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Emend for Injection Side Effects

Generic name: fosaprepitant

Medically reviewed by Last updated on Jul 30, 2023.

Note: This document contains side effect information about fosaprepitant. Some dosage forms listed on this page may not apply to the brand name Emend for Injection.

Applies to fosaprepitant: intravenous powder for solution.

Serious side effects of Emend for Injection

Along with its needed effects, fosaprepitant (the active ingredient contained in Emend for Injection) 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 while taking fosaprepitant:

More common

Less common


Incidence not known

Other side effects of Emend for Injection

Some side effects of fosaprepitant 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

Less common


For Healthcare Professionals

Applies to fosaprepitant: intravenous powder for injection, intravenous solution.


The most common side effects reported were fatigue, diarrhea, neutropenia, asthenia, anemia, peripheral neuropathy, leukopenia, dyspepsia, urinary tract infection, and pain in extremity.

Because fosaprepitant (the active ingredient contained in Emend for Injection) is converted to aprepitant, side effects associated with aprepitant may be expected to occur with this drug. The manufacturer product information for aprepitant should be consulted.[Ref]


Uncommon (0.1% to 1%): Increased blood pressure, flushing, hot flush, palpitations, thrombophlebitis

Frequency not reported: Hypotension


-Uncommon (0.1% to 1%): Palpitations, hot flush/flushing

-Rare (0.01% to 0.1%): Bradycardia, cardiovascular disorder


Uncommon (0.1% to 1%): Erythema

Postmarketing reports: Pruritus, rash, urticaria, Stevens-Johnson syndrome/toxic epidermal necrolysis


-Uncommon (0.1% to 1%): Acne, rash

-Rare (0.01% to 0.1%): Hyperhidrosis, photosensitivity reaction, pruritic rash, seborrhea, skin lesion, Stevens-Johnson syndrome/toxic epidermal necrolysis

-Frequency not reported: Pruritus, urticaria, angioedema


Constipation and subileus occurred at higher doses of aprepitant.

Very common (10% or more): Diarrhea (up to 13%)

Common (1% to 10%): Constipation, dyspepsia

Uncommon (0.1% to 1%): Abdominal distention, abdominal pain, upper abdominal pain, oral candidiasis


-Common (1% to 10%): Constipation, dyspepsia, diarrhea, eructation

-Uncommon (0.1% to 1%): Abdominal pain, gastroesophageal reflux disease, nausea, vomiting, dry mouth, flatulence

-Rare (0.01% to 0.1%): Duodenal ulcer perforation, abdominal distension, hard feces, neutropenic colitis, stomatitis

-Frequency not reported: Upper abdominal pain, abnormal bowel sounds, stomach discomfort, subileus


Common (1% to 10%): Urinary tract infection


-Uncommon (0.1% to 1%): Dysuria

-Rare (0.01% to 0.1%): Glucose urine present, pollakiuria, RBCs urine positive, increased urine output


Common (1% to 10%): Anemia, leukopenia, neutropenia

Frequency not reported: Thrombocytopenia


-Common (1% to 10%): Decreased hemoglobin

-Uncommon (0.1% to 1%): Febrile neutropenia, anemia

-Rare (0.01% to 0.1%): Decreased neutrophil count



-Common (1% to 10%): Increased ALT, increased AST

-Frequency not reported: Increased blood bilirubin


Frequency not reported: Immediate hypersensitivity reactions (including flushing, erythema, dyspnea, anaphylactic reactions/anaphylactic shock)

Postmarketing reports: Hypersensitivity reactions (including anaphylactic reactions/anaphylaxis, anaphylactic shock), immediate hypersensitivity/anaphylactic reactions during infusion (including flushing, erythema, rash, chest tightness, wheezing, dyspnea)


Infusion site reactions occurred in 2.2% of patients treated with this drug compared to 0.6% of patients treated with ondansetron and dexamethasone (standard therapy). These reactions included infusion-site pain, injection-site irritation, vessel puncture-site pain, and infusion-site thrombophlebitis.

Common (1% to 10%): Infusion-site reactions, infusion site pain

Uncommon (0.1% to 1%): Infusion-site erythema, infusion-site induration, infusion-site pruritus, infusion-site thrombophlebitis, injection-site irritation, vessel puncture-site pain


Uncommon (0.1% to 1%): Decreased appetite


-Common (1% to 10%): Decreased appetite

-Rare (0.01% to 0.1%): Polydipsia

-Frequency not reported: Increased blood glucose


Common (1% to 10%): Pain in extremity


-Rare (0.01% to 0.1%) Muscular weakness, muscle spasms

Nervous system

Ifosfamide-induced neurotoxicity has been reported after coadministration of this drug and ifosfamide.

Common (1% to 10%): Peripheral neuropathy

Frequency not reported: Syncope

Postmarketing reports: Ifosfamide-induced neurotoxicity


-Common (1% to 10%): Headache

-Uncommon (0.1% to 1%): Dizziness, somnolence

-Rare (0.01% to 0.1%): Cognitive disorder, dysgeusia, lethargy, tinnitus

-Frequency not reported: Dysarthria, hypoesthesia, sensory disturbance



-Rare (0.01% to 0.1%): Conjunctivitis

-Frequency not reported: Miosis, reduced visual acuity


Very common (10% or more): Fatigue (up to 15%)

Common (1% to 10%): Asthenia


-Common (1% to 10%): Asthenia, fatigue

-Uncommon (0.1% to 1%): Malaise, increased blood alkaline phosphatase

-Rare (0.01% to 0.1%): Candidiasis, staphylococcal infection, gait disturbance, decreased blood sodium, weight decreased, chest discomfort, edema

-Frequency not reported: Decreased blood albumin, decreased blood potassium



-Uncommon (0.1% to 1%): Anxiety

-Rare (0.01% to 0.1%): Disorientation, euphoric mood

-Frequency not reported: Insomnia


Uncommon (0.1% to 1%): Cough, oropharyngeal pain, throat irritation

Frequency not reported: Dyspnea


-Common (1% to 10%): Hiccups

-Rare (0.01% to 0.1%): Postnasal drip, sneezing, oropharyngeal pain, cough, throat irritation

-Frequency not reported: Dyspnea, wheezing

Frequently asked questions


1. Product Information. Emend for Injection (fosaprepitant). Merck Sharp & Dohme LLC. 2022;SUPPL-21.

2. Product Information. Emend IV (fosaprepitant). Merck Sharp & Dohme (Australia) Pty Ltd. 2022.

3. Product Information. Ivemend (fosaprepitant). Merck Sharp & Dohme (UK) Ltd. 2022.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.