Fosaprepitant (Intravenous)

Fosaprepitant helps to reduce nausea and vomiting experienced by patients after some chemotherapy medications. It is used along with other drugs for best results.


Fosaprepitant helps in reducing nausea and vomiting experienced by patients after some chemotherapy medications. It acts in the brain by blocking neurokinin which causes vomiting. For better results, it is used along with other drugs. Fosaprepitant interacts with other medicines like Pimozide (Orap) making it less efficient hence it's essential for the doctor to know the medications that the patient is currently taking. The injection can cause severe allergic reactions like Anaphylaxis which requires immediate medical help. It is, however, a useful injection that should only be administered in the hospital or a clinical setup by a professional health practitioner.

Conditions Treated

  • Nausea
  • Vomiting

Type Of Medicine

  • Antiemetic

Side Effects

Alongside the needed effects, Fosaprepitant injection may cause unwanted effects. The most common effects are blurred vision, confusion, tarry stools, decreased urination, cough, dry mouth, and dizziness, redness at the injection spot, fever, increased heartbeat, lower back pain, and nervousness. Some patients have also reported painful urination, sore throat, sunken eyes, pale skin, thirst, chest tightness, unusual bleeding, wrinkled skin and mouth ulcers. It's advisable to inform the doctor if the symptoms become severe.

Fosaprepitant also causes other serious side effects although their occurrence is sporadic. For example, the patient may experience coma, convulsions, urine with blood clots, skin discoloration, changes in speech rhythms and patterns, cramps or muscle pains, increased sweating, swollen face and ankles as well as slurred speech.

Not all the side effects require medical attention as most of them go away with time as the body continues to adjust to the treatment. The effects may also be severe in some patients than others. Your doctor may even give you some tips on what to do to reduce the side effects. It's, however, recommendable to check with your medical practitioner if the symptoms persist or in case you have questions about them.

Fosaprepitant has other minor side effects which may happen for a short period. Belching, sour or acid stomach, diarrhea, buzzing and ringing noise in the ears, hiccups, indigestion, dizziness, feeling an excess warmth, stomach upsets and discomfort, loss of appetite, and mouth inflammation are some of them. The doctor gives advice on how to take care of the injection site in case it develops erythema, thrombophlebitis, rashes, edema, and hives.

The patient should seek immediate help if some symptoms like skin bumps, abdominal pains, skin blemishes, change in taste, clumsiness, as well as identity, time and place confusion, continue for some days. Other acute effects that should not be ignored are fruit like odor when breathing, extreme thirst, excess stomach gas, moving difficulty, increased sensitivity to sunlight, increased hunger, muscle cramping and aching, increased pale urine, oily skin and joint pains. Some patients may experience abnormal weight gain after the injection. In this case, the doctor may choose to stop the medication on the patient altogether.
There are other adverse effects not mentioned here that may occur. Always check with your doctor for more clarification and close monitoring. You can also report the side reactions to FDA at 1-800-FDA-1088.


A professional health provider is the only one who should give Fosaprepitant. It is designed to prevent the delayed acute nausea and vomiting that comes after a High Emetogenic Cancer therapy (HEC) or due to the Moderate Emetogenic Cancer therapy (MEC). It is administered into the veins through IV. It is used by combining it with other antiemetic medicines. The infusion is usually given 30 minutes before the chemotherapy starts. Before the administration, the injection needs first to be well prepared. The following instructions are followed:

Step 1: Inject aseptically 5ml of 0.9% sodium chloride solution. Add USP to the vial to prevent foaming. Swirl the solution gently. Avoid jetting and shaking 0.9% sodium chloride infusion, USP in the jar.

Step 2: prepare infusion bag aseptically and fill it with 145ml of 0.9% sodium chloride infusion, USP.

Step 3: withdraw the solution aseptically from the vial then transfer it into the infusion bag with 145 ml of 0.9% sodium chloride. The USP should yield to a 150ml total volume and the final concentration 1mg/ml.

Step 4: invert the bag gently 2 to 3 times. Before administering the medicine, inspect the bag for any discoloration or particulate matter observed.

Avoid mixing or reconstituting the EMEND for infusion with solutions because the chemical and physical compatibility has not yet been established. EMEND used for injection is incompatible with the solutions that contain divalent cations like Ca2+, Mg2+), including the Hartmann's solution and the Lactated Ringer's Solution.

For the High Emetogenic Chemotherapy, injections are done as follows.

Day 1: 150 mg IV is infused for over 20-30 minutes 'done 30 minutes before the chemotherapy. Dexamethasone 12 mg PO and a 5-HT3 antagonist.

Day 2: Infuse Dexamethasone 8 mg PO in AM

Days 3 and 4: Infuse Dexamethasone 8 mg PO BID both in the morning and evening
Note that: it is recommendable to reduce the Dexamethasone on the first and second day to account for a possible reaction with aprepitant.

For Moderate Emetogenic Chemotherapy, the injections are done as follows:

Day 1: infuse 150 mg IV for 20-30 minutes. This should be done 30 minutes before chemotherapy. Dexamethasone 12 mg PO and a 5-HT3 antagonist

Days 2-3: Infuse 80 mg PO at least 1 hour before the chemotherapy
Note that: the Dexamethasone dosage may be reduced by 50% in the first and second day to a possible reaction with the Fosaprepitant.

The same adult dosage can be administered without adjustments to the elderly (Adults above 65 years), renal impaired patients and the patients with hepatic impairment. The safety of the injection to children below the age of 18 has not yet been established. The drug's effect on pregnancy has not been confirmed, but it is assumed not to be dangerous to the unborn babies. It's however important to let the health provider know if you are pregnant. The same applies to breastfeeding; the patient should tell the doctor if she is breastfeeding.

Overdosage does not have any specific treatment. Due to the antiemetic nature of the injection, drug-induced emesis cannot be useful for the overdosage. In case it happens the patient can be subjected to close monitoring.


It is essential for a patient to have a record of all the drugs he/ she is currently taking. This is because some medications interact in the body with some causing dangerous reactions. Although not all medicines work well once used with others, there are some that can be used together if an interaction occurs. In those cases, it might be necessary to take other precautionary measures. Your doctor may also change the dose for the patient.

Once Fosaprepitant injection is administered, an aprepitant product is changed into aprepitant within in 30 minutes time. Therefore, most of the drug interactions that occur after the intravenous administration are mostly the medications that interact with the oral aprepitant.

Before you receive the treatment, inform your health provider if you are currently taking any of the listed below medicines. It is not advisable to take Fosaprepitant injection if you are using any of them. Your doctor may either change the drugs you are taking or decide not to inject with Fosaprepitant.

  • Flibanserin
  • Pimozide
  • Lomitapide

It is also not recommendable to use this drug with Lurasidone although it might be necessary sometimes. If both drugs are prescribed at the same time, your doctor may change their dosage and frequency intake. Also, taking Fosaprepitant together with Dienogest, Estradiol Cypionate, Ethinyl, Levonorgestrel, Medroxyprogesterone Acetate, Norethindrone, Norgestimate and Quetiapine may increase the chance of getting adverse effects. Your doctor may decide to reduce or completely change their intake frequency in order to reduce the negative effects.

Most medicines do not work well when taken together with certain foods and drinks. Using tobacco and alcohol can cause interactions. Discuss with your doctor on the menu that may affect the effectiveness of Fosaprepitant.


Before you use Fosaprepitant injection, inform the doctor if you are allergic to the medicine, aprepitant (Emend), any Fosaprepitant ingredients or other medications. You can ask the doctor to tell the Fosaprepitant ingredients. You should also not be given this drug if are using Pimozide (Orap). Pimozide has a high plasma concentration. Severe and life-threatening effects may be triggered by the combination of these two drugs. Use of Fosaprepitant with the active and moderate CYP3A4 inhibitors like Ketoconazole also increases the concentration of plasma, and this may lead to adverse reactions.

Fosaprepitant can sometimes cause severe allergic reactions like Anaphylaxis. This response needs immediate medical attention. Inform your doctor right away when you start experiencing hives, rashes, itching. Trouble swallowing and breathing, warmth in your face, or swelling in any of your body parts especially the face and arms. These could be Anaphylaxis symptoms.

Inform the doctor if you have any liver disease. Also, your doctor may have to test your blood if you are currently using a blood thinner known as Warfarin. Tell the doctor of the prescribed and non prescribed drugs medicines, nutritional supplements, vitamins and herbal drugs that you are taking. Be sure to disclose certain antifungal like Itraconazole (Sporanox), cancer chemotherapy medications like Ifosfamide (Ifex), HIV protease inhibitors like Nelfinavir (Viracept) and any hormonal contraceptive.

The birth control pills do not work well on patients who use Fosaprepitant. It sometimes takes up to 28 days since the last Fosaprepitant injection for the hormonal contraceptive to become effective. It might, therefore, be necessary for the patient to use other birth control methods since the effectiveness of the pills may be reduced. The best alternatives birth control measures to use during this time are condoms, contraceptives foams, and diaphragms. Also, let the doctor know if are pregnant or you are planning to become pregnant. The doctor will decide while administering the drug.

Avoid taking other medicines before you consult your doctor. It is imperative for the doctor to monitor your progress at regular basis to ensure that the drug is working well for you.


Fosaprepitant injection should be refrigerated at 2°C-8°C (36°F-46°F). The medicine is however stored in hospital hence not applicable for home storage.


Fosaprepitant is a useful antiemetic that helps in reducing chemotherapy-induced nausea and vomiting. It is used with other drugs to block the substances that trigger vomiting in patients once they undergo the chemotherapy. It is administered into the body through an injection made into the veins 30 minutes before the chemotherapy.

Just like the other medications Fosaprepitant injection has some side effects like diarrhea and dizziness. They, however, go away after a short period. The patient is put under close supervision to ensure the side effects do not persist. In case the implications become bothersome while the patient is away from the hospital, immediate medical attention should be sought.

Fosaprepitant interacts with other drugs like Flibanserin, Pimozide, and Lomitapide. These interactions may reduce the effectiveness of the drug hence it's advisable to notify the doctor the medicines that you are taking. It's also good to let the doctor know if you have had any liver disease before. Keeping a record of the drugs you are currently taking helps the health practitioner to determine if you will drop some or not.

As much as this drug is essential to the cancer patients, it sometimes causes allergic reactions like Anaphylaxis. It also reduces the effectiveness of the birth control pills. A patient who is administered this medicine every time during the chemotherapy sessions should consider using other methods of birth control. The safety of the drug to the expectant and breastfeeding mothers has not yet been determined, but it's essential to inform the doctor before the injection.