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Emend is available as capsules you can swallow. The capsules come in multiple strengths. It may also be given intravenously.

How It Works

Aprepitant prevents and controls nausea and vomiting by blocking the effects of a chemical in the brain. That chemical is called P/neurokinin 1 (NK1) receptor antagonist.

Why It Is Used

Aprepitant is used to prevent and control nausea and vomiting caused by chemotherapy. It is always used in combination with serotonin antagonists (such as ondansetron) and dexamethasone.

Aprepitant is most often used when the other drugs used to treat nausea and vomiting have not worked well enough.

How Well It Works

Aprepitant, when combined with ondansetron and dexamethasone as part of a 3-day regimen, prevents both acute and delayed nausea and vomiting caused by chemotherapy.

Side Effects

Side effects can occur with aprepitant and may include:

  • Dehydration.
  • Dizziness.
  • Diarrhea.
  • Hiccups.
  • Weakness and fatigue.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Aprepitant should be used only under the supervision of a medical oncologist or hematologist. It is approved for use only in combination with ondansetron and dexamethasone for the treatment of nausea and vomiting caused by chemotherapy. It also may do a better job than other drugs at controlling nausea and vomiting that occurs more than 1 day after treatment.

Aprepitant interacts with many other drugs. Be sure that your doctor knows all the prescription and over-the-counter drugs you are taking.

Blood-thinning drugs, such as warfarin, may not work as well when you take aprepitant. If you are taking a blood thinner, you will need frequent blood tests to make sure that your dose is high enough.

Aprepitant decreases the effectiveness of birth control pills. If you are taking birth control pills, your doctor will help you choose another method of birth control.

Aprepitant has been approved for use by adults older than 18. The safety of this drug for use in children has not been tested.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Brian Leber, MDCM, FRCPC - Hematology
Last Revised February 9, 2011

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.