Mild cases of angioedema may not need treatment. If treatment is needed, over-the-counter or prescription antihistamines may be prescribed. For hereditary angioedema, a chronic condition, treatments include: C1 inhibitor, bradykinin B2-receptor antagonists, and kallikrein inhibitors. For anaphylaxis, the rapid administration of injected epinephrine is needed to prevent anaphylactic shock and other potentially life-threatening symptoms.