Most people undergoing chemotherapy receive anti-nausea (anti-emetic) medications to prevent nausea and vomiting. These drugs, given alone or in combination, can be taken in pill form or administered through a vein in your arm. Your doctor advises which to use based on the treatment you're receiving. Medications used to prevent nausea and vomiting include: 1  Alprazolam (Niravam, Xanax)  Aprepitant (Emend)