An Overview of Black Box Warnings

medication bottle

Snap Decision / Getty Images

A black box warning appears on the label of a prescription medication to alert consumers and healthcare providers about safety concerns, such as serious adverse effects or life-threatening risks. A black box warning is the most serious medication warning required by the U.S. Food and Drug Administration (FDA). Any time after a drug is approved, the FDA can require the manufacturer to create a black box warning listed on the medication packaging.

How Black Box Warnings Work

The U.S. government is continuously monitoring the potential serious adverse effects of drugs. We're able to identify these adverse effects using the Adverse Event Reporting System as well as through the Office of Surveillance and Epidemiology, which examines FDA-approved medications post-market.

Most commonly, black box warnings are used to indicate potential adverse effects that need to be compared with potential benefit; however, black box warnings can also detail potential drug interactions, dosing instructions and monitoring.

The FDA requires that manufacturers of drugs with black box warnings should include information about which patients are candidates for the drug. This information is made available through your pharmacist and online. Furthermore, if you have any questions about prescription medication, it's a good idea to ask your pharmacists. (Pharmacists are valuable and underutilized patient resources.)

Most recently, there has been a substantial increase in the number of black box warnings required by the FDA. Despite this increase, however, there is still concern that many prescribers aren't vigilantly heeding these warnings, putting patient safety at risk.

Physicians, nurses, physician assistants, nurse practitioners, pharmacists, drug manufacturers and consumers (you) can submit reports about drugs online at FDA MedWatch using standardized forms. The results from these forms comprise the Adverse Event Reporting System. Between 1969 (date of inception) and 2010, more than 4 million forms have been submitted to the FDA.

Black box warnings can apply to either individual drugs or whole classes of drugs.

Also Known As: black label warning, boxed warning


  • The FDA requires a black box warning on all antidepressants because of an increased risk of suicidal thinking and behavior in young adults aged between 18 and 24 during initial treatment—generally the first one to two months of therapy. This black box warning was initially created in 2004 and expanded to cover patients aged younger than 24 years in 2007.
  • Angiotensin-receptor blockers (ARBs like enalapril or losartan) present risk to the fetus during gestation. Thus, these antihypertensive medications should be avoided during pregnancy. Much like ARBS, angiotensin-converting enzyme inhibitors (ACE inhibitors or "statins") are antihypertensive medications that are also dangerous to the developing fetus and should be avoided during pregnancy.
  • Aspirin can cause Reye's syndrome in children. Reye's syndrome is a rare syndrome that causes swelling of the liver or brain. The development of Reye's syndrome in children has been linked to the administration of aspirin in children who are recovering from chickenpox or the flu. The administration of aspirin to children must be carefully considered by a physician. Additionally, aspirin has a more general black box warning that warns of allergy.
  • Oral contraceptive pills warn of increased risk of stroke in women aged 35 years and older.
  • Ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs) sport black box warnings linking them to gastrointestinal bleeding and ulcers as well as hemorrhagic stroke (brain bleeds).

A Word From Verywell

If you or a loved one is taking a drug with a black-box warning, it behooves you to familiarize yourself with the potential risks of such medications. In addition to searching the web, feel free to ask your physician, pharmacist or another health care professional for advice and guidance.

Was this page helpful?

Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • Eisendrath SJ, Cole SA, Christensen JF, Gutnick D, Cole M, Feldman MD. Depression. In: Feldman MD, Christensen JF, Satterfield JM. eds. Behavioral Medicine: A Guide for Clinical Practice, 4e. New York, NY: McGraw-Hill; 2014. 

  • O'Connor NR. FDA boxed warnings: how to prescribe drugs safely. Am Fam Physician. 2010;81(3):298-303.