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Ondansetron Patient Tips

Medically reviewed on Sep 14, 2017 by C. Fookes, BPharm.

How it works

  • Ondansetron treats and prevents nausea and vomiting by an unknown mechanism, possibly by a direct effect on the CTZ (the area of the brain associated with vomiting), the vagus nerve or both. The neurotransmitter, serotonin, appears to play a role in ondansetron's effect.
  • Ondansetron belongs to the class of medicines known as 5-HT3 receptor antagonists.

Upsides

  • Effective for the prevention of nausea and vomiting associated with cancer chemotherapy, including highly emetogenic (a high probability of causing vomiting) chemotherapy.
  • May also be used to prevent nausea and vomiting associated with radiotherapy - this includes total body irradiation or single or multiple high-dose or daily fractions to the abdomen.
  • Effective at preventing postoperative nausea and vomiting.
  • Generic ondansetron is available.

Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Tiredness, a headache, drowsiness, dizziness, constipation, flushing, itching, slowed heart rate, raised body temperature, and diarrhea.
  • Rarely may cause hiccups, blurred vision or vision loss, a rash or liver disturbances.
  • Interaction or overdosage may cause serotonin syndrome (symptoms include agitation, hallucinations, fast heart rate, dizziness, muscle tremor, nausea, vomiting, diarrhea).
  • May interact with some medications including apomorphine (may cause a profound drop in blood pressure and loss of consciousness), and drugs metabolized by CYP3A4 (although few clinically significant interactions have been reported).
  • May not be suitable for some people including those with liver disease or a personal or family history of long QT syndrome.
  • Orally disintegrating ondansetron tablets may contain phenylalanine. Tell your doctor if you have phenylketonuria (PKU).

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

Bottom Line

Ondansetron may be used for the prevention or treatment of nausea and vomiting but it may cause constipation or a headache.

Tips

  • May be taken with or without food. Take oral tablets with a big glass of water.
  • Consider laxatives to relieve constipation.
  • When taking the orally disintegrating tablets, peel back the foil (do not attempt to push the tablet through the foil). Allow the tablet to dissolve in your mouth without chewing.
  • When taking the oral soluble strip film, use dry hands to remove the strip and place on your tongue. Leave to dissolve without chewing. Swallow several times after the strip dissolves. A glass of water may help with dissolution.
  • When taking ondansetron oral solution, measure the correct dosage with the dosing syringe provided.
  • Monitor for serotonin syndrome (symptoms include mental status changes [such as agitation, hallucinations, coma, delirium]), fast heart rate, dizziness, flushing, muscle tremor or rigidity and stomach symptoms [including nausea, vomiting, diarrhea]).
  • Report to your doctor any other unusual side effects.
  • If ondansetron makes you dizzy or drowsy, do not drive or operate machinery while affected and avoid alcohol.

Response and Effectiveness

The peak effect of ondansetron is seen within 1.5-2 hours. The onset of the effect is faster with the wafer form of ondansetron.

References

Ondansetron [Package Insert] Revised 05/2017. Aidarex Pharmaceuticals LLC. https://www.drugs.com/pro/ondansetron.html

  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use ondansetron only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that this information is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This drug information does not endorse drugs, diagnose patients or recommend therapy. It is an informational resource designed as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of this information. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2017 Drugs.com. Revision Date: 2017-09-14 01:45:31

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