Skip to main content


Generic name: fosaprepitant [ FOS-a-PRE-pi-tant ]
Brand names: Emend for Injection, Focinvez
Dosage forms: intravenous powder for injection (150 mg), intravenous solution (150 mg/50 mL)
Drug class: NK1 receptor antagonists

Medically reviewed by on Jun 6, 2024. Written by Cerner Multum.

What is fosaprepitant?

Fosaprepitant is used together with other medications to prevent nausea and vomiting that may be caused by chemotherapy in adults and children at least 6 months old who weigh at least 6 kg (13 pounds).

Fosaprepitant is not used to treat nausea and vomiting that you already have.

Fosaprepitant may also be used for purposes not listed in this medication guide.

Fosaprepitant side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Some side effects may occur during the injection. Tell your medical caregiver if you feel dizzy, nauseated, light-headed, itchy, sweaty, or have a headache, chest tightness, back pain, trouble breathing, or swelling in your face.

Fosaprepitant may cause serious side effects. Call your doctor at once if you have:

Common side effects of fosaprepitant may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Tell your doctor about all your other medicines. Some drugs should not be used with fosaprepitant.

Before taking this medicine

You should not use fosaprepitant if you are allergic to fosaprepitant or similar medicines such as aprepitant.

Some drugs should not be used with fosaprepitant. Your treatment plan may change if you also use pimozide.

Tell your doctor if you have ever had:

It is not known if fosaprepitant will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Ask a doctor if it is safe to breastfeed while using this medicine.

Fosaprepitant can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. Use barrier birth control to prevent pregnancy: condom, diaphragm, cervical cap, or contraceptive sponge.

Ask your doctor about the best form of birth control while you are using fosaprepitant. Keep using the barrier form of birth control for 1 month after your last dose.

How is fosaprepitant given?

Fosaprepitant is given as an infusion into a vein. A healthcare provider will give you this injection.

Fosaprepitant is not for long-term use.

Fosaprepitant is usually given on the first day of chemotherapy treatment.

Tell your medical caregivers if you feel any burning or pain when fosaprepitant is injected.

You may be given other medications to further help prevent nausea and vomiting.

You may need blood tests after receiving fosaprepitant if you also take a blood thinner called warfarin.

What happens if I miss a dose?

In a medical setting you are not likely to miss a dose of fosaprepitant.

What happens if I overdose?

In a medical setting an overdose would be treated quickly.

What should I avoid while receiving fosaprepitant?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect fosaprepitant?

Sometimes it is not safe to use certain medicines at the same time. Some drugs can affect your blood levels of other drugs you use, which may increase side effects or make the medicines less effective.

Many drugs can affect fosaprepitant. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any medicine you start or stop using.

Frequently asked questions

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.