Serotonin antagonists (5-HT3 receptor antagonists)

Search Knowledgebase

Topic Contents

Serotonin antagonists (5-HT3 receptor antagonists)


Generic NameBrand Name

Serotonin antagonists may be given as a pill, as a patch, or as a shot.

How It Works

Serotonin antagonists work by blocking the effects of a chemical called serotonin, which is produced in the brain and the stomach.

Why It Is Used

Serotonin antagonists prevent and relieve nausea and vomiting caused by chemotherapy. They also are used before surgery to prevent nausea and vomiting caused by anesthesia. Serotonin antagonists also decrease episodes of bulimia in people with bulimia nervosa.

How Well It Works

Serotonin antagonists prevent and relieve nausea and vomiting caused by chemotherapy and anesthesia. They are more effective when they are given with other medicines, such as dexamethasone and aprepitant (Emend), if used for nausea or vomiting caused by chemotherapy.1

Side Effects

Although serotonin antagonists cause fewer side effects than other antinausea medicines (antiemetics), side effects can include:

  • Diarrhea or constipation.
  • Dizziness and headache.
  • Fatigue and sleepiness.
  • Muscle cramps.
  • Nervousness.

Side effects from serotonin antagonist patches may also include reactions on the skin, such as redness, rash, or blisters, where the patch is placed.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Serotonin antagonists are often used with other medicines, such as dexamethasone and aprepitant (Emend), to prevent and control nausea and vomiting caused by chemotherapy.

These medicines should not be used by children who weigh less than 9 kg (20 lb) or are younger than age 3.

It is not known whether serotonin antagonists pass into breast milk. If you are breast-feeding, do not take these medicines without first talking to your doctor.

Although serotonin antagonists may be safe for use during pregnancy, do not take these medicines until you have discussed your pregnancy with your doctor.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. Berger AM, Clark-Snow RA (2005). Adverse effects of treatment. In VT DeVita Jr et al., eds., Cancer: Principles and Practice of Oncology, 7th ed., pp. 2515–2523. Philadelphia: Lippincott Williams and Wilkins.


By Healthwise Staff
Primary Medical Reviewer Joy Melnikow, MD, MPH - Family Medicine
Specialist Medical Reviewer Douglas A. Stewart, MD - Medical Oncology
Specialist Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Last Revised October 20, 2009

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.