How does Zofran work to prevent nausea and vomiting. What is the recommended dosage for adults and children. Can Zofran be taken more frequently than every 8 hours. What are the potential side effects and precautions when using Zofran.

Understanding Zofran: A Powerful Antiemetic Medication

Zofran, also known by its generic name ondansetron, is a prescription medication primarily used to prevent nausea and vomiting. It belongs to a class of drugs called 5-HT3 receptor antagonists, which work by blocking the action of serotonin, a natural substance in the body that can trigger nausea and initiate the vomiting reflex.

This medication is particularly effective for patients undergoing cancer treatments such as chemotherapy and radiation therapy, as well as for those experiencing post-operative nausea and vomiting. Zofran is available in various forms, including oral tablets, orally disintegrating tablets, oral films, oral solution, and injection vials, providing flexibility in administration based on patient needs and preferences.

Key Points About Zofran

• Generic name: Ondansetron
• Drug class: 5-HT3 receptor antagonist
• Primary use: Prevention of nausea and vomiting
• Available forms: Oral tablets, orally disintegrating tablets, oral films, oral solution, and injection vials

Zofran Dosage Guidelines: Tailoring Treatment to Patient Needs

The dosage of Zofran varies depending on the patient’s age, the severity of nausea and vomiting, and the specific medical condition being treated. It’s crucial to follow the prescribed dosage and frequency as determined by a healthcare provider.

Adult Dosage for Chemotherapy-Induced Nausea and Vomiting

• Severe cases: 24 mg single dose, taken 30 minutes before highly emetogenic chemotherapy
• Moderate cases: 8 mg taken 30 minutes before chemotherapy, followed by another 8 mg dose 8 hours later

Adult Dosage for Radiation Therapy-Induced Nausea and Vomiting

8 mg taken 1-2 hours before radiation therapy, followed by 8 mg every 8 hours as needed, depending on the type and location of radiation.

Adult Dosage for Post-Operative Nausea and Vomiting

16 mg administered 1 hour before anesthesia.

Pediatric Dosage for Chemotherapy-Induced Nausea and Vomiting

• Ages 4-11: 4 mg taken 30 minutes before chemotherapy, followed by 4 mg doses at 4 and 8 hours after the first dose
• Ages 12-17: 8 mg taken 30 minutes before chemotherapy, followed by another 8 mg dose 8 hours later

Is the dosage of Zofran the same for all patients. No, the dosage varies based on factors such as age, severity of symptoms, and the specific condition being treated. Always consult with a healthcare provider for personalized dosing instructions.

Frequency of Zofran Administration: Finding the Right Balance

The frequency of Zofran administration is carefully determined to maintain effective control of nausea and vomiting while minimizing the risk of side effects. In most cases, Zofran is taken every 8 to 12 hours, or 2-3 times a day.

Can Zofran be taken more frequently than every 8 hours. While in some specific cases, such as in children undergoing chemotherapy, doses may be given as close as 4 hours apart, it’s generally not recommended to take Zofran more frequently than prescribed. The total daily dose should not exceed the maximum recommended amount, which is typically 24 mg for adults.

Factors Influencing Zofran Frequency

• Severity of nausea and vomiting
• Patient’s age and weight
• Liver function
• Concurrent medications
• Type of treatment (e.g., chemotherapy, radiation, surgery)

Why is Zofran typically administered every 8 hours. This dosing schedule is based on the drug’s pharmacokinetics and has been shown in clinical trials to provide optimal control of nausea and vomiting while maintaining a favorable safety profile.

Potential Side Effects and Precautions When Using Zofran

While Zofran is generally well-tolerated, like all medications, it can cause side effects in some patients. It’s important to be aware of these potential side effects and to report any concerning symptoms to a healthcare provider.

Common Side Effects of Zofran

• Headache
• Constipation
• Fatigue
• Dizziness
• Drowsiness

Serious Side Effects Requiring Immediate Medical Attention

• Irregular heartbeat
• Chest pain
• Shortness of breath
• Severe dizziness or fainting
• Signs of an allergic reaction (rash, itching, swelling, severe dizziness, difficulty breathing)

What precautions should be taken when using Zofran. Patients with severe liver disease should not take more than 8 mg of Zofran per day. The medication is not FDA-approved for use during pregnancy, although some studies have shown its safety in treating morning sickness during the first trimester. Always consult with a healthcare provider before using Zofran if pregnant or breastfeeding.

Drug Interactions: Ensuring Safe Use of Zofran

Zofran can interact with various medications, potentially altering its effectiveness or increasing the risk of side effects. It’s crucial to inform healthcare providers about all medications, supplements, and herbal products being used before starting Zofran treatment.

Medications That May Interact with Zofran

• Apomorphine
• Tramadol
• Selective serotonin reuptake inhibitors (SSRIs)
• Serotonin-norepinephrine reuptake inhibitors (SNRIs)
• Certain heart medications (e.g., amiodarone, sotalol)
• Medications that affect liver enzymes (e.g., carbamazepine, phenytoin)

How can patients minimize the risk of drug interactions with Zofran. Always provide a complete list of all medications, including over-the-counter drugs and supplements, to healthcare providers. Follow dosing instructions carefully and avoid making changes to medication regimens without consulting a healthcare professional.

Special Considerations for Zofran Use in Specific Populations

Certain populations may require special considerations when using Zofran. These include children, elderly patients, pregnant women, and individuals with liver or kidney problems.

Zofran Use in Children

Zofran is approved for use in children aged 4 years and older for chemotherapy-induced nausea and vomiting. The dosage is typically lower than that for adults and is based on the child’s weight.

Zofran Use in Elderly Patients

Elderly patients may be more sensitive to the effects of Zofran and may require dose adjustments. Close monitoring for side effects is important in this population.

Zofran Use During Pregnancy and Breastfeeding

While not FDA-approved for use during pregnancy, some studies have shown Zofran’s safety in treating morning sickness during the first trimester. However, the decision to use Zofran during pregnancy or while breastfeeding should be made in consultation with a healthcare provider, weighing the potential benefits against the risks.

Zofran Use in Patients with Liver or Kidney Problems

Patients with severe liver disease should not exceed 8 mg of Zofran per day. Those with kidney problems may also require dose adjustments. Regular monitoring of liver and kidney function may be necessary for these patients.

Are there any alternatives to Zofran for patients who cannot take it. Yes, there are several alternative antiemetic medications available, including other 5-HT3 receptor antagonists, dopamine antagonists, and NK1 receptor antagonists. The choice of alternative medication depends on the specific cause of nausea and vomiting, as well as individual patient factors.

Maximizing the Effectiveness of Zofran Treatment

To get the most benefit from Zofran treatment, patients should follow certain guidelines and best practices. These can help ensure optimal control of nausea and vomiting while minimizing the risk of side effects.

Tips for Effective Zofran Use

• Take Zofran exactly as prescribed by your healthcare provider
• For prevention of chemotherapy-induced nausea, take the first dose 30 minutes before treatment begins
• If using the orally disintegrating tablet, allow it to dissolve on the tongue; do not chew or swallow it whole
• Stay well-hydrated, especially if experiencing vomiting
• Keep track of doses taken and any side effects experienced
• Do not stop taking Zofran abruptly without consulting your healthcare provider

How can patients complement Zofran treatment with non-pharmacological methods. In addition to taking Zofran, patients can try various non-drug approaches to manage nausea and vomiting, such as eating small, frequent meals, avoiding strong odors, practicing relaxation techniques, and using acupressure bands. These methods can work synergistically with Zofran to provide comprehensive symptom relief.

Long-Term Use of Zofran: Benefits and Considerations

While Zofran is often used for short-term management of acute nausea and vomiting, some patients may require long-term treatment, particularly those undergoing extended courses of chemotherapy or radiation therapy.

Potential Benefits of Long-Term Zofran Use

• Improved quality of life for cancer patients undergoing prolonged treatment
• Better adherence to chemotherapy and radiation therapy regimens
• Reduced risk of complications related to severe nausea and vomiting

Considerations for Long-Term Zofran Use

• Regular monitoring for potential side effects
• Periodic evaluation of continued need for treatment
• Possible dose adjustments based on response and tolerability
• Awareness of potential drug interactions with long-term medications

Is it safe to use Zofran long-term. While Zofran is generally well-tolerated, long-term use should be closely monitored by a healthcare provider. Regular check-ups and possibly periodic blood tests may be necessary to ensure continued safety and effectiveness of the treatment.

In conclusion, Zofran (ondansetron) is a valuable medication for managing nausea and vomiting associated with various medical conditions and treatments. By understanding its proper use, dosage guidelines, potential side effects, and special considerations, patients can maximize the benefits of this medication while minimizing risks. Always consult with a healthcare provider for personalized advice on using Zofran effectively and safely.

How Often Can I Take Zofran (Ondansetron) When Nauseous?

Written by
Juhi Modi

Medically reviewed by
HaVy Ngo-Hamilton, Pharm.D.
| Updated Jun 13, 2023

If you are experiencing nausea and vomiting after surgery or cancer treatment, such as chemotherapy and radiation, your doctor may prescribe a medication called ondansetron (brand name: Zofran). Please continue reading to learn more about this medicine, including its uses, dosage, frequency of use, drug interactions, and tips on safe use. 

What is ondansetron (Zofran)?

Ondansetron (Zofran, Zofran ODT) is a prescription medication used to prevent nausea and vomiting for cancer patients after chemotherapy and radiation treatment. This medication is also used to treat nausea after surgery. It is available in various dosage forms, including oral tablets (4 mg, 8 mg, and 24 mg), orally disintegrating tablets and oral films (4 mg and 8 mg), oral solution (4 mg/5 mL), and injection vials (2 mg/mL).

These different dosage forms, such as the orally disintegrating tablets, the oral liquid, and the oral film, help lessen the nauseating feeling that may be caused by swallowing a tablet. Some of the uses of ondansetron (Zofran) may not be listed in this article.

How does Zofran work?

Zofran is an antiemetic that belongs to a group of drugs called 5-HT3 receptor antagonists. It works by blocking the action of serotonin, a natural substance in the body that can trigger nausea and initiate a vomiting reflex.

What is the usual dose of Zofran?

The usual dose of ondansetron (Zofran) in adults and children is as follows: 

Adults

• Severe nausea and vomiting due to chemotherapy: a single 24-mg dose to be taken 30 minutes before the start of a single day of highly emetogenic (vomiting-inducing) chemotherapy.  
• Moderate nausea and vomiting due to chemotherapy: An 8-mg dose is administered 30 minutes before the start of chemotherapy, followed by another 8-mg dose 8 hours later. After the completion of chemotherapy, 8 mg of Zofran should be taken every 12 hours for 1 to 2 days.
• Radiation therapy: An 8-mg ondansetron is taken 1-2 hours before radiation therapy. After the first dose, the regimen of 8 mg every 8 hours is recommended depending on the type and the location of radiation.
• Post-operative (after-surgery) nausea and vomiting: 16 mg of ondansetron is to be administered 1 hour before anesthesia.

  Children:

• Age 4 to 11: For moderate nausea and vomiting due to chemotherapy, take 4 mg of ondansetron (Zofran) 30 minutes before the start of chemotherapy, followed by another 4 mg dose given at 4 and 8 hours after the first dose. After the completion of chemotherapy, take 4 mg of ondansetron (Zofran) every 8 hours for 1 to 2 days.
   
• Age 12 to 17: For moderate nausea and vomiting due to chemotherapy, take 8 mg of ondansetron (Zofran) 30 minutes before the start of chemotherapy, followed by another 8 mg dose given 8 hours after the first dose. After the completion of chemotherapy, take 8 mg of ondansetron (Zofran) every 12 hours for 1 to 2 days.

Precautions:

• People with severe liver disease should not take more than 8 mg of ondansetron in a day.
• Zofran is not approved by the FDA to be used during pregnancy. However, there are studies that show Zofran’s safety in treating morning sickness during the first trimester. You should discuss with your doctor if you are pregnant or breastfeeding. 
• Do not give Zofran to children younger than 4 years old. 

Can I take Zofran again after 4 hours?

In some cases, you may take Zofran again after 4 hours. For example, in children, 4 mg or 8 mg of Zofran is given 30 minutes before the start of chemotherapy. (The dose is 4 mg in children between 4 and 11 years of age and 8 mg in children between 12 and 17 years of age.) This is followed by another dose 4 hours later and then one more dose 8 hours after the first dose. The child is then given one dose every 8 hours for 1-2 days after completion of chemotherapy.

Can you take Zofran every 6 hours?

The usual frequency of Zofran dosing in adults is an 8 mg tablet every 8-12 hours or 2-3 times a day. A scenario where you could take it more frequently would be if the dose taken was less than 8mg. Nevertheless, the sum of the doses taken cannot exceed 8 mg within that time frame. You should not take this medicine more often than prescribed, so leave it to your provider to determine your dose frequency. Talk to your doctor or pharmacist if your nausea and vomiting are not controlled with the prescribed dose and frequency of Zofran. 

Why can you only take Zofran every 8 hours? 

You can only take Zofran every 8 hours because clinical trials have shown that ondansetron (Zofran) increases the risk of QT prolongation. This is an abnormality in the heart’s electrical system. The risk of QT prolongation appears to be dose related. For this reason, doctors do not give intravenous (IV) doses of more than 16 mg or advise taking Zofran more often than every 8 hours when at home and without proper monitoring of a patient’s vitals.

What are the risks associated with Zofran use?

Severe allergic reactions

In a small number of people, Zofran can cause severe allergic reactions with signs and symptoms such as difficulty breathing, swelling of the throat, skin rash, and other effects. Stop taking ondansetron (Zofran) and seek immediate medical attention if you experience symptoms while on this medication to control nausea and vomiting after cancer treatment or surgery.

Serotonin syndrome

Patients taking too much ondansetron (Zofran) can develop a serious and potentially life-threatening condition called serotonin syndrome. This occurs due to high serotonin levels in the body. The risk is higher in people taking other drugs that affect serotonin levels, such as lithium, antidepressants, and migraine medications. Symptoms of serotonin syndrome may include sweating, fast heartbeat, nausea and vomiting, muscle spasms, muscle stiffness, blurred vision, confusion, and fever. Seek emergency medical attention immediately if you develop any of these symptoms while on Zofran.

Heart rhythm problems

High doses of ondansetron (Zofran) can increase the risk of heart rhythm problems, also known as arrhythmias. The risk is higher in people with congenital long QT syndrome or a history of QT prolongation. Taking other medications that cause heart rhythm problems, congestive heart failure, and low potassium or magnesium can also lead to an increased risk. Tell your healthcare provider if you have any heart rhythm abnormalities before starting ondansetron. Contact your doctor if you notice signs and symptoms such as chest pain, palpitations, slow heartbeat, or irregular heartbeat.

Masking of intestinal blockage symptoms

When you take ondansetron to treat nausea and vomiting after abdominal surgery or chemotherapy, the medicine can mask some of the symptoms of intestinal blockage and abdominal bloating, which happen to be nausea and vomiting. Tell your healthcare provider if you are not passing gas or stools. 

Risk to people with phenylketonuria

People with a rare disorder called phenylketonuria cannot break down an amino acid called phenylalanine. High levels of phenylalanine in the body can cause serious health problems. The orally disintegrating tablet of ondansetron (Zofran ODT) contains phenylalanine. Needless to say, consult your doctor before starting Zofran ODT if you have phenylketonuria.

Tips on the safe use of ondansetron (Zofran)

• Give your doctor or pharmacist a complete list of your medications, including prescription drugs, over-the-counter medicines, dietary supplements, and herbal remedies. This can help avoid dangerous drug interactions between ondansetron and another OTC product or prescription medication.
• You can take ondansetron with or without food.
• If you are taking the disintegrating tablet of Zofran, remove the foil backing with dry hands and immediately place the tablet under your tongue.
• Besides common side effects of ondansetron, like headache, tiredness, diarrhea, and constipation, this medicine can also cause dizziness. Do not drive or operate machinery until you know how ondansetron affects you. Drinking alcohol can make these side effects worse.
• In case of a missed dose, take your Zofran dose as soon as you remember. If it is time for the next dose, however, skip the missed dose and take the next dose according to the prescribed schedule. Do not take two doses to make up for a missed dose.

References:

1. https://medlineplus.gov/druginfo/meds/a601209.html
2. https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/020103s035_020605s019_020781s019lbl.pdf
3. https://journals.lww.com/ajnonline/Abstract/2012/10000/The_FDA_Limits_Maximum_IV_Dose_of_Ondansetron. 27.aspx

Ondansetron (Zofran)

How does this medicine work?

Ondansetron (on-dan-se-tron) is a medicine used to treat and prevent nausea and vomiting.

How should I give it?

Ondansetron may be given by mouth as a liquid, pill, or tablet; or in a vein (IV). It may be given in one of these ways:

• as needed
• at regular times
• continuously through an IV

Your child should be awake and alert when taking any medicine by mouth. Follow the checked instructions below:

___ If using the liquid form, draw up the correct amount in the medicine dropper or oral syringe. Give a small squirt of the medicine inside the cheek. To avoid choking, let your child swallow each squirt before giving more.

___ For babies, you may want to mix the medicine with a small amount of formula or breast milk and give it with a bottle nipple before feeding. Do not add the medicine to a whole bottle because if your baby does not finish it, you will not know how much of the medicine was taken.

___ For older children who cannot swallow pills, a special tablet called Zofran ODT (oral disintegrating tablet) is available. Place it under the tongue and it will dissolve.

Other instructions:

Are there any precautions about food or other medicines?

This medicine may be given with or without food.

Check with the doctor, nurse practitioner, or pharmacist before giving any other prescription or non-prescription medicines, herbs, or vitamins.

What should I do if a dose is missed?

If a dose is missed, give it as soon as you remember. Never give a double dose.

If your child vomits a regular dose (not of the ODT type) within 30 minutes after receiving it, give it again. If your child vomits the second dose, do not repeat it again. If your child vomits an ODT dose, do not repeat it. Ondansetron ODT is absorbed into the body right away.

If your child misses or vomits two doses in a row, please call the clinic.

What are the side effects?

Common

• headache
• constipation

Occasional

• fatigue
• change in liver tests (with long-term use)
• diarrhea
• feeling dizzy

When should I call the clinic?

• continued vomiting after 2 doses
• signs of allergic reaction:
  • fever or chills
  • rash or hives
  • wheezing
  • trouble breathing – call 911

What else do I need to know?

You and your child should know the names and doses of all medicines he or she is taking. Share this information with anyone involved in your child’s care. Please remember to bring the medicine container when your child comes to the clinic or emergency department.

Always make sure you have enough medicine on hand. Each time you refill the prescription, check to see how many refills are left. If no refills are left, the pharmacy will need 2 or 3 days to contact the clinic to renew the prescription.

Check the label and the expiration date before giving each dose. Ask your pharmacist what to do with outdated or unused medications. Empty them into the trash if there is no “take-back” program.

Store all medicines in their original containers and away from direct sunlight or heat. Do not store in humid places such as the bathroom. Keep them out of children’s reach; lock up if possible.

If too much or the wrong kind of medicine is taken, call the Poison Control Center toll-free at 1-800-222-1222. If your child is unconscious or has a seizure, call 911.

Questions?

This sheet is not specific to your child but provides general information. If you have any questions, please call the clinic or pharmacy.

Children’s Hospitals and Clinics of Minnesota
Patient/Family Education
2525 Chicago Avenue South
Minneapolis, MN 55404
Last reviewed 8/2015 ©Copyright

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Use of ondansetron in the treatment of children with cancer

Supportive care

Trademarks:

Zofran®

Other names:

Ondansetron Hydrochloride

Often used for:

treatment of nausea and vomiting

Ondansetron is a drug that is used to prevent and treat nausea and vomiting during chemotherapy and radiation therapy, as well as in the postoperative period.

The rate of breakdown of ondansetron in the body may vary. This is determined by the activity of an enzyme called P450 2D6 (CYP2D6). Genetic analysis may be required to determine the quality of the enzymes in a particular patient. The drug may not be effective enough if the rate of breakdown of ondansetron in the patient’s body is higher than normal.

This drug is usually taken 30 minutes before chemotherapy starts.

Oral administration in the form of tablets or absorbable films or tablets

Oral liquid form

Administered intravenously (by drip or injection) in liquid form

• Headache
• Abdominal pain
• Dizziness
• Diarrhea
• Constipation
• Rash
• Increased fatigue or general weakness
• Blurred vision
• Alarm
• Disorders of the heart
• Liver disorders

The listed side effects are not observed in all patients who are prescribed ondansetron. The most common side effects are highlighted in bold, but others are not excluded. Report all possible side effects to your doctor or pharmacist.

Be sure to discuss these and other recommendations with your doctor or pharmacist.

Home use of ondansetron:

• Non-absorbable tablets should be swallowed whole. Do not crush or chew before taking.
• Resorbable tablets or films hold on tongue until completely dissolved. They should not be chewed or swallowed with water or other liquid. Hands must be dry when handling the preparation.
• When taking ondansetron in liquid form, measure the dosage using the measuring device included in the kit.
• Take your dose as soon as possible if you miss it. Do not do this only if there is little time left until the next appointment. In no case do not double the dose at the next dose!
• Store at room temperature. Ondansetron for intravenous administration should be stored in the refrigerator.
• Do not use an expired drug.
• Follow the instructions for disposal of the drug.

Additional information about ondansetron

• Cytochrome P450 2D6 (CYP2D6) and drugs

More about ondansetron

Antiemetics – articles on veterinary medicine from Svoi Doktor specialists

Vomiting is a common clinical sign in small animal veterinary practice. It requires a rational approach to treatment based primarily on suspected or established pathology. A complete and detailed history is required to examine an animal with vomiting. It is most important to distinguish vomiting from regurgitation, since their etiology, on which specific diagnostic tests depend, is different. Regurgitation is a passive process in which undigested food or saliva is ejected spontaneously under the influence of gravity, while vomiting is a reflex accompanied by signs of nausea, increased salivation and contractions of the abdominal muscles.

Maropitant. Trade name Serenia/ Cerenia

This drug acts as an antiemetic by blocking the neurokinin-1 (NK1) receptor. Neurokinin-1 is a neurotransmitter that initiates vomiting from the vomiting center. Although NK1 receptors are involved in other physiological and behavioral responses, no side effects associated with blockade of other receptors have been reported at doses used to control vomiting. Maropitant can inhibit vomiting that is stimulated by both central and peripheral sources mediated by acetylcholine, histamine, dopamine, and serotonin. The NK1 receptor is also involved in pain transmission (via substance P). Blockade of the NK1 receptor may have potential as an adjunctive treatment for some types of pain (eg, visceral pain), but there are currently no clinical studies demonstrating an analgesic effect from maropitant. [1], [2], [3], [7]

The drug effectively suppresses vomiting from chemotherapy, gastrointestinal diseases, intoxication, kidney disease, vestibular irritants (sickness). [4]

Adverse reactions: pain reaction during injection. Very high doses in cats can cause hemolysis. The injections should not be mixed with any other agent as there are no compatibility studies.

Maropitant is available as 16, 24, 60, or 160 mg tablets and 10 mg/mL injection. However, in the Russian Federation the tablet form is not available.

Dosage: dogs, cats: 1 mg/kg daily or 2 mg/kg orally every 24 hours. To prevent motion sickness in foreign literature, tablets are used at a dose of 8 mg / kg per day for a maximum of 2 days.

Metoclopramide. Trade name Cerucal/Reglan/Maxolon

Antiemetic and prokinetic drug. Metoclopramide stimulates upper gastrointestinal motility and is a centrally acting antiemetic. Among the proposed mechanisms are stimulation of 5-HT (serotonin) receptors or increased release of acetylcholine in the gastrointestinal tract. Affinity for 5-HT4 receptors is low compared to other more effective motility-modifying drugs. It inhibits dopamine-induced relaxation of the stomach, thus enhancing the cholinergic responses of gastric smooth muscle to increase motility. It also increases the tone of the lower esophageal sphincter. Metoclopramide acts centrally by inhibiting dopamine, which is responsible for the antiemetic effects. The antiemetic effect is achieved through its antidopamine (D2) action.

The main effect in dogs is its antiemetic properties. Because this drug transiently increases prolactin secretion, there has been interest in its use for the treatment of agalactia in animals, but its efficacy has not been determined. [5]

Adverse effects are associated with blockade of central dopaminergic receptors. Use in patients with epilepsy or diseases caused by obstruction of the gastrointestinal tract is unacceptable. [6]

Most commonly used for general antiemetic purposes, but doses up to 2 mg/kg have been used to prevent vomiting during cancer chemotherapy (higher doses may cause antiserotonin effects). [3]

Metoclopramide is available as 5 and 10 mg tablets, 1 mg/ml oral solution and 5 mg/ml injection in 2, 10 and 30 ml vials.

Dosage: 0.2-0.5 mg/kg every 6-8 hours IV, IM or orally. For antiemetic treatment in cancer chemotherapy, the dose used is up to 2 mg/kg per day.

Ondansetron. Trade name Latran/Emetron/Zofran/ Zofran

Ondansetron is an antiemetic drug in a class of drugs called serotonin antagonists. Like other drugs in this class, ondansetron works by inhibiting serotonin type 3 (5-HT3) receptors.

In cats, oral absorption is 32% from oral administration and 75% from subcutaneous administration. In dogs, it is much less bioavailable (less than 10%) after oral administration and has a shorter half-life of 30 minutes, raising questions about the clinical efficacy of ondansetron in dogs.

Only limited information is available on the efficacy of ondansetron in animals, but ondansetron has been found to be effective for treating chemotherapy vomiting in animals.