Key takeaways
Granisetron (Kytril) and Emend (aprepitant) are both medications used to prevent nausea and vomiting caused by chemotherapy, but they work in different ways and belong to different drug classes. Granisetron is an antiemetic that blocks serotonin receptors, while Emend is an NK1 receptor antagonist that blocks certain chemicals in the brain. Granisetron is available in oral and intravenous forms, whereas Emend is available as oral capsules, an oral solution, and an injectable form. Granisetron is typically taken only on the days of chemotherapy or radiation, while Emend is taken for the first three days of each chemotherapy cycle. Granisetron can be more expensive and has a risk of causing serotonin syndrome when taken with other medications affecting serotonin levels. Granisetron can also cause heart-related problems if you take medications that cause QT prolongation. Emend, on the other hand, has many drug interactions, including with hormonal birth control and certain medications for Tourette syndrome, but it does not cause QT prolongation. Both medications are not effective for treating nausea and vomiting that has already started; they are only for prevention.
