Fosaprepitant is used together with other medications to prevent nausea and vomiting that may be caused by chemotherapy in adults and children at least 6 months old who weigh at least 6 kg (13 pounds).

Fosaprepitant is not used to treat nausea and vomiting that you already have.

Fosaprepitant may also be used for purposes not listed in this medication guide.

You should not use this medicine if you are allergic to fosaprepitant or similar medicines such as aprepitant.

Some drugs should not be used with fosaprepitant. Your treatment plan may change if you also use pimozide.

Tell your doctor if you have ever had:

• to use a blood thinner (or a medicine called warfarin) and you have routine "INR" or prothrombin time tests; or
• liver disease.

It is not known if fosaprepitant will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Ask a doctor if it is safe to breastfeed while using this medicine.

Fosaprepitant can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. Use barrier birth control to prevent pregnancy: condom, diaphragm, cervical cap, or contraceptive sponge.

Ask your doctor about the best form of birth control while you are using fosaprepitant. Keep using the barrier form of birth control for 1 month after your last dose.

Use Focinvez (Intravenous) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Some side effects may occur during the injection. Tell your medical caregiver if you feel dizzy, nauseated, light-headed, itchy, sweaty, or have a headache, chest tightness, back pain, trouble breathing, or swelling in your face.

Call your doctor at once if you have:

• pain, redness, swelling, burning, blistering, or skin changes where the medicine was injected; or
• a light-headed feeling, like you might pass out; or
• fast or slow heart rate.

Common side effects may include:

• feeling weak or tired;
• fever;
• low blood cell counts;
• urinary tract infection;
• stomach pain or upset;
• diarrhea; or
• pain, weakness, or numbness in your arms or legs.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.