The FDA has issued a new Boxed Warning for glatiramer acetate (Copaxone, Glatopa), a widely used treatment for relapsing multiple sclerosis, citing the risk of rare but potentially life-threatening allergic reactions, including anaphylaxis.

Anaphylaxis, which can occur at any time during treatment—even years after initiating the medication—has been associated with severe outcomes, including hospitalization and death. FDA reported that most cases occurred within 1 hour of injection. Of 82 confirmed cases between 1996 and May 2024, 51 required hospitalization, including 13 in intensive care, and 6 resulted in death.

The agency emphasized distinguishing anaphylaxis from common immediate post-injection reactions, which are typically mild and self-limiting, resolving within 30 minutes. Symptoms of post-injection reactions include flushing, chest pain, and shortness of breath.

Health care professionals are urged to educate patients on recognizing symptoms and emphasize the importance of prompt treatment for anaphylaxis. The updated prescribing information advises discontinuing glatiramer acetate permanently in patients experiencing anaphylaxis unless a clear alternative cause is identified.

Glatiramer acetate, approved since 1996, remains a key therapy for multiple sclerosis (MS), reducing the frequency of relapses by modulating immune system activity. Despite over 3 million patient-years of postmarket exposure, the 82 anaphylaxis cases underscore the importance of monitoring for adverse events.

To report side effects, patients and health care providers can use the FDA MedWatch program. The full FDA communication includes additional safety recommendations and prescribing information.