Boxed warnings, FDA's most prominent label warning, explained

On Feb. 12, 2026, FDA announced that it had approved new labeling for six menopausal hormone therapy products. The change removed statements about cardiovascular disease, breast cancer and probable dementia from each product's boxed warning¹, which the agency's release called "the agency's most prominent safety-related warning." FDA said it had started the process in November 2025 and that, at its request, 29 drug companies had submitted proposed labeling changes.

Six years earlier the agency moved the other way on a common generic. On March 4, 2020, FDA said it was requiring a boxed warning for montelukast², an asthma and allergy drug, describing serious mental health side effects, and it required a new Medication Guide for patients at the same time.

Boxed warnings get added, rewritten and occasionally pulled back, and they sit on the labels of some of the most widely dispensed generics in the country. This piece explains what the federal rule requires of a box, how often prescription labels carry one according to published research and GxRadar's own count, and why a generic's box matches its brand's.

What the regulation requires

For prescription labels in the current format, the rule is 21 CFR 201.57(c)(1)³. It reads: "Certain contraindications or serious warnings, particularly those that may lead to death or serious injury, may be required by the FDA to be presented in a box." A boxed warning "ordinarily must be based on clinical data," the regulation says, though "serious animal toxicity may also be the basis" when clinical data are lacking.

Federal rules also fix the format. The box needs an uppercase heading that includes the word "WARNING" and names the general subject. It has to explain the risk briefly and point to the fuller discussion in the Contraindications or Warnings and Precautions section by section number. A shorter version also goes near the top of the label's Highlights. Under 201.57(a)(4)³, that summary may not exceed 20 lines, must sit inside a bolded box, and must be followed by a fixed sentence: "See full prescribing information for complete boxed warning."

Older labels that predate the current format fall under 21 CFR 201.80(e)⁴, which uses similar language. Special problems, "particularly those that may lead to death or serious injury, may be required by the Food and Drug Administration to be placed in a prominently displayed box," and FDA specifies where the box goes.

FDA's power to require new safety wording after a drug is on the market was strengthened in 2007. The Food and Drug Administration Amendments Act added section 505(o)⁶ to the drug law, and its paragraph (4) lets FDA notify an application holder of new safety information that should be in the labeling. The holder then has 30 days to submit proposed labeling changes, which the statute says can include "changes to boxed warnings," or to explain why it believes no change is warranted.

How many drugs carry one

The most complete published count is from a 2014 study in Therapeutic Innovation & Regulatory Science⁷. The authors, who included researchers at the University of California, San Francisco School of Pharmacy, reviewed prescription labels on the National Library of Medicine's DailyMed site in July 2012 and checked each boxed warning against a label on FDA's website. They found that 35 percent of labels (4,940 of 14,264) and 35 percent of drug groups (650 of 1,848) carried a validated boxed warning. Central nervous system drugs, cancer drugs and cardiovascular drugs were the most common classes, and 39 percent of the top 100 drugs used in 2012 were associated with one.

GxRadar repeated a simpler version of the count. In openFDA's drug label dataset⁸, updated Oct. 30, 2026, 11,827 of the 34,924 documents classified as human prescription drug labels contain a boxed warning section, or 34 percent. The two numbers measure slightly different things, since openFDA counts every version from every labeler and repackager, but they land within a point of each other 14 years apart.

Boxed warnings on common generics

Several of the generics GxRadar tracks carry a box on essentially every label. The headings below are copied from current labels in the openFDA dataset⁸; the counts are prescription label documents filed under each name.

Escitalopram, citalopram and fluoxetine, three more antidepressants GxRadar tracks, carried the same suicidality box on every prescription label in the dataset. Montelukast is the outlier in the table. Of the 15 montelukast labels without a parsed boxed-warning section, several carry effective dates in 2019, before FDA's 2020 action, and two contain the warning's text in another field. That pattern fits older label versions and gaps in openFDA's parsing. FDA's 2020 communication applied the requirement to montelukast as a molecule, brand and generics alike.

A box also tends to travel with other materials. The montelukast action came with a new Medication Guide², the paper handout that pharmacies give out with certain prescriptions; our explainer on Medication Guides and patient package inserts covers when those are required.

Why a generic's box matches the brand's

A generic copies its brand's labeling by rule. Under 21 CFR 314.94(a)(8)(iv)⁵, a generic application's proposed labeling "must be the same as the labeling approved for the reference listed drug," apart from differences such as manufacturer, formulation, expiration date, or uses carved out because of patents or exclusivity. A boxed warning is not one of the permitted differences, so it appears on the generic label as it does on the brand's. Our piece on generic labeling and carve-outs explains the exceptions.

The law also anticipates the case where the brand has left the market. Section 505(o)(4)(A)⁶ directs FDA, when it learns of new safety information, to notify "the responsible person or, if the same drug approved under subsection (b) is not currently marketed, the holder of an approved application under subsection (j)," the subsection that covers generics. A safety update can reach a generic-only market that way.

When a box is removed, the change works the same way in reverse. The hormone therapy decision applied first to six products, which included products from each of four categories: systemic estrogen-plus-progestogen therapy, systemic estrogen alone, systemic progestogen for women with a uterus who use systemic estrogen, and topical vaginal estrogen, according to FDA¹. GxRadar tracks estradiol 1 mg tablets, one of the molecules in those categories.

Reading a box on your own label

On a printed prescribing information sheet, or on a DailyMed page, the box appears twice: a short version in the Highlights at the top and the complete text at the start of the full prescribing information. Our guide to looking up a drug on DailyMed shows where to find both for the specific product in a bottle.

A boxed warning describes a serious risk and, often, the circumstances in which it arises, such as pregnancy, a genetic variant or a particular age group. What it means for one patient, and whether any monitoring applies, are questions for the prescriber or pharmacist. FDA's own release on the hormone therapy changes urged women to consult the updated labels and make decisions "working with their health care professionals."

FDA said the six February approvals were a first batch out of 29 company submissions. As the remaining labels are approved, the revised hormone therapy boxes will show up in DailyMed and in openFDA's data, where the label counts in this piece can be rerun.