What medications should patients carry if they have a history of anaphylaxis?

Patients with a history of anaphylaxis should carry at least two epinephrine auto-injectors at all times, such as EpiPen or generic equivalents, and know how to use them. They should administer epinephrine immediately at the first sign of a severe allergic reaction and call emergency services even if symptoms improve, because biphasic reactions can occur hours later. Antihistamines like diphenhydramine are secondary treatments that help with itching and hives but cannot reverse airway obstruction or cardiovascular collapse.