Key takeaways
Ondansetron (Zofran) and Emend (aprepitant) are both medications used to prevent nausea and vomiting, but they work in different ways and are used in different situations. Ondansetron is a serotonin blocker that can be used for nausea and vomiting caused by chemotherapy, radiation therapy, and surgery. It comes in various forms, including tablets, dissolvable tablets, liquid, and injections, and is available as a lower-cost generic. Emend, on the other hand, is an NK1 receptor antagonist specifically used to prevent nausea and vomiting from chemotherapy and must be taken along with other medications like dexamethasone and a serotonin antagonist. Emend is available as capsules and an oral solution, but it is not used to treat nausea and vomiting once they have started. While both medications can cause tiredness and diarrhea, Emend has additional side effects like weakness and indigestion, and it interacts with many other medications, including hormonal birth control. Unlike ondansetron, Emend does not cause QT prolongation, a heart rhythm problem.
