability to protect public health depends on the quality and quantity of adverse event reports they receive. Your single report might be the data point that triggers an investigation, leads to a label change, or prevents harm to future patients.

This guide is for informational purposes only. If you are experiencing a medical emergency, call 911 or go to your nearest emergency room.