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: An Effective Antiemetic Medication

Zofran, also known by its generic name ondansetron, is a powerful prescription medication used to combat nausea and vomiting. It belongs to a class of drugs called 5-HT3 receptor antagonists, which work by blocking the action of serotonin in the body. This mechanism effectively prevents the triggering of nausea and the initiation of the vomiting reflex.

Primarily, Zofran is prescribed for patients undergoing cancer treatments such as chemotherapy and radiation therapy. It’s also commonly used to prevent post-operative nausea and vomiting. The drug comes in various forms, including oral tablets, orally disintegrating tablets, oral films, oral solution, and injection vials, catering to different patient needs and preferences.

Dosage Guidelines: How Much Zofran Should You Take?

The appropriate dosage of Zofran varies depending on the specific condition being treated, the patient’s age, and the severity of symptoms. Here’s a breakdown of typical dosage recommendations:

For Adults:

• Severe chemotherapy-induced nausea: A single 24 mg dose taken 30 minutes before treatment
• Moderate chemotherapy-induced nausea: 8 mg taken 30 minutes before treatment, followed by another 8 mg dose 8 hours later
• Radiation therapy: 8 mg taken 1-2 hours before treatment, followed by 8 mg every 8 hours as needed
• Post-operative nausea: 16 mg administered 1 hour before anesthesia

For Children:

• Ages 4-11: 4 mg taken 30 minutes before chemotherapy, with additional doses at 4 and 8 hours after the initial dose
• Ages 12-17: 8 mg taken 30 minutes before chemotherapy, with an additional dose 8 hours later

It’s crucial to note that these are general guidelines, and your healthcare provider may adjust the dosage based on your individual needs and response to the medication.

Frequency of Use: How Often Can You Take Zofran?

The frequency of Zofran use is an important consideration for effective symptom management. Is it safe to take Zofran more frequently than every 8 hours? Generally, the recommended dosing schedule for adults is 8 mg every 8-12 hours, or 2-3 times per day. However, in some cases, more frequent dosing may be necessary.

For instance, children undergoing chemotherapy may receive doses at 4-hour intervals initially, followed by doses every 8 hours for 1-2 days after treatment. It’s important to emphasize that patients should never exceed the prescribed dosage or frequency without consulting their healthcare provider.

Potential Side Effects and Precautions

While Zofran is generally well-tolerated, it can cause side effects in some patients. Common side effects may include:

• Headache
• Constipation
• Fatigue
• Dizziness
• Dry mouth

More severe side effects, though rare, can include allergic reactions, irregular heartbeat, and serotonin syndrome. Patients should be aware of these potential risks and report any unusual symptoms to their healthcare provider immediately.

Are there any precautions to consider when taking Zofran? Indeed, certain groups should exercise caution:

• Patients with severe liver disease should not exceed 8 mg per day
• Pregnant women should consult their doctor before use, as Zofran is not FDA-approved for pregnancy
• Children under 4 years old should not be given Zofran
• Patients with a history of Long QT syndrome should avoid Zofran

Drug Interactions: What to Watch Out For

Zofran can interact with various medications, potentially altering its effectiveness or increasing the risk of side effects. Some notable interactions include:

• Apomorphine: Can cause severe hypotension and loss of consciousness
• Tramadol: May reduce the pain-relieving effects of tramadol
• Selective Serotonin Reuptake Inhibitors (SSRIs): Can increase the risk of serotonin syndrome
• Certain heart medications: May increase the risk of QT interval prolongation

Always inform your healthcare provider about all medications, supplements, and herbal products you’re taking to avoid potential interactions.

Maximizing Zofran’s Effectiveness: Tips for Optimal Use

To get the most benefit from Zofran, consider the following tips:

1. Take the medication exactly as prescribed
2. If using the orally disintegrating tablet, allow it to dissolve on your tongue rather than swallowing it whole
3. Stay hydrated, especially if you’re experiencing vomiting
4. Keep track of your symptoms and communicate any changes to your healthcare provider
5. Store the medication at room temperature, away from moisture and heat

By following these guidelines, you can help ensure that Zofran works effectively to manage your nausea and vomiting symptoms.

Alternative Treatments: When Zofran Isn’t the Right Choice

While Zofran is highly effective for many patients, it may not be suitable for everyone. In such cases, alternative antiemetic medications or treatment approaches may be considered. Some alternatives include:

• Other 5-HT3 receptor antagonists like granisetron or palonosetron
• Dopamine antagonists such as metoclopramide or domperidone
• NK1 receptor antagonists like aprepitant
• Non-pharmacological approaches such as acupressure or ginger supplements

The choice of alternative treatment will depend on the underlying cause of nausea and vomiting, individual patient factors, and the healthcare provider’s clinical judgment.

Long-term Use of Zofran: What You Need to Know

Zofran is primarily intended for short-term use in managing acute nausea and vomiting. However, in some cases, such as ongoing cancer treatment, longer-term use may be necessary. Are there any concerns associated with prolonged Zofran use?

While Zofran is generally safe for extended periods when used as directed, long-term use may increase the risk of certain side effects. These can include constipation, headaches, and in rare cases, changes in heart rhythm. Regular monitoring by a healthcare provider is essential for patients on long-term Zofran therapy.

Additionally, it’s important to periodically reassess the need for continued Zofran use. As underlying conditions change or improve, it may be possible to reduce or discontinue the medication under medical supervision.

Zofran in Special Populations: Pediatric and Geriatric Use

Zofran’s use in special populations, such as children and the elderly, requires careful consideration. How does Zofran’s efficacy and safety profile differ in these groups?

Pediatric Use:

Zofran is approved for use in children as young as 4 years old for chemotherapy-induced nausea and vomiting. However, dosing must be carefully adjusted based on the child’s age and weight. It’s important to note that Zofran is not approved for use in children under 4 years of age.

Studies have shown that Zofran is generally well-tolerated in children, with a side effect profile similar to that seen in adults. However, parents and caregivers should be vigilant for any unusual reactions and report them promptly to the child’s healthcare provider.

Geriatric Use:

Elderly patients may be more sensitive to the effects of Zofran, particularly its impact on heart rhythm. As such, lower initial doses may be recommended, with careful monitoring for side effects. Additionally, age-related changes in kidney or liver function may necessitate dose adjustments.

Despite these considerations, Zofran remains an effective option for managing nausea and vomiting in older adults, particularly in the context of cancer treatment or post-operative care.

The Future of Antiemetic Therapy: Beyond Zofran

While Zofran has been a mainstay of antiemetic therapy for decades, ongoing research continues to explore new approaches to managing nausea and vomiting. What emerging treatments or strategies are on the horizon?

• Novel drug formulations: Researchers are developing new delivery methods for antiemetic drugs, including long-acting injections and transdermal patches, which could provide more convenient and consistent symptom control.
• Combination therapies: Studies are investigating the potential benefits of combining different classes of antiemetic drugs to achieve better symptom control with fewer side effects.
• Personalized medicine approaches: Genetic testing may help identify patients who are most likely to respond to specific antiemetic medications, allowing for more tailored treatment strategies.
• Non-pharmacological interventions: There is growing interest in complementary approaches such as acupuncture, mindfulness techniques, and virtual reality therapy as adjuncts to traditional antiemetic medications.

As our understanding of the mechanisms underlying nausea and vomiting continues to evolve, it’s likely that new and improved treatment options will emerge, potentially offering even better symptom control and quality of life for patients.

Conclusion: Zofran as a Valuable Tool in Symptom Management

Zofran (ondansetron) remains a crucial medication in the management of nausea and vomiting, particularly in the context of cancer treatment and post-operative care. Its mechanism of action, blocking serotonin receptors, provides effective relief for many patients struggling with these challenging symptoms.

While the typical dosing schedule involves taking Zofran every 8 hours, individual needs may vary, and healthcare providers may adjust the frequency based on specific circumstances. It’s essential for patients to follow their prescribed regimen closely and communicate any concerns or persistent symptoms to their healthcare team.

As with any medication, Zofran carries potential risks and side effects, making it crucial for patients to be well-informed about its proper use, potential interactions, and warning signs of adverse reactions. By working closely with healthcare providers and adhering to recommended guidelines, patients can maximize the benefits of Zofran while minimizing potential risks.

As research in the field of antiemetic therapy continues to advance, it’s likely that new treatment options and strategies will emerge, potentially offering even more effective and personalized approaches to managing nausea and vomiting. However, for now, Zofran remains a valuable and widely-used tool in the arsenal against these debilitating symptoms, improving quality of life for countless patients worldwide.

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.