What is Zofran used for. How does ondansetron work. Is Zofran safe during pregnancy. What are the potential side effects of ondansetron. How should Zofran be taken. Are there any drug interactions with ondansetron. What precautions should be taken when using Zofran.

Understanding Zofran: A Comprehensive Overview

Zofran, also known by its generic name ondansetron, is a medication that belongs to a class of drugs called 5-HT3 receptor antagonists. It is primarily used to prevent and treat nausea and vomiting associated with various medical conditions and treatments. Zofran works by blocking the action of serotonin, a naturally occurring chemical in the body that can trigger nausea and vomiting.

Key Facts About Zofran

• Active ingredient: Ondansetron
• Drug class: 5-HT3 receptor antagonist
• Available forms: Tablets, oral solution, and injection
• Primary use: Prevention and treatment of nausea and vomiting

Medical Uses of Zofran: When Is It Prescribed?

Zofran is prescribed for several medical conditions and situations where nausea and vomiting are common symptoms. The primary uses of Zofran include:

1. Prevention of chemotherapy-induced nausea and vomiting
2. Management of radiation therapy-related nausea and vomiting
3. Prevention and treatment of postoperative nausea and vomiting

In some cases, healthcare providers may prescribe Zofran for off-label uses, such as managing severe morning sickness in pregnant women. However, this use is controversial and should be carefully considered due to potential risks.

How does Zofran work to prevent nausea and vomiting?

Zofran functions by selectively blocking serotonin receptors in the brain and gut. Serotonin is a neurotransmitter that can trigger the vomiting reflex when present in high concentrations. By inhibiting these receptors, Zofran effectively reduces the likelihood of nausea and vomiting in susceptible individuals.

Dosage and Administration of Zofran

The appropriate dosage of Zofran varies depending on the specific medical condition being treated, the patient’s age, and the form of the medication being used. It’s crucial to follow the prescribing physician’s instructions carefully.

Common Dosage Forms and Strengths

• Tablets: 4 mg, 8 mg
• Oral solution: 4 mg/5 mL
• Injection: 2 mg/mL

For chemotherapy-induced nausea and vomiting, a typical adult dose might be 8 mg taken orally 30 minutes before chemotherapy, followed by 8 mg 8 hours later, and then 8 mg twice daily for 1-2 days after chemotherapy. However, dosages can vary significantly based on individual factors and the specific chemotherapy regimen.

Can Zofran be taken on an empty stomach?

Zofran can be taken with or without food. However, if you experience stomach upset when taking the medication on an empty stomach, it may be helpful to take it with a small meal or snack. Always follow your healthcare provider’s specific instructions regarding administration.

Side Effects and Precautions of Ondansetron

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

Common Side Effects

• Headache
• Constipation
• Fatigue
• Dizziness
• Dry mouth

Serious Side Effects

While rare, some individuals may experience more severe side effects that require immediate medical attention:

• Irregular heartbeat
• Allergic reactions (rash, itching, swelling)
• Severe dizziness or fainting
• Signs of serotonin syndrome (agitation, hallucinations, rapid heartbeat, fever, muscle stiffness)

Are there any long-term side effects of taking Zofran?

Long-term studies on the effects of prolonged Zofran use are limited. While the medication is generally considered safe for short-term use, continuous long-term use should be monitored by a healthcare provider. Some studies have suggested a potential increased risk of cardiac arrhythmias with prolonged use, particularly at higher doses.

Zofran and Pregnancy: Safety Considerations

The use of Zofran during pregnancy is a topic of ongoing research and debate within the medical community. While it has been prescribed off-label for severe morning sickness, concerns about potential risks to fetal development have been raised.

Pregnancy Category

According to the US FDA pregnancy category system (which is no longer in use but provides historical context), Zofran was classified as Category B. This classification indicated that animal studies had not shown a risk to the fetus, but there were no adequate and well-controlled studies in pregnant women.

Current Recommendations

Current guidelines suggest that Zofran should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. The decision to use Zofran during pregnancy should be made on a case-by-case basis after careful consideration of the risks and benefits.

Does Zofran increase the risk of birth defects?

Some studies have suggested a potential link between Zofran use during early pregnancy and an increased risk of certain birth defects, particularly orofacial clefts. However, the evidence is mixed, and more research is needed to establish a definitive causal relationship. Pregnant women should discuss the potential risks and benefits of Zofran use with their healthcare provider.

Drug Interactions and Contraindications

Zofran can interact with various medications, potentially altering its effectiveness or increasing the risk of side effects. It’s crucial to inform your healthcare provider about all medications, supplements, and herbal products you are taking before starting Zofran.

Potential Drug Interactions

• Apomorphine: May increase the risk of severe hypotension and loss of consciousness
• QT-prolonging drugs: May increase the risk of cardiac arrhythmias
• Tramadol: May reduce the pain-relieving effects of tramadol
• Serotonergic drugs: May increase the risk of serotonin syndrome

Contraindications

Zofran is contraindicated in patients with known hypersensitivity to ondansetron or any component of the formulation. It should also be used with caution in patients with a history of QT interval prolongation or other cardiac rhythm disorders.

Can Zofran be taken with other anti-nausea medications?

In some cases, Zofran may be combined with other anti-nausea medications for enhanced effectiveness. However, this should only be done under the guidance of a healthcare provider, as certain combinations may increase the risk of side effects or drug interactions.

Alternatives to Zofran: Other Anti-Nausea Options

While Zofran is a widely used and effective anti-nausea medication, there are several alternatives available for those who cannot take ondansetron or for whom it is not effective.

Other 5-HT3 Receptor Antagonists

• Granisetron (Kytril)
• Palonosetron (Aloxi)
• Dolasetron (Anzemet)

Other Classes of Anti-Nausea Medications

• Dopamine antagonists (e.g., metoclopramide, promethazine)
• NK1 receptor antagonists (e.g., aprepitant)
• Antihistamines (e.g., meclizine, dimenhydrinate)
• Cannabinoids (e.g., dronabinol)

Are there any natural alternatives to Zofran for nausea relief?

Some individuals may prefer natural remedies for nausea relief. While these options may not be as potent as prescription medications, they can be effective for mild to moderate nausea:

• Ginger: Available in various forms, including tea, capsules, and candies
• Peppermint: Can be consumed as tea or in the form of essential oils
• Acupressure: Stimulating the P6 (Nei Kuan) point on the inner wrist
• Vitamin B6: May help with pregnancy-related nausea

It’s important to consult with a healthcare provider before using any natural remedies, especially during pregnancy or while undergoing medical treatments.

Monitoring and Follow-up While Taking Zofran

Regular monitoring is essential when taking Zofran, particularly for individuals on long-term therapy or those with pre-existing medical conditions. Your healthcare provider may recommend periodic check-ups and tests to ensure the medication is working effectively and to monitor for potential side effects.

Recommended Monitoring

• Electrolyte levels: Zofran can occasionally cause electrolyte imbalances
• Liver function tests: To monitor for potential hepatotoxicity
• ECG: For patients at risk of QT interval prolongation
• Regular assessment of nausea and vomiting control

When should you contact your healthcare provider while taking Zofran?

It’s important to contact your healthcare provider if you experience any of the following while taking Zofran:

• Severe or persistent side effects
• Lack of improvement in nausea and vomiting
• Signs of an allergic reaction
• Irregular heartbeat or palpitations
• Severe dizziness or fainting
• Any new or concerning symptoms

Prompt communication with your healthcare provider can help address any issues quickly and ensure the safe and effective use of Zofran.

Ondansetron Use During Pregnancy | Drugs.com

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Medically reviewed by Drugs.com. Last updated on Oct 3, 2022.

Ondansetron is also known as: Zofran, Zofran ODT, Zuplenz

Ondansetron Pregnancy Warnings

Use is not recommended (AU, UK)
This drug should be used during pregnancy only if clearly needed (US)

AU TGA pregnancy category: B1
US FDA pregnancy category: B

Comment:
-If use is absolutely necessary, caution should be exercised, especially during the first trimester.

Animal studies have failed to reveal evidence of harm to the embryo, fetus, gestation period, perinatal/postnatal development, and/or fertility. There are no controlled data in human pregnancy.

AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.

US FDA pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

See references

Ondansetron Breastfeeding Warnings

Breastfeeding is not recommended during use of this drug (AU, UK)
Use with caution (US)

Excreted into human milk: Unknown
Excreted into animal milk: Yes

Comments: The effects in the nursing infant are unknown.

See references

See also

• Ondansetron use while Breastfeeding (in more detail)
• Ondansetron Consumer Information
• Pregnancy Support Group
• FDA Pregnancy Categories
• Medicine use during Pregnancy
• Medicine use while Breastfeeding
• Safe Medications during Breastfeeding

References for pregnancy information

1. Product Information. Zofran (ondansetron). GlaxoSmithKline. 2001.
2. Cerner Multum, Inc. UK Summary of Product Characteristics.
3. Cerner Multum, Inc. Australian Product Information.
4. Product Information. Zuplenz (ondansetron). Strativa Pharmaceuticals, a Division of Par Pharmaceuticals, Inc. 2010.

References for breastfeeding information

1. Product Information. Zofran (ondansetron). GlaxoSmithKline. 2001.
2. Cerner Multum, Inc. UK Summary of Product Characteristics.
3. Cerner Multum, Inc. Australian Product Information.
4. Product Information. Zuplenz (ondansetron). Strativa Pharmaceuticals, a Division of Par Pharmaceuticals, Inc. 2010.
5. United States National Library of Medicine. Toxnet. Toxicology Data Network. http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT 2013.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

Zofran – Uses, Side Effects, Interactions

How does this medication work? What will it do for me?

Ondansetron belongs to the class of medications called 5-HT3 receptor antagonists.  This medication is used to prevent nausea and vomiting associated with certain types of cancer chemotherapy and radiation. It is also used to prevent and treat the nausea and vomiting that occurs after surgery. It works by reducing the effects of a naturally-occurring chemical in the body called serotonin, which causes nausea and vomiting.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Injection

Each mL contains ondansetron 2 mg/mL (as hydrochloride dihydrate) for IV use. Nonmedicinal ingredients: citric acid monohydrate, methyl- and propylparaben (vials only), sodium citrate, and sodium chloride.

Oral Solution

Each 5 mL contains ondansetron 4 mg (as hydrochloride dihydrate). Nonmedicinal ingredients: citric acid, sodium citrate dihydrate, sodium benzoate, sorbitol solution, and strawberry flavour. Sucrose-free. Sweetened with sorbitol.

Tablets

4 mg
Each oval-shaped, yellow, film-coated tablet, engraved “4” on one side and “GLAXO” on the other, contains ondansetron 4 mg (as hydrochloride dihydrate).  Nonmedicinal ingredients: lactose, magnesium stearate, hydroxypropyl methylcellulose, microcrystalline cellulose, opadry yellow or opaspray yellow (containing titanium dioxide and iron oxide yellow), and pregelatinized starch. Gluten- and tartrazine-free.

8 mg
Each oval-shaped, yellow, film-coated tablet, engraved “8” on one side and “GLAXO” on the other, contains ondansetron 8 mg (as hydrochloride dihydrate). Nonmedicinal ingredients: lactose, magnesium stearate, hydroxypropyl methylcellulose, microcrystalline cellulose, opadry yellow or opaspray yellow (containing titanium dioxide and iron oxide yellow), and pregelatinized starch. Gluten- and tartrazine-free.

Zofran ODT

4 mg
Each white, round, plano-convex, orally disintegrating tablet, with no markings on either side, contains ondansetron (base) 4 mg. Nonmedicinal ingredients: aspartame, gelatin, mannitol, sodium methyl hydroxybenzoate, sodium propyl hydroxybenzoate, and strawberry flavour.

8 mg
Each white, round, plano-convex, orally disintegrating tablet, with no markings on either side, contains ondansetron (base) 8 mg. Nonmedicinal ingredients: aspartame, gelatin, mannitol, sodium methyl hydroxybenzoate, sodium propyl hydroxybenzoate, and strawberry flavour.

How should I use this medication?

The recommended adult dose of ondansetron for nausea and vomiting caused by chemotherapy is based on severity of the symptoms and ranges from 8 mg to 24 mg daily given in divided doses.

Doses for children are based on body size. The recommended dose for children is 3 to 5 mg per square metre of body surface area and will be calculated by your doctor.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the one given here, do not change the way that you are taking the medication without consulting your doctor.

Ondansetron should be taken ½ to 1 hour before chemotherapy treatment. After this first dose, it should be taken every 8 to 12 hours for up to 5 days.

Use an oral syringe to measure each dose of the liquid, as it gives a more accurate measurement than household teaspoons.

Tablets should be swallowed whole, with fluids. Orally-dispersible tablets (ODTs) should be placed on the tongue and allowed to dissolve.

The recommended adult dose of ondansetron to treat and prevent nausea and vomiting caused by radiation therapy is 8 mg taken by mouth, 1 to 2 hours before treatment, and then every 8 hours for up to 5 days after treatment.

The recommended adult dose of ondansetron to prevent nausea and vomiting caused by surgery is 16 mg taken by mouth, 1 hour before anesthesia. Alternatively, a dose of 4 mg may be given by intravenous (into a vein) injection at the time of surgery. After surgery, a single dose of 4 mg of ondansetron may be given by intravenous injection to treat nausea or vomiting.

Ondansetron is not effective for treating or preventing nausea and vomiting caused by motion.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, and you do not feel sick, skip the missed dose and continue with your regular schedule. If you miss a dose and feel sick or vomit, take it as soon as possible and continue with your regular schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store all forms of this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

• are allergic to ondansetron or any ingredients of the medication
• are taking the medication apomorphine

What side effects are possible with this medication?

Many medications can cause side effects.  A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• constipation
• flushing or feeling warm
• hiccups
• low blood pressure
• unusual tiredness or weakness

Although most of the side effects listed below don’t happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blurred vision
• difficulty moving or abnormal body movement
• dizziness
• pain, redness, or burning at place of injection
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• signs of low potassium levels in the blood (e.g., weakness, fatigue, muscle cramps, irregular heartbeat)
• symptoms of irregular heartbeat (e.g., chest pain, dizziness, rapid, pounding heartbeat, shortness of breath)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• blindness
• seizures
• signs of a serious allergic reaction (i.e., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
• signs of heart problems (e. g., fast, irregular heartbeat or pulse, chest pain, sudden weight gain, difficulty breathing, leg swelling)
• signs of serotonin syndrome (e.g., agitation, confusion, mood changes, decreased coordination, hallucinations, fever, sweating)
• signs of a severe skin reaction (e.g., a rash combined with fever or discomfort, a rash covering a large area of the body, a rash that spreads quickly, blistering, peeling)
• signs of decreased blood flow to the heart muscle (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergy: People who have had an allergic reaction to dolasetron or granisetron are advised not to take ondansetron. Before you take ondansetron, inform your doctor about any previous adverse reactions you have had to medications. Contact your doctor at once if you experience signs of an allergic reaction such as skin rash, itching, difficulty breathing, or swelling of the face and throat.

Abnormal heart rhythms: Very rarely, ondansetron can affect the heart’s electrical activity and cause an irregular heartbeat. This is more likely to happen with the injectable form of ondansetron. Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, probucol, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with ondansetron. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease and abnormal heart rhythms, or are taking certain medications (e.g., verapamil, atazanavir), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may monitor your heart rate using a test called an electrocardiogram (ECG) while you are using this medication.

Heart problems: Ondansetron can cause blood vessels in the heart to spasm, reducing blood flow to parts of the heart. This can cause chest pain and in severe cases may cause areas of heart muscle to be damaged. If you experience chest pain, let your doctor know immediately.

Liver function: Ondansetron is broken down and removed from the body by the liver. Decreased liver function slows down the removal of the medication from the body and increases the risk of side effects from ondansetron. If you have liver disease or reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Motion sickness: Ondansetron is not effective for the treatment of motion sickness.

Neuroleptic malignant syndrome (NMS): Ondansetron, like other similar medications, can cause a potentially fatal syndrome known as neuroleptic malignant syndrome (NMS). If you notice the symptoms of NMS such as high fever, muscle stiffness, confusion or loss of consciousness, sweating, racing or irregular heartbeat, or fainting, get immediate medical attention.

Phenylketonuria: People with phenylketonuria (lacking the enzyme needed to break down phenylalanine) should take forms of ondansetron other than oral dissolving tablets (ODT). The ODT form of ondansetron contains aspartame, an ingredient that cannot be broken down in the body by people who have phenylketonuria.

Serotonin syndrome: Severe reactions are possible when ondansetron is combined with other medications that act on serotonin, such as tricyclic antidepressants and serotonin reuptake inhibitors, medications used to treat depression. These combinations should be avoided. Symptoms of a reaction may include muscle rigidity and spasms, difficulty moving, and changes in mental state including delirium and agitation. Coma and death are possible.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. Use of ondansetron during the first trimester of pregnancy can increase the risk of birth defects. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if ondansetron passes into breast milk. If you are breast-feeding and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication to treat nausea and vomiting caused by chemotherapy have not been established for children under 3 years of age. The safety and effectiveness of using this medication to treat nausea and vomiting caused by radiation or surgery have not been determined for children less than 18 years of age. Its use by this age group is not recommended.

Seniors: The safety and effectiveness of using this medication by people 65 years or older to treat nausea and vomiting caused by surgery have not been established. Seniors may be at an increased risk of developing irregular heartbeat with ondansetron, particularly the injectable form. Talk to your doctor about any concerns you may have.

What other drugs could interact with this medication?

There may be an interaction between ondansetron and any of the following:

• amiodarone
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, pimozide, quetiapine, risperidone)
• apalutamide
• apomorphine
• carbamazepine
• capecitabine
• CF transmembrane regulators (e.g., ivacaftor, lumacaftor)
• disopyramide
• domperidone
• dronedarone
• enzalutamide
• fentanyl
• flecainide
• fluconazole
• linezolid
• lithium
• macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
• meperidine
• metformin
• methadone
• mirtazapine
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, tranylcypromine)
• phenobarbital
• phenytoin
• primidone
• procainamide
• propafenone
• quinine
• quinolone antibiotics (e. g., levofloxacin, moxifloxacin)
• rifampin
• St. John’s wort
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline, vortioxetine)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
• sotalol
• tapentadol
• tramadol
• trazodone
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• tryptophan
• tyrosine kinase inhibitors (e.g., crizotinib, dabrafenib, dasatinib, nilotinib, ribociclib, sunitinib)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

All material copyright MediResource Inc. 1996 – 2023. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/drug/getdrug/Zofran

Antiemetics – veterinary articles from Svoy 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. [3], [5]

No adverse effects of ondansetron have been reported in animals. Important contraindications in animals have not been identified. Dose modification is not required in animals with renal insufficiency.

Ondansetron is available as 4 and 8 mg tablets and 2 mg/mL injections. Dosage for dogs and cats: 0.5-1 mg/kg 30 minutes before administration of chemotherapy drugs. Other causes of vomiting: 0. 2-0.3 mg/kg, slow intravenous injection and repeated every 6-12 hours. If there is no effect, increase to 0.5 mg / kg.

[1] De La Puente-Redondo, “Efficacy of maropitant for treatment and prevention of emesis caused by intravenous infusion of cisplatin in dogs”, 2007
[2] Vail, “Efficacy of injectable maropitant in a randomized clinical trial for prevention and treatment of cisplatin-induced emesis in dogs presented as veterinary patients”, 2011
[3] Valverde, “Effects of acepromazine on the incidence of vomiting associated with opioid administration in dog”, 2004
[4] Benchaoui, “Efficacy of maropitant for preventing vomiting associated with motion sickness in dogs”, 2007
[5] Hubbard, Risk of vomiting and diarrhoea in dogs, 2007
[6] Capak, Incidence of foreign-bodyinduced ileus in dogs, 2001
[7] Conder, Sedlacek, Boucher, “Efficacy and safety of maropitant, a selective neurokinin 1 receptor antagonist, in two randomized clinical trials for prevention of vomiting due to motion sickness in dogs”, 2008

Veterinarian
Volodin A. D.
SVK “Own Doctor” branch “Dzerzhinsky”

HOW TO TAKE ANTIEMOTICS WITH CHEMOTHERAPY

The mechanism of action of 5HT-3 antagonists: blocking receptors that are sensitive to serotonin secreted by the body. Due to this, nervous excitation does not enter the vomiting center. If they are arranged by efficiency, it will turn out like this: tropisetron (navoban), granisetron (kytril), ondansetron (zofran). Although in the clinic the effectiveness of granisetron may exceed the experimental one, therefore some researchers give the palm to granisetron. The fact is that granisetron lingers longer in the body and acts only on 5HT-3 receptors responsible for nausea. And ondansetron partially “disperses” its action, being distracted by both 5HT-1 and 5HT-2 receptors.

These drugs are administered intravenously over 30 minutes. – 1 hour before chemotherapy. If treatment is planned only with cytostatic tablets or capsules, then it is more reasonable to drink antiemetic tablets or capsules an hour in advance, you can insert a Zofran suppository into the rectum. There is no need to administer intravenous antiemetic in this situation – no benefit in efficacy. Another thing is if intravenous chemotherapy is supposed, then the introduction of an antiemetic into a vein through the same catheter, only half an hour or an hour earlier, is justified.

Granisetron and tropisetron act almost the same time from 8 to 12 hours, their effectiveness does not increase with increasing dose. That is, if it is not possible to prevent vomiting with one ampoule of medicine, it is useless to do the second.

Ondansetron is completely eliminated from the body after 3-5 hours, as the dose increases, the results improve, so it can be administered intravenously from 4 to 32 mg. The 32 mg dose is the standard dose to prevent the most severe vomiting. But the duration of the action is exactly the same, which is 4 mg, which is 32 mg. If ondansetron (Zofran, Latran, Emiset) was administered before chemotherapy, then after 4 hours, I recommend taking the medicine in tablets, even when you are not sick. Nausea is easier to prevent than to treat. In the case of preparation for chemistry with granisetron, the antiemetic should be repeated after 8 hours, without waiting for an attack. When using tropisetron, the capsule is drunk in the morning before meals. But there is absolutely no guarantee that you will not experience nausea on the day of chemotherapy, so you can take a tablet of ondansetron or granisetron before bed. It is better to “treat” nausea than to “under-treat”.

There are no drugs that have been completely harmless. So antiemetics can cause toxic reactions. All drugs of the 5HT-3 antagonist group act on intestinal activity: granisetron can cause constipation, tropisetron and ondansetron can cause diarrhea or constipation. The last two have an adverse effect on cardiac activity. To minimize the toxic reactions of antiemetics, it is necessary to strictly observe the intervals between doses and the maximum permitted doses: granisetron no more than 9mg per day for 2-3 times, ondansetron – up to 6 times in total 32 mg, tropisetron – 5 mg per day. And what if you continue to feel sick? Use drugs of other groups.

Dexamethasone is used concomitantly or sequentially to enhance the antiemetic effect of 5HT-3 antagonists. By the way, it is the combination of 5HT-3 antagonist + dexamethasone that is recognized as the standard of therapy. Be careful: dexamethasone is absolutely contraindicated in diabetes mellitus, gastric ulcer and arterial hypertension (popularly they say – arterial hypertension).

On the second day after chemotherapy, you can drink metoclopramide (cerucal, raglan), dimetpramide or domperidone (motilium). Metoclopramide or dimetpramide can reduce the emetogenic activity of chemotherapy drugs if administered before a cytostatic. Motilium should not be drunk before the introduction of cytostatics, since the mechanism of its action is such that, in principle, it cannot prevent such vomiting. But on the second day – it will go well. Try to limit yourself to four tricks, then unpleasant reactions from dizziness to hallucinations are very likely. Yes, yes, despite the fact that these drugs are sold without a prescription, they belong to the group of psychotropic drugs. Triethylperazine (Torecan) also belongs to this group, it is very convenient in rectal suppositories. It is better at night, and it will relieve nausea and calm sleep.

Antiemetics do not prevent preliminary nausea and vomiting. Since, it comes “from the mind” and is treated, therefore, it must be psychotropic. Previously, they were called “tranquilizers”, now – anxiolytics. You can not buy them yourself, only by prescription. Discuss this problem with the doctor, not in the sense of how to buy, but whether these drugs are needed or not. They are taken in very short courses, there is a danger of addiction.

Vomiting is not terrible in itself, as an extremely unpleasant condition, but due to dehydration. Loss of fluid is dangerous due to thickening of the blood, the formation of blood clots, difficulty in the work of the heart, and an increase in the concentration of toxic substances. Especially dangerous is vomiting in the heat with profuse sweating. Drinking is a must. You can’t eat – don’t eat, you won’t die of hunger, after that you will make up for everything. Fluid can be injected with droppers, but this is an extreme case. No matter how hard they try to bring solutions for intravenous administration as close as possible to the composition of body fluids natural for the body, this has not yet been possible. The drunk liquid will naturally pass into the composition of the blood, plasma and lymph. All necessary components will be synthesized. Drink tea, water, fruit drinks, kvass. Be careful with juices, the mucous membranes are damaged by chemotherapy drugs, the hour is uneven – you can drink up to diarrhea. Remember the original Russian drinks – uzvars from fruits and berries, where the concentration of fruit acids is much lower. And dried fruit compote, a longed-for childhood dream! Boil the pan before the course and refrigerate. You can make lemonade in the same way, of course, from a lemon.