If a patient has a known allergic reaction to an antineoplastic medication, which types of medications are given as pretreatment preparation? (Select all that apply.)

When a patient has a known hypersensitivity reaction to an antineoplastic medication, pretreatment protocols are designed to blunt the immune-mediated response. Antihistamines (such as diphenhydramine) block H1 receptors and reduce histamine-mediated symptoms including urticaria, pruritus, and bronchospasm that are common during hypersensitivity reactions. Corticosteroids (such as dexamethasone or hydrocortisone) suppress the inflammatory cascade more broadly, decreasing capillary permeability and modulating the immune response. Acetaminophen is included in many premedication regimens to reduce fever and general discomfort associated with infusion reactions. Together, these three agents form the standard pretreatment triplet used before chemotherapy agents with high hypersensitivity profiles, such as paclitaxel, docetaxel, and platinum compounds. Antiemetics are used to manage chemotherapy-induced nausea and vomiting rather than to prevent allergic reactions, so they are not part of the hypersensitivity pretreatment protocol specifically. Antacids are used for GI protection (particularly with corticosteroids in long-term use) but are not part of the standard acute hypersensitivity premedication regimen for antineoplastic infusions. The nurse must understand the distinction between managing allergy risk and managing other chemotherapy side effects.