In what sequence should you administer premedications prior to paclitaxel: Should the antihistamine be given first or the steroid? Does it matter? —Name withheld on request

Premedications are administered prior to paclitaxel (Taxol), as well as some other chemotherapy agents, to reduce the incidence and severity of infusion-related reactions. The paclitaxel premedication regimen consists of an antihistamine (eg, diphenhydramine), a corticosteroid (eg, dexamethasone), and an H2 receptor antagonist (eg, famotidine).

Early studies of paclitaxel demonstrated high rates of hypersensitivity reactions. The mechanism through which paclitaxel produces hypersensitivity reactions is not well characterized, and may be due to the Cremophor EL present in traditional paclitaxel products. A premedication regimen was developed to reduce the severity and incidence of these reactions. Originally, the antihistamine and corticosteroid were administered 12 hours and 6 hours prior to paclitaxel administration. As some patients may have difficulty adhering to this schedule, intravenous regimens have also been studied. These regimens, in which the antihistamine, corticosteroid, and H2 receptor antagonist are administered intravenously 30 to 60 minutes prior to paclitaxel, have been shown to be similarly effective compared to the oral regimens. Administering premedications within the appropriate time frame is important for efficacy; so long as the medications are administered within this time frame, the exact order of administration is flexible and should be done in accordance with your local standard of practice.