Skip to main content

Fosaprepitant

Generic name: fosaprepitant [ FOS-a-PREP-i-tan-t ]
Brand name: Emend for Injection
Dosage form: intravenous powder for injection (150 mg)
Drug class: NK1 receptor antagonists

Medically reviewed by Drugs.com on Dec 31, 2020. 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.

Fosaprepitant is given ahead of time and will not treat nausea or vomiting that you already have.

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

Warnings

You should not use fosaprepitant if you also take pimozide. Using these drugs together can cause unwanted or dangerous effects.

Before taking this medicine

You should not be treated with fosaprepitant if you are allergic to fosaprepitant or aprepitant, or if you take another medicine called pimozide (Orap). Fosaprepitant can cause unwanted or dangerous effects when used with pimozide.

Tell your doctor if you have ever had:

Tell your doctor if you are pregnant or breastfeeding.

Fosaprepitant can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. To prevent pregnancy while using fosaprepitant, use a barrier form of birth control: condom, diaphragm, cervical cap, or contraceptive sponge.

Keep using a barrier form of birth control for at least 1 month after each dose of fosaprepitant.

How is fosaprepitant given?

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

The first dose of fosaprepitant is usually given on the first day of your chemotherapy treatment.

You may also be given other medicines, including aprepitant (Emend taken by mouth), to further help prevent nausea and vomiting.

Fosaprepitant is not for long-term use.

If you also take warfarin (Coumadin, Jantoven), you may need extra "INR" or prothrombin time tests after you have received fosaprepitant.

What happens if I miss a dose?

Since fosaprepitant injection is given only once on the first day of your chemotherapy treatment, you are not likely to be on a dosing schedule.

What happens if I overdose?

Since fosaprepitant is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving fosaprepitant?

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

Fosaprepitant side effects

Get emergency medical help if you have signs of an allergic reaction: hives, rash, itching, skin sores or peeling; warmth or tingly feeling; fast or weak heartbeats, severe dizziness; trouble breathing or swallowing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • pain, redness, swelling, burning, blistering, or skin changes where the chemotherapy medicine was injected;

  • a light-headed feeling, like you might pass out;

  • pain or burning when you urinate; or

  • low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath.

Common side effects may include:

  • weakness, tired feeling;

  • fever;

  • low blood cell counts;

  • painful urination;

  • diarrhea, indigestion; or

  • pain, numbness, or weakness in your arms or legs.

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.

What other drugs will affect fosaprepitant?

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