5HT3 Antagonists

Other names: Palonosetron (Aloxi®), Ondansetron (Zofran®), Dolasetron (Anzemet®), Granisetron (Kytril®)

About This Drug

5-HT3 Receptor Antagonists are medications that are used before and after chemotherapy to prevent or treat nausea or vomiting. These medications can be given in an intravenous (IV) infusion, as an oral tablet by mouth, as an orally disintegrating tablet, or as a patch.

Possible Side Effects (More Common)

  • Constipation (not being able to move bowels)
  • Loose bowel movements (diarrhea) that may last for a few days
  • Headache
  • Generalized weakness and discomfort (aches or pains)

Possible Side Effects (Less Common)

  • Your heart tissue can be harmed. This may cause your heart to beat in a way that is not normal. Your doctor may order an EKG to check this.

Allergic Reactions

Allergic reactions, including anaphylaxis are rare but may happen in some patients. Signs of allergic reaction to this drug may be swelling of the face, feeling like your tongue or throat are swelling, trouble breathing, rash, itching, fever, chills, feeling dizzy, and/or feeling that your heart is beating in a fast or not normal way. If this happens, do not take another dose of this drug. You should get urgent medical treatment.

Treating Side Effects

  • Ask your doctor or nurse about medicines that are available to help stop or lessen constipation.
  • If you are not able to move your bowels, check with your doctor or nurse before you use enemas, laxatives, or suppositories
  • Drink 6-8 cups of fluids each day unless your doctor has told you to limit your fluid intake due to some other health problem. A cup is 8 ounces of fluid. If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack water in the body from losing too much fluid).

Food and Drug Interactions

There are no known interactions of 5-HT3 Antagonists with food. These drugs interact with tobacco, so tell your doctor if you smoke or use tobacco. These drugs may interact with other medications. Tell your doctor and pharmacist about all the medication and dietary supplements (vitamins, minerals, herbs, and others) that you are currently taking. The safety and effectiveness of dietary supplements and alternative diets are often unknown. Using these might unexpectedly affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.

When to Call the Doctor

Call your doctor or nurse immediately if you have any of the following symptoms:

  • Feeling that your heart is beating in a fast or not normal way (palpitations)
  • Loose bowel movements (diarrhea) more than 4 times a day or diarrhea with weakness or lightheadedness
  • Wheezing or trouble breathing
  • Rash or itching
  • Feeling dizzy or lightheaded

Call your doctor or nurse as soon as possible if any of the following symptoms occur:

  • No bowel movement in 3 days or when you feel uncomfortable.
  • Loose bowel movements (diarrhea) 4 times or loose bowel movements with lack of strength or a feeling of being dizzy
  • Fatigue that interferes with your daily activities

Reproduction Concerns

  • Pregnancy warning: This drug is not expected to harm an unborn child. Talk to your doctor about the use of this drug if you are pregnant or plan to become pregnant.
  • Breast feeding warning: It is not known if this drug passes into breast milk. For this reason, women should talk to their doctor about the risks and benefits of breast feeding during treatment with this drug because this drug may enter the breast milk and badly harm a breast feeding baby.

Last updated March 2016