Aprepitant is used together with other medications to prevent nausea and vomiting that may be caused by chemotherapy.

Aprepitant is given ahead of time and will not treat nausea or vomiting that you already have.

Aprepitant capsules are for use in adults and children who are at least 12 years old. Aprepitant oral suspension (liquid) can be given to adults and children as young as 6 months old.

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

You should not use aprepitant if you are allergic to it, or if you use another medicine called pimozide. Aprepitant can cause unwanted or dangerous side effects when used with pimozide.

Tell your doctor if you have ever had:

• liver disease.

Tell your doctor if you are pregnant or breastfeeding. You should not be treated with aprepitant injection if you are pregnant.

Aprepitant can make hormonal birth control less effective, including birth control pills, injections, implants, skin patches, and vaginal rings. To prevent pregnancy while using aprepitant, use a barrier form of birth control: condom, diaphragm, cervical cap, or contraceptive sponge.

Keep using the barrier form of birth control for 1 month after your last dose of aprepitant.

Use Emend 2-Day (Oral) 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, itching, difficult breathing, dizziness, trouble swallowing, fast heartbeat, wheezing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Call your doctor at once if you have:

• a light-headed feeling, like you might pass out;
• pain or burning when you urinate;
• sores or white patches in your mouth or throat, sore throat;
• low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath; or
• dehydration symptoms--feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin.

Common side effects may include:

• stomach pain, indigestion, burping, loss of appetite;
• low blood cell counts;
• diarrhea, constipation;
• hiccups;
• abnormal liver function tests;
• headache, dizziness;
• dehydration;
• pain in your arms or legs;
• pain, hardening, redness, swelling, or itching where the medicine was injected;
• cough; or
• feeling weak or tired.

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.