Boxed Warning

Deep dive

Boxed Warning: complete reference

A boxed warning (formerly called "black box warning") is the FDA's strongest warning label на a prescription drug, indicating serious or life-threatening risk. The warning appears in a distinctive black-bordered box at the top of the prescribing information. Required when "there is an adverse reaction so serious в proportion to the potential benefit from the drug that it is essential it be considered." All GLP-1 receptor agonists carry boxed warnings для potential risk of thyroid C-cell tumors (including medullary thyroid carcinoma) based on rodent studies showing dose-dependent thyroid C-cell tumor development. Human relevance remains theoretical — humans have lower thyroid C-cell density and no clear human signal has emerged from clinical trials or post-marketing surveillance. The warning translates to contraindication для patients с personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2). Many prescribers also recommend baseline thyroid evaluation, particularly если family history concerns exist.

In practice

When you start Wegovy, your prescriber asks "any thyroid cancer in your family?" — that's screening for the boxed warning contraindication.

Clinical context

The thyroid boxed warning is theoretical (rodent-based) but firm contraindication для MTC/MEN 2 history families.