Alternate Pre-med in Anti-Cluster of Differentiation 20 (CD20) Pilot Project

The purpose of this study is to assess and compare how well multiple sclerosis (MS) patients tolerate cetirizine versus diphenhydramine as a pre-medication before receiving anti-CD20 infusion therapy of ocrelizumab, ublituximab or rituximab. The study will also compare the safety of cetirizine versus diphenhydramine as a pre-medication for preventing infusion reactions in MS patients receiving anti-CD20 infusion therapy.

Inclusion Criteria: * Ages ≥18 years * Able to read and speak in English or Spanish * Able to and willing to give informed consent * Diagnosis of Multiple Sclerosis (MS) * Patients starting or currently receiving ocrelizumab, ublituximab, rituximab Exclusion Criteria: * Adults unable or unwilling to consent * Patients younger than 18 years of age * Pregnant women * Known hypersensitivity to cetirizine or any of its ingredients or hydroxyzine * Moderate or severe renal impairment (creatinine clearance or 11-31 mL/min or worse) * Patients with prior hypersensitivity reactions on additional preventative measures (e.g. H1 and H2/proton-pump inhibitor (PPI) the night prior to the infusion due to history of reactions)