A review of data from the FDA Adverse Event Reporting System and published case reports identified 82 cases of anaphylaxis associated with use of glatiramer acetate that occurred between December 1996 and May 2024, including 51 requiring hospitalization and 6 that were fatal. Most cases occurred within 12 months after starting treatment with glatiramer (one was a sudden death after the first dose), but about 25% of the cases occurred >12 months after the drug was started. Anaphylaxis typically occurred within 1 hour after injection.1

Glatiramer acetate and interferon beta (Betaseron, and others) are typically used to treat less active cases of relapsing MS; they are less effective than other disease-modifying drugs, but they cause less toxicity. Glatiramer is generally better tolerated than interferon and is similarly effective, but it must be injected more frequently.2 Anaphylaxis has also occurred with use of interferon beta.

Patients receiving glatiramer acetate should be counseled about the risk of anaphylaxis and cautioned that symptoms of anaphylaxis can overlap with those of more typical injection-related reactions, such as flushing, shortness of breath, rash, and hives, which typically occur within minutes after injection and are generally self-limited.1