Maropitant (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway. Before the advent of motorized transportation, they also provided accomm ...

; brand name: Cerenia, used as maropitant

citrate Citric acid is an organic compound with the formula . It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry Biochemistry, or biological chemistry, is the study of chemical processes within and relati ...

( USAN), is a neurokinin-1 (NK₁) receptor antagonist developed by Zoetis specifically for the treatment of

motion sickness Motion sickness occurs due to a difference between actual and expected motion. Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Complications may rarely include ...

and vomiting in dogs. It was approved by the FDA in 2007, for use in dogsPackage Insert for Cerenia at Pfizer Animal Health (full detailed drug information)
/ref> and in 2012, for cats. Maropitant mildly reduces intra-procedural inhaled anesthesia dose requirements but does not confer analgesia itself.

Veterinary uses

Injectable maropitant is used in

dogs The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers ...

to treat and prevent acute

vomiting Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteritis, pre ...

; tablets are used for preventing vomiting from a variety of causes, though it requires a higher dose to prevent vomiting from

. The injectable version is also licensed for preventing and treating acute vomiting in

cats The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...

. Maropitant is effective in treating vomiting from a variety of causes, including

gastroenteritis Gastroenteritis, also known as infectious diarrhea, is an inflammation of the Human gastrointestinal tract, gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of ...

chemotherapy Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents or alkylating agents) in a standard chemotherapy re ...

, and

kidney failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...

; when given beforehand, it can prevent vomiting caused by using an

opioid Opioids are a class of Drug, drugs that derive from, or mimic, natural substances found in the Papaver somniferum, opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, ...

as a

premedication Premedication is using medication before some other therapy (usually surgery or chemotherapy) to prepare for that forthcoming therapy. Typical examples include premedicating with a sedative or analgesic before surgery; using prophylactic (preven ...

. Some have claimed that maropitant is better at treating vomiting than nausea, pointing to cats with

chronic kidney disease Chronic kidney disease (CKD) is a type of long-term kidney disease, defined by the sustained presence of abnormal kidney function and/or abnormal kidney structure. To meet criteria for CKD, the abnormalities must be present for at least three mo ...

who, when receiving maropitant, had a reduction in vomiting but no corresponding increase in

appetite Appetite is the desire to eat food items, usually due to hunger. Appealing foods can stimulate appetite even when hunger is absent, although appetite can be greatly reduced by satiety. Appetite exists in all higher life-forms, and serves to reg ...

. Maropitant has been used in acute cases of

rapid Rapid(s) or RAPID may refer to: Hydrological features * Rapids, sections of a river with turbulent water flow * Rapid Creek (Iowa River tributary), Iowa, United States * Rapid Creek (South Dakota), United States, namesake of Rapid City Sport ...

labored breathing Labored respiration or labored breathing is an abnormal respiration characterized by evidence of increased effort to breathe, including the use of accessory muscles of respiration, stridor, grunting, or nasal flaring. Classification Labored br ...

to prevent vomiting that could lead to

aspiration pneumonia Aspiration pneumonia is a type of lung infection that is due to a relatively large amount of material from the stomach or mouth entering the lungs. Signs and symptoms often include fever and cough of relatively rapid onset. Complications may incl ...

. It has been given in combination with a

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant, depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed t ...

to cats prior to stressful events (such as a veterinary visit) to possibly relieve hypersensitivity. When compared to other

antiemetic An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer. They may ...

s, maropitant has similar or greater effectiveness to

chlorpromazine Chlorpromazine (CPZ), marketed under the brand names Thorazine and Largactil among others, is an antipsychotic medication. It is primarily used to treat psychotic disorders such as schizophrenia. Other uses include the treatment of bipolar d ...

and

metoclopramide Metoclopramide is a medication used to treat nausea, vomiting, gastroparesis, and gastroesophageal reflux disease. It is also used to treat migraine headaches. Common side effects include feeling tired, diarrhea, akathisia, and tardive dyski ...

for centrally mediated vomiting induced by apomorphine or

xylazine Xylazine is a structural analog of clonidine and an α2-adrenergic receptor, α2-adrenergic receptor agonist, sold under many trade names worldwide, most notably the Bayer brand name Rompun, as well as Anased, Sedazine and Chanazine. Xylazine ...

. It works better than chlorpromazine and metoclopramide for vomiting peripherally induced induced with

syrup of ipecac Syrup of ipecac (), or simply ipecac, is a drug that was once widely used as an expectorant (in low doses) and a rapid-acting emetic (in higher doses). It is obtained from the dried rhizome and roots of the ipecacuanha plant ('' Carapichea ipe ...

. Unlike

dimenhydrinate Dimenhydrinate, also known as diphenhydramine/8-chlorotheophylline salt and sold under the brand names Dramamine and Gravol, among others, is an over-the-counter medication used to treat motion sickness and nausea. Dimenhydrinate is a theocl ...

and

acepromazine Acepromazine, acetopromazine, or acetylpromazine (commonly known as ACP, Ace, or by the trade names Atravet or Acezine 2, number depending on mg/ml dose) is a phenothiazine derivative antipsychotic drug. It was used in humans during the 1950s as ...

, which are used for motion sickness, maropitant does not cause sedation. Maropitant has been used as an adjunct treatment in severe

bronchitis Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. ...

due to its weak anti-inflammatory effects. It alleviates

visceral pain Visceral pain is defined as pain that results from the activation of nociceptors of the thoracic, pelvic, or abdominal viscera (organs) in the human body. Visceral structures are highly sensitive to distension (stretch), ischemia and inflammation, ...

and has been found to reduce the amount of general anesthesia (both

sevoflurane Sevoflurane, sold under the brand name Sevorane, among others, is a sweet-smelling, nonflammable, highly fluorinated methyl isopropyl ether used as an inhalational anaesthetic for induction and maintenance of general anesthesia. After desflu ...

and

isoflurane Isoflurane, sold under the brand name Forane among others, is a halogenated ether used as a general anesthetic. It can be used to start or maintain anesthesia; however, other medications are often used to start anesthesia, due to airway irritat ...

) needed in some operations. Some believe that maropitant can be used in

rabbits Rabbits are small mammals in the family Leporidae (which also includes the hares), which is in the order Lagomorpha (which also includes pikas). They are familiar throughout the world as a small herbivore, a prey animal, a domesticated form ...

and

guinea pigs The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy ( ), is a species of rodent belonging to the genus ''Cavia'', family Caviidae. Breeders tend to use the name "cavy" for the animal, but "gui ...

to relieve pain caused by

ileus Ileus is a disruption of the normal propulsive ability of the intestine. It can be caused by lack of peristalsis or by mechanical obstruction. The word 'ileus' derives . The term 'subileus' refers to a partial obstruction. Signs and symptoms S ...

(impaired bowel movements), though it lacks antiemetic effects in rabbits, who cannot vomit. Maropitant is given orally,

subcutaneously The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, or superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and m ...

, and

intravenously Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutr ...

Contraindications

Maropitant is only indicated for dogs at least 16 weeks old, as some very young puppies suffered bone marrow

hypoplasia Hypoplasia (; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ. It should also be used with caution in animals with suspected GI obstruction or toxin ingestion, as it can mask symptoms, thereby delaying the diagnosis. It is not recommended to give maropitant for more than five consecutive days, as it tends to accumulate in the body due to one of the liver enzymes responsible for its metabolism, CYP2D15, becoming saturated. However, there have been studies where beagles who were given maropitant for two weeks in a row showed no signs of toxicity. Because maropitant is metabolized by the liver, caution should be taken when giving it to dogs with liver dysfunction. Caution should also be taken when giving it with other drugs that are also highly protein-bound, such as NSAIDs,

anticonvulsants Anticonvulsants (also known as antiepileptic drugs, antiseizure drugs, or anti-seizure medications (ASM)) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also used in the treatment ...

, and some behavior-modifying drugs; such drugs compete with maropitant for binding to plasma proteins, increasing the concentration of unbound maropitant in the blood. Maropitant should also not be used with calcium channel antagonists (used to treat high blood pressure) or in animals with

heart disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...

, as it has a slight affinity for

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

and

potassium channels Potassium channels are the most widely distributed type of ion channel found in virtually all organisms. They form potassium-selective pores that span cell membranes. Potassium channels are found in most cell types and control a wide variety of ...

Side effects

Maropitant is safer than other antiemetics used in veterinary medicine, in part because of its high specificity for its target and thus not binding to other receptors in the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

. Side effects in dogs and cats include

hypersalivation Hypersalivation or hypersialosis is the excessive production of saliva. It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva.Medscape > HypersalivationBy Erica Brownfield. P ...

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

loss of appetite Anorexia is a medical term for a loss of appetite. While the term outside of the scientific literature is often used interchangeably with anorexia nervosa, many possible causes exist for a loss of appetite, some of which may be harmless, while o ...

, and

. Eight percent of dogs taking maropitant at doses meant to prevent motion sickness vomited right after, likely due to the local effects maropitant had on the gastrointestinal tract. Small amounts of food beforehand can prevent such post-administration vomiting. One of the most common side effects of subcutaneous administration is moderate to severe pain at the injection site. Although the manufacturer recommends keeping maropitant at room temperature, many people have noted that keeping it in the fridge reduces the sting upon injection. Only unbound maropitant causes pain – it is normally formulated with beta-cyclodextrin to increase solubility; at cooler temperatures, more of the maropitant remains bound to the cyclodextrin, leaving less maropitant unbound. While there is no pain related to the intravenous administration of maropitant, pushing a dose in too quickly can temporarily reduce blood pressure. Fewer than 1 in 10,000 dogs and cats experience anaphylactic reactions.

Overdose

Signs of maropitant overdose include

lethargy Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overw ...

, irregular or labored breathing, lack of muscle coordination, and tremors. Overdose of the oral formulation can cause

salivation Saliva (commonly referred as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DN ...

and nasal discharge, while overdose of intravenous maropitant can sometimes lead to reddish urine. The LD₅₀ is high, being over 2,000 mg/kg for oral maropitant in rats. Injectable Cerenia

Pharmacology

Mechanism of action

Vomiting is caused when impulses from the

chemoreceptor trigger zone The chemoreceptor trigger zone (CTZ) is an area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with other structures in the vomiting center to initiate vomiting. The CTZ is located within the are ...

(CRTZ) in the brain are sent to the

vomiting center The area postrema, a paired structure in the medulla oblongata of the brainstem, is a circumventricular organ having permeable capillaries and sensory neurons that enable its role to detect circulating chemical messengers in the blood and transdu ...

in the

medulla Medulla (Latin for "marrow") or medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ...

. Motion sickness specifically occurs when signals to the CRTZ originate from the

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

: motion is sensed by the fluid of the

semicircular canals The semicircular canals are three semicircular interconnected tubes located in the innermost part of each ear, the inner ear. The three canals are the lateral, anterior and posterior semicircular canals. They are the part of the bony labyrinth, ...

, which causes overstimulation. The signal travels to the brain's

vestibular nuclei The vestibular nuclei (VN) are the cranial nuclei for the vestibular nerve located in the brainstem. In Terminologia Anatomica, they are grouped in both the pons and the medulla in the brainstem The brainstem (or brain stem) is the poste ...

, then to the CRTZ, and finally to the vomiting center. Maropitant has a similar structure to

substance P Substance P (SP) is an undecapeptide (a peptide composed of a chain of 11 amino acid residues) and a type of neuropeptide, belonging to the tachykinin family of neuropeptides. It acts as a neurotransmitter and a neuromodulator. Substance P ...

, the key neurotransmitter in causing vomiting, which allows it to act as an

antagonist An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.neurokinin 1 The tachykinin receptor 1 (TACR1) also known as neurokinin 1 receptor (NK1R) or substance P receptor (SPR) is a G protein coupled receptor found in the central nervous system and peripheral nervous system. The endogenous ligand for this receptor ...

(NK₁). It is highly selective for NK₁ over NK₂ and NK₃. Maropitant binds to the neurokinin receptors in the

vagus nerves The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibers ...

leaving the GI tract, as well as to receptors in the CRTZ and the vomiting center. By virtue of working at the last step in triggering vomiting, it can prevent a broader range of stimuli than most antiemetics can. It is effective against emetogens that act at the

(such as apomorphine in dogs and

in cats), those that act in the periphery (e.g.

), and those that act in both (e.g.

cisplatin Cisplatin is a chemical compound with chemical formula, formula ''cis''-. It is a coordination complex of platinum that is used as a chemotherapy medication used to treat a number of cancers. These include testicular cancer, ovarian cancer, c ...

Pharmacokinetics

Maropitant's

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

is unaffected by the presence of food. Bioavailability is 91% at the standard subcutaneous dose but 24% at the standard oral dose; the standard oral dose is higher to partially compensate for incomplete bioavailability. It binds to plasma proteins at a rate of 99.5%; it has a low volume of distribution (9 L/kg) and is thus not extensively absorbed. Subcutaneously administered maropitant had peak plasma concentration around half an hour after administration; the mean half-life is 6–8 hours, and a single dose lasts 24 hours in dogs. Orally administered maropitant reached its peak plasma concentration within two hours. Maropitant undergoes 1st-pass metabolism by liver enzymes, mainly CYP2D15 (which has high affinity for maropitant and clears over 90% of it) but also by the lower-affinity CYP3A12. Repeat dosing of maropitant eventually saturates CYP2D15, causing the drug to accumulate due to reduced clearance. Thus, it is recommended to not use maropitant for more than five days straight, and to have a two-day rest period to allow maropitant to clear the body to prevent accumulation. Maropitant has over 21 metabolites, though its major one (produced by

hydroxylation In chemistry, hydroxylation refers to the installation of a hydroxyl group () into an organic compound. Hydroxylations generate alcohols and phenols, which are very common functional groups. Hydroxylation confers some degree of water-solubility ...

) is CJ-18,518. Maropitant clearance is slower in cats.

Society and culture

Legal status

In February 2025, the

Committee for Veterinary Medicinal Products The Committee for Veterinary Medicinal Products (CVMP) is the European Medicines Agency's committee responsible for elaborating the agency's opinions on all issues regarding veterinary medicines. Text was copied from this source which is copyrigh ...

(CVMP) of the

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of pharmaceutical products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products ...

adopted a positive opinion, recommending the granting of a marketing authorization for the veterinary medicinal product Elmaro for cats and dogs. The applicant for this veterinary medicinal product is Elanco GmbH. Elmaro is a generic of Cerenia, which has been authorized in the EU since June 2006. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. In April 2025, the CVMP adopted a positive opinion, recommending the granting of a marketing authorization for the veterinary medicinal product Emevet, chewable tablet, intended for dogs. The applicant for this veterinary medicinal product is CP-Pharma Handelsgesellschaft mbH. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.

References

External links

FDA: Adverse Drug Experience (ADE) Reports: See Maropitant (multiple sections, p. 121-152)
{{Authority control Cat medications Dog medications NK1 receptor antagonists Phenol ethers Quinuclidines Tert-butyl compounds