Effective Use of Olanzapine for Chemotherapy-Induced Nausea and Vomiting in a Patient Receiving Dose-Adjusted Rituximab, Etoposide, Prednisone, Vincristine (Oncovin®), Cyclophosphamide, and Doxorubicin (R-EPOCH): A Case Report

Dose-adjusted (DA) rituximab, etoposide, prednisone, vincristine (Oncovin^®), cyclophosphamide, and doxorubicin (R-EPOCH) is a multiday chemotherapy regimen that includes anthracyclines and cyclophosphamide. Although olanzapine is used to prevent chemotherapy-induced nausea and vomiting (CINV), its efficacy in patients receiving DA-R-EPOCH has not yet been reported. We describe a case in which olanzapine was effective in preventing CINV during DA-R-EPOCH treatment. A 21-year-old woman was diagnosed with primary mediastinal large B-cell lymphoma. The patient had some CINV risk factors associated with a lower risk, such as no history of motion sickness or morning sickness (no history of pregnancy), as well as factors associated with a higher CINV risk, including a lack of habitual alcohol consumption and no history of smoking. The patient received prophylactic antiemetic therapy with olanzapine (5 mg after dinner for six days), palonosetron, and fosnetupitant during DA-R-EPOCH therapy. Prednisolone was administered at 60 mg/m² for five days as part of the DA-R-EPOCH regimen; it also served as a corticosteroid with antiemetic activity. From days 1 to 10 of treatment, the food intake rate remained above 70%. Grade 1 nausea was observed on days 4 and 5, with no vomiting during the treatment period. Adverse events, such as constipation and somnolence, were also noted. A four-drug antiemetic regimen, including olanzapine, supported the feasibility of preventing CINV in this case involving DA-R-EPOCH therapy. However, adverse events potentially related to olanzapine were observed, suggesting the need for further investigation into its optimal dosage.