Emend (Aprepitant) – Oral

What is Emend?

Emend (Aprepitant) is a medicine that helps prevent nausea and vomiting after chemotherapy (a cancer treatment) or surgery. It belongs to a class of drugs called P/neurokinin-1 (NK1) receptor antagonists, which block the effects of chemicals in the nervous system that cause vomiting.

You can take Emend by mouth as a capsule or as a solution (liquid), but it can also be given as an infusion. This article will focus on Emend’s oral form.

Drug Facts

Generic Name: Aprepitant

Brand Name: Emend

Route of Administration: Oral

Drug Availability: Prescription

Treatment Category: Antiemetics

Generally available: yes

Controlled Substances: Not applicable

Active ingredient: Aprepitant

Dosage form: capsule, powder suspension

What is Emend for?

The U.S. Food and Drug Administration (FDA) approves Emend for use with other anti-nausea or antiemetic drugs to prevent chemotherapy-induced nausea.

Some chemotherapy drugs can cause severe nausea. This can happen right after chemotherapy or a few days later. Some other anti-nausea medications help relieve nausea. However, Emend helps prevent this nausea before it happens.

Emend also prevents nausea and vomiting after surgery in adults.

The oral suspension version of Emend is approved for use in people 6 months and older, and the capsule form is for people 12 years and older.

How to take Emend

When prescribing Emend, follow your healthcare provider’s instructions on when and how to take it. Dosage instructions may vary slightly based on your chemotherapy plan.

However, you will usually take Emend an hour before your first day of chemotherapy. On the second and third days, if receiving chemotherapy on those days, take it in the morning or an hour before chemotherapy. You can take Emend with or without food.

Make sure to swallow the capsules whole – do not break or crush them. Your healthcare provider can prescribe Emend in liquid form for you if you have trouble swallowing the capsules.

You will also take other anti-nausea medications with Emend to help it work best. These drugs include a steroid called dexamethasone and a class of 5-HT3 antagonists. Your healthcare team will instruct you on how to take these medicines.


Store Emend capsules in their original packaging at room temperature. The liquid form of Emend should be stored in the refrigerator.

How long does it take for Emend to go to work?

Once taken, Emend works quickly to prevent nausea. It is most effective when you take it for three days as directed and with other prescription medicines.

What are the side effects of Emend?

This is not a complete list of side effects, other side effects may occur. A medical professional can advise you about side effects. If you experience other effects, please contact your pharmacist or medical professional. You can report side effects to the FDA at www.fda.gov/medwatch or at 800-FDA-1088.

Side effects may occur while taking Emend. It’s important to remember that these are possible side effects, not a list of things that are certain to happen. Be sure to tell your healthcare provider of any persistent or worsening side effects.

common side effects

Common side effects include:

  • tired
  • diarrhea
  • hiccup
  • Leukopenia
  • weakness or lack of energy
  • stomachache
  • Elevated liver enzymes

serious side effects

In rare cases, Stevens-Johnson syndrome may occur after taking Emend. Stevens-Johnson syndrome is a severe skin reaction that includes symptoms such as a severe rash, burning, or itching. If you start to experience these symptoms, stop taking Emend and contact your healthcare provider.

report side effects

Emend may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience serious side effects, you or your provider can send a report to the FDA’s MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

(800) 332-1088

Dosage: How much Emend should I take?

Drug content provided and reviewed

IBM Micromedicine®

The dose of this medicine will vary for different patients. Follow your doctor’s order or directions on the label. The information below includes only the average dose of this medicine. If your dose is different, do not change it unless your doctor tells you to.

The amount of medicine you take depends on the strength of the medicine. In addition, the dose you take each day, the time allowed between doses, and the length of time you take the medication depend on the medical problem for which you are using the medication.

  • For oral dosage form (capsules):

    • To prevent nausea and vomiting from chemotherapy:

      • Adults and children 12 years and older – 125 milligrams (mg) 1 hour before chemotherapy (Day 1). Then, take 80 mg once in the morning on days 2 and 3.
      • Children under 12 who weigh at least 30 kilograms (kg) can swallow the 125 mg capsule 1 hour before chemotherapy (Day 1). Then, take 80 mg once in the morning on days 2 and 3.
      • Children under 12 years weighing less than 30 kg – use and dosage must be determined by your doctor.
    • To prevent nausea and vomiting after surgery:

      • Adults – 40 milligrams (mg) within 3 hours before surgery.
      • Children – use and dosage must be determined by your doctor.
  • For oral dosage form (powder for suspension):

    • To prevent nausea and vomiting from chemotherapy:

      • Adults and children 6 months to 11 years who cannot swallow capsules – the dose is based on weight and must be determined by your doctor. The dose is usually 3 milligrams (mg) per kilogram (kg) of body weight, with a maximum dose of 125 mg taken 1 hour before chemotherapy (Day 1). Then, take 2 mg/kg body weight once in the morning on Days 2 and 3, up to a maximum dose of 80 mg.
      • Children under 6 months – use and dosage must be determined by your doctor.

missed dose

If you miss a dose of Emend, take it as soon as you remember, as long as you haven’t had time to take your next dose. If you miss a dose entirely, please contact your healthcare team.

Overdose: What will happen if I take too much Emend?

If you take too much Emend, contact your healthcare provider to let them know. An overdose can cause headaches and drowsiness. However, there have been no reported cases of serious effects resulting from overdose of Emend.

What will happen if I overdose on Emend?

If you think you or someone else may have overdose on Emend (aprepitant), call your healthcare provider or poison control center (800-222-1222).

If anyone passes out or is not breathing after taking Emend, call 911 right away.



Drug content provided and reviewed

IBM Micromedicine®

It is very important for your doctor to check your progress while you are using this medicine to make sure it’s working properly and check for ill effects.

Do not use this medicine if you are also using pimozide (Orap®). Using these drugs together may cause serious adverse side effects.

This medicine may cause a serious allergic reaction, including anaphylaxis. Allergic reactions can be life-threatening and require immediate medical attention. Call your doctor right away if you develop itching, hives, rash, trouble breathing, trouble swallowing, or swelling of your hands, face, or mouth while using this medicine.

Birth control pills may not work as well when you are using aprepitant. To avoid pregnancy, use another form of birth control and the pill while you are using this medicine and for 1 month after your last dose. Other forms of birth control include condoms, diaphragms, or birth control foam or jelly.

Do not take other medicines unless discussed with your doctor. This includes prescription or over-the-counter (OTC) medicines [OTC]) medicines and herbal or vitamin supplements.

Why should I not take Emend?

Do not take if you are allergic to Emend or any of its ingredients.

Tell your healthcare provider if you are pregnant, planning to become pregnant, or breastfeeding. There is not enough data to know the risks to the baby of taking Emend during pregnancy or breastfeeding.

What other drugs interact with Emend?

Certain medicines can interact with Emend when taken together.

Emend can reduce the effects of hormonal birth control pills for up to 28 days after you take your last dose of Emend. If you take birth control pills, use backup birth control pills during this time.

Another interaction is with the drug coumarin (warfarin). Emend can reduce the effects of coumarin. Your healthcare provider may adjust your coumarin dose.

You also shouldn’t take Emend with an antipsychotic drug called Orap (pimozide) because it can cause potentially life-threatening heart problems.

Taking Emend with the following medicines may also require a dose change:

  • Medrol (Methylprednisolone)
  • Cardizem CD (diltiazem)
  • Nizoral (ketoconazole)
  • Biahin (clarithromycin)
  • Sporanox (itraconazole)
  • rifadine (rifampicin)
  • Tegretol (carbamazepine)
  • Dilantine (phenytoin)

What are similar drugs?

In addition to Emend, there are other drugs in the same class that can prevent nausea and vomiting from chemotherapy.

These drugs include:

  • Akynzeo (netupitant/palonosetron)
  • Emend (fosaprepitant, Emend’s injection)

These medicines cannot be taken together.

Frequently Asked Questions

  • What is Emend for?

    Emend is used to prevent immediate and delayed nausea and vomiting caused by chemotherapy. It also prevents nausea and vomiting that can occur after surgery.

  • How does Emend work?

    Emend works by blocking certain substances in the brain called neurokinins, which cause nausea and vomiting. Emend is given before chemotherapy to prevent nausea and vomiting. It does not apply to nausea or vomiting that has already occurred.

  • Which medicines should not be taken with Emend?

    You should not take an antipsychotic drug called Orap (pimozide) with Emend because this can cause life-threatening heart problems. Other drug interactions include hormonal contraception and warfarin.

  • What are the side effects of Emend?

    Side effects of Emend may include:

    • fatigue
    • weakness or lack of energy
    • diarrhea
    • Leukopenia
    • hiccup
    • stomachache
    • Elevated liver enzymes

How can I stay healthy while taking Emend?

Nausea and vomiting from chemotherapy can be a very distressing side effect that can lead to malnutrition and dehydration.

Taking Emend as prescribed, along with other medicines, can prevent severe nausea and vomiting from chemotherapy. Lifestyle factors, such as good nutrition, may also help ease chemotherapy-related side effects.

Alternative methods of relieving nausea may help, but should be used in conjunction with, not in place of, anti-nausea medication.

Be sure to ask your oncology care team if you have any questions about taking this drug.

Medical Disclaimer

VigorTip Health’s drug information is for educational purposes only and is not a substitute for medical advice, diagnosis or treatment by a healthcare professional. Consult your doctor before taking any new medicines. IBM Watson Micromedex provides some drug content as shown on the page.