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Treatment Name: Fosaprepitant (Emend®)

Fosaprepitant (Emend®) is a Supportive Care Therapy to prevent Nausea and Vomiting

How does fosaprepitant (Emend®) work?

Fosaprepitant is designed to block receptors in your brain that can cause nausea and vomiting called substance P/neurokinin 1 (NK1) receptors.

Chemotherapy can cause a molecule called substance P to be released, which bind to NK1 receptors in the brain and trigger nausea and vomiting. Fosaprepitant binds to NK1 receptors instead of substance P, and thereby stops the reflex to vomit.

What are the fosaprepitant (Emend®) goals of therapy?

Fosaprepitant is given to prevent both early and delayed nausea and vomiting from chemotherapy and is commonly given on a scheduled basis just before chemotherapy. Fosaprepitant is not usually used to treat nausea and vomiting. When a medicine is given to prevent nausea and vomiting, it is known as prophylaxis, or prophylactic therapy.


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How is fosaprepitant (Emend®) therapy given to prevent nausea and vomiting?

Fosaprepitant is usually given in an outpatient infusion center, approximately 30 minutes before chemotherapy to prevent nausea and vomiting.

  • Fosaprepitant 150 mg intravenous (I.V) infusion over 20 to 30 minutes on Day 1 of chemotherapy

Fosaprepitant is typically given, along with other anti-nausea medications, for chemotherapy regimens that have a high risk of nausea and vomiting and regimens that may cause delayed nausea and vomiting. Duration of therapy depends upon response, tolerability, and number of cycles chemotherapy prescribed.

On occasion, Emend oral capsules may be dispensed by a retail pharmacy. Your Doctor will decide the best way to give Emend based upon the chemo regimen you are receiving.

Side Effects

What are the most common side effects from fosaprepitant?

In the prescribing label information (fosaprepitant package insert), the most commonly reported side effects from fosaprepitant (Emend®) are shown here:

  • Fatigue (15%)
  • Diarrhea (13%)
  • Low white blood cells (8%)
  • Weakness (4%)
  • Low red blood cells [anemia] (3%)
  • Pins and needles feeling in finger or toes (3%)
  • Heartburn (2%)
  • Urinary tract infection (2%)
  • Pain in arms or legs (2%)
  • Infusion site reactions (2%)

Note: The exact percentages of patients that will experience fosaprepitant side effects is unknown because it has been used under widely varying patient populations in a variety of clinical trials.

Fosaprepitant should be used in pregnant women only if the potential benefits to the mother outweigh the potential risks to the unborn baby.

Watch videos on common fosaprepitant therapy side effects below

Side effect videos Side Effect Videos
Fatigue Fatigue DiarrheaDiarrheaAnemiaAnemiaPainPain


How often is fosaprepitant (Emend) monitoring needed?

Labs (blood tests) typically do not need to be monitored for fosaprepitant, but may be checked before each chemotherapy treatment.

How often is imaging needed?

Imaging is not usually necessary to start or continue fosaprepitant therapy.

How might Emend blood test results/imaging affect treatment?

Depending upon the results, your doctor may advise to continue fosaprepitant as planned or switch to an alternative therapy.

Questions to Ask Your...

A better understanding of your treatments will allow you to ask more questions of your healthcare team. We then hope that with the answers, you will get better results and have greater satisfaction with your care. Because we know it's not always easy to know what questions to ask, we've tried to make it easy for you!

Choose any healthcare provider below to see common questions that you may want to ask of this person. Then, either print each list to bring to your clinic visits, or copy the questions and send them as a message to your healthcare team through your electronic medical record.

ChemoExperts Tips

What are the most important things to know about fosaprepitant (Emend®) while receiving therapy?

  • If you are receiving warfarin, fosaprepitant may cause a decrease in your INR and your dose of warfarin may need to be adjusted
  • Fosaprepitant may decrease efficacy of oral contraceptives. Use an alternative method of contraception during treatment and for one month following the last dose of fosaprepitant
  • May interact with certain antifungal and seizure medications. Ask your doctor or pharmacist to review your medications for any possible interactions
  • Avoid therapy with St. Johns Wort as it will decrease blood levels of fosaprepitant. This could decrease the effectiveness of fosaprepitant
  • A pharmacist should ALWAYS review your medication list to ensure that drug interactions are prevented or managed appropriately

Patient Assistance & Co-payment Coverage

Patients under the age of 65 years, or those with private insurance plans:
If you have insurance and are looking for patient assistance or copay assistance for Fosaprepitant (Emend®), we have provided links that may help.

Visit our Patient Assistance page and click the links to various patient assistance programs for help paying for Fosaprepitant (Emend®). Depending upon your income, they may be able to help cover the cost of:

  • Fosaprepitant (Emend®)

For Branded medications (may be available for generic medications too), check with the manufacturer to determine if a co-pay card is offered and if it could reduce your monthly copay.

  • If you are uninsured, check with the manufacturer to determine if you are eligible to receive medication at no cost.

Medicare and Medicaid patients (Patients 65 years or older):
The clinic providing treatment will likely pre-authorize medications and immune therapies such as Fosaprepitant (Emend®) and are the best source to help you understand drug cost.

  • Ask to speak with a patient assistance technician or financial counselor at the clinic or hospital administering this therapy.

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Created: April 1, 2020 Updated: April 17, 2020

What is Nausea and Vomiting?

Nausea is the sensation that there is a need to vomit. Nausea can be acute and short-lived, or it can be prolonged. When prolonged, it is a debilitating symptom. Nausea (and vomiting) can be psychological or physical in origin.

NOTE: Treatment Options listed below are not all-inclusive. Other treatments may be available. ChemoExperts provides drug information and does not recommend any one treatment over another. Only your Doctor can choose which therapy is appropriate for you.