Steroid-sparing Therapy (Olanzapine) Versus Dexamethasone-based Therapy for Chemotherapy-induced Nausea and Vomiting

The purpose of this research is to compare two drugs that are routinely used as standard of care for treating nausea and vomiting caused by chemotherapy. This study aims to see if the drug olanzapine is as good as the steroid drug dexamethasone for preventing nausea and vomiting after chemotherapy. Both drugs are listed as appropriate treatment options in the most recent version of National Comprehensive Cancer Network guidelines on Antiemesis.

Inclusion Criteria: * 18 years and older * confirmed cancer diagnosis * starting cycle 1 of an FDA approved treatment that is categorized as high-emetogenic (nausea and vomiting inducing) chemotherapy per National Comprehensive Cancer Network® guidelines * Eastern Cooperative Oncology Group performance score of 0 or 1 * appropriate renal function * appropriate hepatic function * appropriate hematologic function. Exclusion Criteria: * Patients will be excluded if they experience nausea or vomiting up to 24 hours before chemotherapy, * currently on a glucocorticoid therapy * contraindication to glucocorticoid therapy * taking any medication that has antiemetic properties. * scheduled or planned to receive radiation within one week of or concurrently with chemotherapy * brain metastases.