Ondansetron Nursing Considerations

Last updated on May 17th, 2022 at 09:00 am

Ondansetron Nursing Implications

Ondansetron Nursing Pharmacology

Ondansetron is a medication that is most commonly used to prevent nausea and vomiting, primarily caused by cancer treatments like chemotherapy and radiation therapy. It is also used to prevent nausea and vomiting in post-operative patients. 

Ondansetron is classified as a serotonin 5-HT3 receptor antagonist, it works by blocking serotonin, a natural substance in our body that induces vomiting.

5-HT3 receptors are found on the nerve terminals of the vagal nerve. Chemotherapy agents release serotonin that stimulates the vagal and the medullary vomiting center and also the 5-HT3 receptors that initiates vomiting reflexes resulting in nausea and vomiting

Indications for Ondansetron

Nausea and vomiting are two of the most common complaints seen in both emergency departments and primary care facilities.

Ondansetron is listed in the World Health Organization’s (WHO) list of essential medicines, which includes medications that they consider effective and safe to use that meet the immediate needs of a health system.

After years of its effectiveness, ondansetron’s popularity continues up to the present. In fact, in 2006, its brand name version was on the top list of highest-selling brand name medications in the United States.

Ondansetron is used to prevent nausea and vomiting associated with initial and repeated chemotherapy, radiation therapy (high dose cisplatin), and after surgery. It is considered a top choice treatment for chemotherapy and radiation-induced nausea and vomiting.

On the other hand, when it comes to motion sickness-related nausea and vomiting, it has minimal effect since it is mediated by other control centers.         

Side Effects of Ondansetron

Side effects in ondansetron happen in more than 10% of adults. Others experience only less common side effects. Tell your doctor if any of these symptoms are consistent and not relieved:

In some cases, side effects can be serious. the doctor must be notified  immediately or seek emergency medical treatment if any of these symptoms occur:

  • blurred vision or vision loss
  • rash
  • hives
  • itching
  • enlargement of the eyes, face, lips, tongue, throat, hands, feet, ankles, or lower legs
  • hoarseness
  • difficulty breathing or swallowing
  • chest pain
  • shortness of breath
  • dizziness, light-headedness, or fainting
  • fast, slow, or irregular heartbeat
  • agitation
  • hallucinations (seeing things or hearing voices that is not real)
  • fever
  • excessive sweating
  • confusion
  • nausea, vomiting, or diarrhea
  • loss of coordination
  • stiff or twitching muscles
  • seizures
  • coma (loss of consciousness)

It is highly advisable to call the doctor if any unusual problems happen while taking this medication.

Adverse Effects of Ondansetron

A temporary increase in liver function tests is shown in about 5% of people taking Ondansetron. Notify your doctor if you experience any serious side effects such as stomach pain,  muscle stiffness, changes in vision like blurring of vision, and temporary loss of vision.

Seek attention immediately if the patient experiences chest pain, irregularity in the heartbeat, extreme dizziness, and fainting. 

In some cases, an allergic reaction happens. This is an emergency that needs urgent medical attention, symptoms include rashes, itchiness, or swelling of the face or throat, severe dizziness, hypotension, and difficulty breathing.

In rare cases, taking Ondansetron may increase serotonin levels and may lead to a condition called serotonin syndrome or toxicity. This occurs most frequently among patients who are also taking serotonergic drugs such as SSRIs, SNRIs, MAOIs, fentanyl, lithium, tramadol, and methylene blue.

Consult the doctor if the patient develops symptoms like hallucinations, increased heart rate, muscle twitching, fever, severe dizziness, nausea and vomiting, agitation, and restlessness. Prolonged QT-interval and torsades de pointes are also reported. Other adverse effects may include:

  • headache
  • malaise/fatigue
  • constipation
  • hypoxia
  • drowsiness
  • diarrhea
  • dizziness
  • fever
  • gynecologic disorder
  • anxiety
  • urinary retention
  • pruritus
  • injection-site pain
  • paresthesia
  • cold sensation
  • elevated liver function test results

In particular, the following adverse effects should be noted when administering ondansetron:

  1. Cardiac: Arrhythmias (including ventricular and supraventricular tachycardia, premature ventricular contractions, and atrial fibrillation), bradycardia, electrocardiographic alterations (including second-degree heart block, QT/QTc interval prolongation, and ST-segment depression), palpitations, and syncope; rarely and predominantly with intravenous ondansetron, myocardial ischemia, transient ECG changes including QT/QTc interval prolongation have been reported
  2. Gastrointestinal: Nausea and vomiting
  3. Anaphylaxis
  4. ECG alterations: Arrhythmias; prolongation of PR, QRS, and QT intervals
  5. Hepatobiliary: Specific hepatic enzyme abnormalities, hepatic necrosis, and abnormal hepatic function
  6. General: Flushing, rare cases of hypersensitivity reactions, sometimes severe (eg, anaphylactic reactions, angioedema, bronchospasm, cardiopulmonary arrest, hypotension, laryngeal edema, laryngospasm, shock, shortness of breath, stridor)
  7. Local reactions: Pain, redness, and burning at the injection site
  8. Lower respiratory: Hiccups
  9. Neurological: Oculogyric crisis, appearing alone, as well as with other dystonic reactions; transient dizziness during or shortly after intravenous infusion
  10. Skin and subcutaneous tissue: Urticaria, Stevens-Johnson syndrome, and toxic epidermal necrolysis
  11. Eye Disorders: Transient blindness (predominantly during IV administration) reported to resolve within a few minutes up to 48 hr; transient blurred vision
  12. Musculoskeletal and connective tissue: Arthralgia

Drug Interactions with Ondansetron

Drug interactions identify which drug works in the body when combined, taken with certain other medications or foods, or when taken with particular medical conditions.

It may change the function of some medication or it may build risk for serious side effects. It is important to keep a list of all products the patient is using,  including prescribed and over-the-counter medicines, herbal products, vitamins, and supplements.

Do not take or discontinue or change the dosage of your medicine without the doctor’s advice. Inform the doctor about all the medicine the patient is using before starting ondansetron. The following drugs may cause interaction with ondansetron and should be prescribed with serious caution:

  • Morphine-containing medications, particularly apomorphine
  • Macrolide antibiotics

Nursing Considerations for Ondansetron

Medications to decrease nausea and vomiting are on the top list of frequently given drugs in the hospital and even at home.

However, managing it requires assessment skills and ample information on the pharmacologic actions and considerations needed to monitor to ensure the safety and effectiveness of the medication.

  1. Observe for the improvements within the gastrointestinal symptoms to take down if the drug therapy is working well with the patients. Symptoms to monitor include reduced incidents of nausea and vomiting and Improved appetite.
  2. Check for the patient’s motor function. Report to the doctor if any extrapyramidal reactions occur, common symptoms include:

  • tardive dyskinesia (uncontrollable movement of the face and its parts, extremities. Uncontrolled chewing, and movements of the tongue.)
  • Pseudoparkinsonism – these are symptoms that occur as a reaction to medication that imitates the symptoms of Parkinson’s disease. Symptoms of Parkinson’s disease are tremor, shuffling gait, rigidity, pill-rolling motion, loss of balance, difficulty swallowing, masklike face.
  • Akathisia or restlessness

3. Monitor for dizziness and drowsiness, for it may affect gait, balance, and movements. Report any balance problems and limits in function to the doctor. Inform the patient and relatives to watch, keep an eye on falls and trauma.

4.  Advised the patient to report if there are recurring and severe side effects they experience with the medication. These include prolonged headaches, weakness, tiredness, abdominal pain, diarrhea, constipation, and dry mouth.

5. For chemotherapy patients, give Ondansetron at least 30 minutes before the treatment.

6. In the case of radiation therapy, give Ondansetron 1 to 2 hours before the therapy. 

7. Check the status of fluid and electrolytes levels. In cases of diarrhea, which is one of the adverse effects of this drug, severe fluid and electrolytes loss may happen. Thus, dehydration and electrolyte imbalance might happen.

8. Assess the cardiovascular status, most especially among patients with a history of coronary artery disease. Few cases of increased heart rate and chest pain are reported.

9. For intravenous administration, give ondansetron slowly for at least 2 to 5 minutes. This is to avoid changes in heart rhythm such as fatal QT prolongation and ventricular tachycardia. When given to chemotherapy-induced nausea and vomiting, administer through IV infusion with diluted injection. For after-surgery nausea and vomiting, administer undiluted IV injection.  

10. For patients taking oral Ondansetron, remove the tablet from the blister Only before taking it, do not remove it from the blister ahead of time. Also, do not push the tablet through the foil. Open the blister pack with dry hands and place the tablet on the top of the tongue and allow it to dissolve completely, this drug is intended to dissolve on top of the tongue. Do not chew or swallow.

11. Monitor for any symptoms of QT-interval prolongation and torsades de pointes. Seek medical care immediately if any of these symptoms occur: Faintness, lightheadedness, arrhythmia, shortness of breath, and dizziness. Therefore, avoid giving ondansetron in patients with congenital prolonged QT-interval syndrome. Ask the patient if they have a family history of irregular heartbeat, heart failure, electrolyte imbalances, or liver disease.       

12. Monitor patient’s ECG. This is to check if there are abnormalities with the electrolytes. Congestive heart failure or abnormally, slow heartbeat to those with known QT-interval. 

13. Check for hypersensitivity with ondansetron or any included ingredients.

14. Do not give ondansetron to stimulate gastric muscle contractions. Also, do not use it as a replacement for nasogastric suction.

15. Provide caution when giving to patients with severe hepatic function problems, preferably at a reduced dosage.

16. Take ondansetron exactly as prescribed by the physician. For any questions or clarifications, consult the physician. 

17. Advised the patient to keep this medication in the container it came in, properly closed, and keep out of reach of children. Store the tablet away from direct light, excess heat, and moisture. Keep it at room temperature or can be placed in a refrigerator.

18. In case of overdose, call the poison hotline if there’s available or bring it to the nearest hospital. Symptoms of overdose are:

  • Sudden Loss of vision
  • Dizziness
  • Lightheadedness
  • Fainting
  • Constipation
  • Arrhythmia

19. Advice the patient to inform the doctor about other prescribed drugs they are taking. It also includes vitamins, supplements, herbal medicine, and other health-related products. Take caution if they are taking any of the following: certain medications for seizures, medications for irregular heart beat; medications for mental illness; medications to treat migraines, monoamine oxidase, selective serotonin reuptake inhibitors (SSRIs). Your doctor may need to change the doses of your medications or monitor you more carefully for side effects. Many other medications may also interact with ondansetron, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.

20. If the patient is pregnant or planning to become pregnant, tell the doctor first before taking ondansetron.

21. In case the patient missed a dose, take it as soon as they remember. But if it is almost time for the next dose, skip the missed dose and continue with the regular dosing schedule. Do not take a double dose.

22. Patients with phenylketonuria should be cautious in taking ondansetron. The tablet formulation can contain phenylalanine.

23. Because of potential dose-dependent QT-interval prolongation, aside from ECG monitoring, magnesium levels are also advised to be monitored, especially in susceptible populations. These include the elderly and patients with electrolyte abnormalities such as hypokalemia, hypomagnesemia, heart failure, bradyarrhythmias, or patients on other medications that may prolong the QTc interval.

24. Another reported case in patients treated with ondansetron is Myocardial ischemia. In a few cases during intravenous administration, the symptoms occur right after administration but are resolved with immediate treatment. It shows that the most common underlying cause is Coronary artery spasm. Assess and monitor the patients for signs or symptoms of myocardial ischemia after taking oral ondansetron.

25. Taking ondansetron will make you feel dizzy or drowsy. If that happens, do not drive, do not use machines or anything that needs alertness. Also, avoid alcoholic beverages. To reduce dizziness and lightheadedness, advise the patient to get up slowly when rising from a lying or sitting position.

26. Inform the physician if the patient has an irregular heartbeat, an existing medical diagnosis like liver disease, gastrointestinal problem, recent surgeries.

27. It is still unknown if the drug passes through breast milk. If the patient is breastfeeding, talk to the physician the soonest time possible.

28. Though ondansetron is effective in preventing nausea and vomiting in chemotherapy, radiation therapy, and post-surgery procedures, it is not recommended to give ondansetron as prophylaxis especially if there’s only a small chance that nausea or vomiting will occur.

29. For patients taking ondansetron liquid solution, use the correct measuring cup to get an accurate dosage of the medication.

30. For patients younger than 4 years of age, sufficient and appropriate studies have not yet been performed on the relationship between age and the effect of ondansetron in younger children.

Ondansetron Nursing Diagnoses

  • Disturbed Sensory Perception related to the side effect of Ondansetron
  • Constipation related to the side effect of Ondansetron
  • Pain (Headache) related to the side effect of Ondansetron
  • Risk for Bleeding  related to adverse effect of Ondansetron
  • Risk for Anaphylactic Reaction related to drug allergy to Ondansetron
  • Risk for Electrolyte Imbalance (Hypokalemia/ Hypomagnesemia) secondary to adverse reaction of Ondansetron

Ondansetron Nursing Assessment

Ondansetron Nursing InterventionsRationale
Assess the patient for signs and symptoms of nausea and vomiting, especially if they are on chemotherapeutic agents.To confirm the indication for administering ondansetron.
Assess if the patient takes apomorphine. Check the patient’s medical and family history for:
– Liver disease
– Long QT syndrome
– Hypokalemia
– Hypomagnesemia
– Congestive heart failure
– Bradycardia
– Gastrointestinal blockage
Ondansetron is generally contraindicated in patients taking apomorphine. Ondanstetron should be used with extreme caution in patients with hypokalemia and hypomagnesemia because one of the adverse effects of this drug is to lower the serum potassium and magnesium level. Patients with C.difficile infection, seizures, clotting disorders, or chronic kidney disease may receive Ondansetron with caution.
Check the patient’s age and allergy status.Ondansetron is not recommended for pediatric patients under 4 years old. Previous allergic reactions to ondansetron may render the patient unable to take them. Alternatives to Ondansetron should therefore be considered in case of allergy.
Assess if the patient is pregnant.Ondansetron can be prescribed to a pregnant woman  as this drug is under pregnancy category B which means it does not impose known harm to humans. However, ondansetron is not advisable for pregnant patients during the first trimester as research shows that there is a small risk to develop cleft lip or palate of the fetus.
Perform a focused neurological assessment of the patient.Ondansetron may cause adverse CNS effects.  
Assess the patient’s veins in preparation for administering IV ondansetron. Check if the patient is able to swallow oral ondansetron as prescribed.To ensure that there is a good venous access before IV ondansetron is given. Oral ondansetron can be given if the patient does not have any swallowing problems.
Collect blood for a liver function check.Ondansetron may cause adverse effects on the kidneys if not dosed properly.

Ondansetron Nursing Planning and Intervention

Ondansetron Nursing InterventionsRationale
Administer IV ondansetron via a peripheral or central venous line.To ensure optimal absorption and therapeutic action by ondansetron, as well as reduce possible side effects.
Monitor the venous access after administration. Ask the patient to report any pain or discomfort during and after administration of the drug.To check for any infiltration or phlebitis around the IV site.  
Educate the patient about the action, indication, common side effects, and adverse reactions to note when taking ondansetron.To inform the patient on the important information regarding ondansetron.
Perform an hourly visit/ intentional rounding when the patient is on ondansetron. Assist the patient with activities of daily living as required.Ondansetron may cause dizziness and drowsiness. The patient may require assistance with ADLs and must be checked at least every hour.
Inform the patient that ondansetron may cause headache, drowsiness, or constipation and any of these should be reported to any healthcare professional once noticed.To inform the patient of the possible side effects of ondansetron on the body, and to be able to deal with the symptom as soon as the patient reports it.

Ondansetron Nursing Evaluation

Ondansetron Nursing InterventionsRationale
Ask the patient to repeat the information about Ondansetron.To evaluate the effectiveness of health teaching on ondansetron.
Check for any signs of allergic reaction to ondansetron, such as shortness of breath, skin rash, or swelling.To ensure the patient’s safety after the initial dose of ondansetron and to be able to reverse anaphylaxis quickly.
Monitor the patient’s full blood count and liver function.To ensure that ondansetron did not cause any damage to the patient’s liver function.  
Monitor the patient for any signs of erratic heartbeats or bradycardia.To check for any adverse cardiac effect of ondansetron which is long QT syndrome.

Nursing References

Ackley, B. J., Ladwig, G. B., Makic, M. B., Martinez-Kratz, M. R., & Zanotti, M. (2020). Nursing diagnoses handbook: An evidence-based guide to planning care. St. Louis, MO: Elsevier.  Buy on Amazon

Gulanick, M., & Myers, J. L. (2022). Nursing care plans: Diagnoses, interventions, & outcomes. St. Louis, MO: Elsevier. Buy on Amazon

Ignatavicius, D. D., Workman, M. L., Rebar, C. R., & Heimgartner, N. M. (2018). Medical-surgical nursing: Concepts for interprofessional collaborative care. St. Louis, MO: Elsevier.  Buy on Amazon

Silvestri, L. A. (2020). Saunders comprehensive review for the NCLEX-RN examination. St. Louis, MO: Elsevier.  Buy on Amazon


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The medical information on this site is provided as an information resource only and is not to be used or relied on for any diagnostic or treatment purposes.

This information is intended to be nursing education and should not be used as a substitute for professional diagnosis and treatment.

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Anna Curran. RN, BSN, PHN

Anna Curran. RN-BC, BSN, PHN, CMSRN I am a Critical Care ER nurse. I have been in this field for over 30 years. I also began teaching BSN and LVN students and found that by writing additional study guides helped their knowledge base, especially when it was time to take the NCLEX examinations.

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