Aprepitant and fosaprepitant
Say it: uh-PREP-ih-tant and FOSS-uh-PREP-ih-tant · Brand names: Emend, Cinvanti, Aponvie, Focinvez
Aprepitant and fosaprepitant are medicines that help prevent nausea and throwing up from chemotherapy.
What it is
Some nausea comes from a brain chemical called substance P. These medicines block substance P from reaching its target, called the NK1 receptor. Fosaprepitant is a form given in a vein that the body turns into aprepitant.
Often used for
- preventing nausea and throwing up from chemotherapy, along with other nausea medicines
- preventing delayed nausea that starts a day or more after chemotherapy
- preventing nausea after surgery (one form of aprepitant)
How you get it
Aprepitant comes as capsules, often taken for 3 days starting before chemotherapy, or as a drip into a vein. Fosaprepitant is a drip into a vein, usually given once before chemotherapy. Both are used with other nausea medicines. Your schedule may be different.
Common side effects and what helps
- Feeling tired or weak. Rest when you need to.
- Diarrhea. Drink plenty of fluids.
- Hiccups. These usually go away on their own.
- Indigestion or belly pain. Eat small meals.
- Less appetite. Try small snacks through the day.
- Pain, redness, or swelling where the drip goes in (fosaprepitant). Tell your nurse right away.
Call your care team right away if you have
- Signs of an allergic reaction, like a rash all over, swelling of the face or throat, or wheezing
- Pain, burning, swelling, or hardness where the drip went in that gets worse
- A skin rash with blisters or peeling
- Nausea or throwing up that does not stop, or you cannot keep fluids down
- A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher
Before you start, tell your team
- All medicines you take. These medicines interact with many others.
- If you take warfarin. Your team may check your blood more often after treatment.
- If you use birth control pills, patches, or rings. They may not work as well.
- If you have liver problems
- If you are pregnant, may become pregnant, or are breastfeeding
Good to know
- Hormone birth control may not work well during treatment and for 1 month after. Use a backup method, like condoms.
- If you take warfarin, you may need extra blood tests in the week or two after each dose.
- These medicines can raise the levels of some other medicines, including steroids like dexamethasone. Your team may change those doses.
- They should not be taken with pimozide.
At home
- If you take the capsules, take the first one before chemotherapy as your team told you, then the rest on the next days.
- Swallow the capsules whole.
- If you miss a dose, ask your team what to do.
- Store at room temperature, away from children.
Questions to ask
- Will I get this as capsules or a drip?
- What other nausea medicines will I take with it?
- Do I need backup birth control, and for how long?
Side effect guides
Sources
Quick answers
- What is Aprepitant and fosaprepitant?
- Aprepitant and fosaprepitant are medicines that help prevent nausea and throwing up from chemotherapy. Brand names: Emend, Cinvanti, Aponvie, Focinvez.
- What is Aprepitant and fosaprepitant used for?
- preventing nausea and throwing up from chemotherapy, along with other nausea medicines; preventing delayed nausea that starts a day or more after chemotherapy; preventing nausea after surgery (one form of aprepitant).
- How is Aprepitant and fosaprepitant given?
- Aprepitant comes as capsules, often taken for 3 days starting before chemotherapy, or as a drip into a vein. Fosaprepitant is a drip into a vein, usually given once before chemotherapy. Both are used with other nausea medicines. Your schedule may be different.
- What are the common side effects of Aprepitant and fosaprepitant?
- Feeling tired or weak. Diarrhea. Hiccups. Indigestion or belly pain. Less appetite. Pain, redness, or swelling where the drip goes in (fosaprepitant).
- When should I call my care team while taking Aprepitant and fosaprepitant?
- Signs of an allergic reaction, like a rash all over, swelling of the face or throat, or wheezing; Pain, burning, swelling, or hardness where the drip went in that gets worse; A skin rash with blisters or peeling; Nausea or throwing up that does not stop, or you cannot keep fluids down; A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.