Description and Brand Names

Drug information provided by: Micromedex

US Brand Name

  1. Emend


Fosaprepitant injection is used with other medicines to prevent nausea and vomiting caused by cancer treatment (chemotherapy). It acts in the brain to prevent nausea.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

  • Powder for Solution

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of fosaprepitant injection in the pediatric population. Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of fosaprepitant injection in the elderly. However, elderly patients are more likely to have liver, kidney, or heart problems, which may require caution in patients receiving this medicine.


There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Flibanserin
  • Lomitapide
  • Pimozide

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Atazanavir
  • Boceprevir
  • Bosutinib
  • Brexpiprazole
  • Carbamazepine
  • Ceritinib
  • Cilostazol
  • Clarithromycin
  • Clozapine
  • Cobicistat
  • Cobimetinib
  • Colchicine
  • Conivaptan
  • Dasatinib
  • Diltiazem
  • Docetaxel
  • Domperidone
  • Doxorubicin
  • Doxorubicin Hydrochloride Liposome
  • Dronedarone
  • Enzalutamide
  • Eplerenone
  • Erythromycin
  • Fentanyl
  • Fluconazole
  • Fosphenytoin
  • Hydrocodone
  • Ibrutinib
  • Idelalisib
  • Ifosfamide
  • Imatinib
  • Indinavir
  • Itraconazole
  • Ivabradine
  • Ivacaftor
  • Ketoconazole
  • Lopinavir
  • Lumacaftor
  • Lurasidone
  • Mitotane
  • Naloxegol
  • Nefazodone
  • Nelfinavir
  • Olaparib
  • Oxycodone
  • Phenytoin
  • Piperaquine
  • Posaconazole
  • Ranolazine
  • Rifampin
  • Ritonavir
  • Saquinavir
  • Simeprevir
  • Sonidegib
  • St John's Wort
  • Tacrolimus
  • Telaprevir
  • Telithromycin
  • Tolvaptan
  • Venetoclax
  • Verapamil
  • Voriconazole

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Desogestrel
  • Dexamethasone
  • Dienogest
  • Drospirenone
  • Estradiol Cypionate
  • Estradiol Valerate
  • Ethinyl Estradiol
  • Ethynodiol Diacetate
  • Etonogestrel
  • Levonorgestrel
  • Medroxyprogesterone Acetate
  • Mestranol
  • Midazolam
  • Norelgestromin
  • Norethindrone
  • Norgestimate
  • Norgestrel
  • Quetiapine
  • Suvorexant

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Proper Use

A nurse or other trained health professional will give you this medicine in a hospital or clinic. This medicine is given through a needle placed in one of your veins. The infusion may take up to 30 minutes.

This medicine is usually given on the first day of your chemotherapy along with other medicines. Fosaprepitant is not for long-term use, but you may need to use this medicine again if you have more chemotherapy in the future.

This medicine comes with a patient information insert. It is very important that you read and understand this information. Be sure to ask your doctor about anything you do not understand.


It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly and to check for unwanted effects.

You should not receive this medicine if you are also using pimozide (Orap®). Fosaprepitant may cause serious or life-threatening problems if used together with this medicine.

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Tell your doctor or nurse right away if you have itching, hives, a rash, trouble breathing, trouble swallowing, warmth or redness in your face, neck, arms, or upper chest, or any swelling of your hands, face, or mouth while you are receiving this medicine.

If you are also using a blood thinner called warfarin (Coumadin®, Jantoven®), your doctor will need to check your blood after using this medicine.

Birth control pills may not work as well while you are using fosaprepitant. To keep from getting pregnant, use another form of birth control together with your pills during treatment and for one month after your last treatment. Other forms include condoms, a diaphragm, and contraceptive foam or jelly.

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

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

More common

  1. Black, tarry stools
  2. blurred vision
  3. chills
  4. confusion
  5. cough
  6. decreased urination
  7. difficult or labored breathing
  8. dizziness
  9. dry mouth
  10. fainting
  11. fever
  12. increase in heart rate
  13. lightheadedness
  14. lower back or side pain
  15. nervousness
  16. pain, swelling, or redness at the injection site
  17. painful or difficult urination
  18. pale skin
  19. pounding in the ears
  20. rapid breathing
  21. slow or fast heartbeat
  22. sore throat
  23. sunken eyes
  24. tenderness, swelling, warmth, or skin discoloration at the injection site
  25. thirst
  26. tightness in the chest
  27. ulcers, sores, or white spots in the mouth
  28. unusual bleeding or bruising
  29. unusual tiredness or weakness
  30. wrinkled skin

Less common

  1. Hard lump at the injection site


  1. Blood in the urine
  2. changes in patterns and rhythms of speech
  3. changes in skin color
  4. chest pain or discomfort
  5. coma
  6. convulsions
  7. fast, slow, irregular, pounding, or racing heartbeat or pulse
  8. general feeling of discomfort or illness
  9. headache
  10. increased sweating
  11. increased thirst
  12. lightheadedness, dizziness, or fainting
  13. muscle pain or cramps
  14. nausea or vomiting
  15. pain, tenderness, or swelling of the foot or leg
  16. slurred speech
  17. swelling
  18. swelling of the face, ankles, or hands
  19. trouble with speaking
  20. troubled breathing with exertion

Incidence not known

  1. Difficulty with swallowing
  2. hives or welts, itching
  3. large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  4. puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  5. redness of the skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Acid or sour stomach
  2. belching
  3. burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  4. continuing ringing or buzzing or other unexplained noise in ears
  5. diarrhea
  6. difficulty having a bowel movement (stool)
  7. dizziness
  8. feeling of indigestion
  9. hair loss or thinning of the hair
  10. hearing loss
  11. hiccups
  12. indigestion
  13. lack or loss of strength
  14. loss of appetite
  15. pain in the chest below the breastbone
  16. stomach discomfort, upset, or pain
  17. swelling or inflammation of the mouth
  18. weight loss

Less common

  1. Feeling of warmth
  2. pain or discomfort in chest, upper stomach, or throat
  3. redness of the face, neck, arms, and occasionally, upper chest
  4. sudden sweating
  5. unusually warm skin


  1. Abdominal or stomach distension or pain
  2. abnormal dreams
  3. blemishes on the skin
  4. bumps on the skin
  5. burning, dry, or itching eyes
  6. change in taste
  7. change in walking and balance
  8. clumsiness or unsteadiness
  9. confusion about identity, place, and time
  10. difficulty with moving
  11. discharge, excessive tearing
  12. excess air or gas in the stomach
  13. extreme thirst
  14. false or unusual sense of well-being
  15. flushed, dry skin
  16. frequent urination
  17. fruit-like breath odor
  18. full feeling
  19. heartburn
  20. increased hunger
  21. increased sensitivity of the skin to sunlight
  22. increased urination
  23. increased volume of pale, dilute urine
  24. joint pain
  25. muscle aching or cramping
  26. muscle stiffness or weakness
  27. oily skin
  28. passing gas
  29. pimples
  30. redness or other discoloration of the skin
  31. redness, pain, or swelling of the eye, eyelid, or inner lining of the eyelid
  32. severe constipation
  33. severe sunburn
  34. sleepiness
  35. sweating
  36. swollen joints
  37. trouble performing routine tasks
  38. trouble sleeping
  39. unexplained weight loss
  40. unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  41. weight gain
  42. white patches in the mouth or throat or on the tongue
  43. white patches with diaper rash

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.