Q: What are the common side effects of Cerenia?

The most common side effect is pain at the injection site. Other potential effects include changes in gastrointestinal motility (slowed peristalsis) and subtle ECG changes. Sedation is not commonly reported, but it may have additive effects with anesthetics.

# Cerenia Maropitant: Vomiting and Motion Sickness Dose Calculator ## Key Takeaways - Cerenia (maropitant citrate) is a neurokinin-1 (NK-1) receptor antagonist that blocks substance P, inhibiting both centrally and peripherally mediated vomiting. - Standard labeled doses for dogs include 1 mg/kg subcutaneously (SC) or 2 mg/kg orally (PO) for acute vomiting, and 8 mg/kg PO for motion sickness. For cats, the labeled dose is 1 mg/kg SC for vomiting, with oral use being off-label. - Injection-site discomfort is a common adverse effect with SC maropitant in dogs, occurring in over 60% of cases in one study. - Maropitant's mechanism of action on substance P suggests potential analgesic properties and effects on gastrointestinal motility, with research exploring its use in perioperative pain management and its impact on peristalsis. - Contraindications include suspected gastrointestinal obstruction, hypersensitivity, and caution is advised in patients with severe hepatic dysfunction or pre-existing cardiac disease due to potential subtle ECG changes. - Maropitant is not a universal antiemetic and may be less effective against vomiting triggered by certain chemoreceptor trigger zone stimuli that rely on dopamine or serotonin pathways, necessitating a thorough diagnostic workup for refractory or chronic vomiting. --- **Direct answer:** For a [dog](/knowledge/veterinary-medicine/clinical-methods/dog), the standard Cerenia (maropitant citrate) dose for acute vomiting is 1 mg/kg given subcutaneously once daily, or 2 mg/kg given orally once daily. For motion sickness in dogs, the oral dose is 8 mg/kg once daily. For cats, the labeled dose is 1 mg/kg subcutaneously once daily for vomiting; oral use is off-label but common. This article provides a practical calculator guide, safety boundaries, and evidence-based context for veterinarians and pet owners. **Owner triage summary:** If your pet vomits once and is otherwise bright, eating, and hydrated, contact your veterinary clinic for advice before medicating. Do not give Cerenia if your pet has ingested a toxin, a foreign body, or shows signs of abdominal pain, lethargy, or repeated vomiting with diarrhoea. Cerenia is a prescription medication. The correct dose depends on species, route, and indication. Never use a canine dose in a [cat](/knowledge/veterinary-medicine/clinical-methods/cat), and never use a feline dose in a dog. When in doubt, seek veterinary attention immediately. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## At a Glance: Cerenia Dose Reference Table The table below summarizes labeled and common clinical doses. Always confirm with your veterinarian. The evidence base is strongest for dogs and cats; other species are based on emerging research. | Species | Indication | Route | Dose | Frequency | Notes | |, - |, - |, - |, - |, - |, - | | Dog | Acute vomiting (prevention and treatment) | Subcutaneous (SC) | 1 mg/kg | Once daily | Labeled dose [1][2] | | Dog | Acute vomiting (prevention and treatment) | Oral (PO) | 2 mg/kg | Once daily | Labeled dose | | Dog | Motion sickness | Oral (PO) | 8 mg/kg | Once daily | Labeled dose; give 1-2 hours before travel | | Cat | Vomiting (prevention and treatment) | Subcutaneous (SC) | 1 mg/kg | Once daily | Labeled dose [3][4] | | Cat | Vomiting (off-label oral use) | Oral (PO) | 1-2 mg/kg | Once daily | Discuss with your veterinarian | | Rabbit | Perioperative pain management (research) | Subcutaneous (SC) | 2-4 mg/kg | Single dose | Research setting [5] | | Parrot (Orange-winged Amazon) | Extrapolated antiemetic (research) | SC or IV | 1 mg/kg | Single dose | Pharmacokinetic study [6] | | Macaque (non-human primate) | Emesis prevention (research) | Oral (PO) | 2 mg/kg | Single dose | Research setting [7] | **Key clinical point:** Injection-site discomfort is common with subcutaneous maropitant in dogs. In one randomized trial, 64.5% of dogs showed discomfort after injection, compared to 21.4% with dimenhydrinate and 7.1% with saline [1]. This is transient but should be anticipated, especially in anxious patients. ## Understanding Cerenia (Maropitant Citrate) Cerenia is the brand name for maropitant citrate, a neurokinin-1 (NK-1) receptor antagonist. Its primary mechanism is to block the action of substance P, a neuropeptide involved in the vomiting reflex and in pain signaling [8][9]. By binding to NK-1 receptors in the central nervous system and the gastrointestinal tract, maropitant inhibits both centrally mediated vomiting (such as motion sickness) and peripherally mediated vomiting (such as that caused by gastroenteritis or toxins) [8][9]. Maropitant is approved for use in dogs and cats in many regions, including North America, Europe, and Australia. It is widely used in veterinary practice for the prevention and treatment of acute emesis, motion sickness, and nausea associated with various conditions. **Important distinction:** Maropitant is not a universal antiemetic. It does not block all emetic pathways. For example, it is less effective against vomiting triggered by certain chemoreceptor trigger zone stimuli that rely on dopamine or serotonin pathways. In cases where vomiting is refractory, a multimodal approach may be needed. For example, a study on a dog with presumptive cyclic vomiting syndrome showed that vomiting did not respond to maropitant, ondansetron, or metoclopramide alone [10]. This highlights the need for a thorough diagnostic workup in chronic or recurrent cases. ## Mechanism of Action and Clinical Implications Maropitant's selectivity for NK-1 receptors is what makes it effective for both visceral and central emetic stimuli. The vomiting reflex is complex, involving the chemoreceptor trigger zone (CRTZ), the vomiting center, and the gastrointestinal tract. Substance P is a key neurotransmitter at multiple points in this pathway. - **Central action:** In the brainstem, substance P acts on NK-1 receptors in the nucleus tractus solitarius and the area postrema (the CRTZ). Maropitant crosses the blood-brain barrier and blocks these receptors, reducing the sensation of nausea and the vomiting response to motion, metabolic toxins, and certain drugs [8]. - **Peripheral action:** In the gastrointestinal tract, substance P is involved in local reflex arcs that trigger vomiting in response to irritation, inflammation, or distension. Maropitant also acts locally to reduce these signals [9]. **Clinical implication for dosing:** Because maropitant is a competitive antagonist, the dose and route matter for achieving adequate receptor occupancy. The labeled doses have been established to provide sufficient plasma concentrations to block NK-1 receptors for 24 hours in dogs and cats. ## Evidence-Based Efficacy: What the Studies Show The clinical use of maropitant is supported by a growing body of peer-reviewed research. The following sections summarize key findings from recent studies. ### Efficacy in Dogs: Preoperative and Anesthetic-Related Emesis A randomized, blinded, placebo-controlled trial evaluated the effectiveness of maropitant (1 mg/kg SC) compared to dimenhydrinate (4 mg/kg IM) and placebo in preventing emesis in dogs premedicated with hydromorphone and dexmedetomidine [1]. The study found that the incidence of vomiting/retching was significantly lower in the maropitant group (0/31 dogs) compared to the other groups. However, the incidence of nausea (ptyalism, lip licking, swallowing) was not significantly different between groups, suggesting that while maropitant effectively blocks the physical act of vomiting, it may not fully eliminate the sensation of nausea [1]. This is a crucial point for owners: a dog may still feel nauseous and exhibit signs like lip licking even if it does not vomit. ### Efficacy in Cats: Dexmedetomidine-Induced Vomiting Two studies have investigated the use of maropitant in cats to prevent vomiting induced by dexmedetomidine, a common sedative. - In a 2025 study, maropitant (1 mg/kg SC) was compared to ondansetron (0.22 mg/kg IM), metoclopramide (1 mg/kg IM), and saline in 64 cats [3]. All three antiemetics significantly reduced the duration and severity of vomiting and retching compared to saline. There was no significant difference in efficacy among the three drugs [3]. - Another 2025 study compared maropitant (1 mg/kg) to butorphanol (0.2 mg/kg) in combination with dexmedetomidine in cats undergoing ovariohysterectomy [4]. The incidence of emesis was very low in both groups (0/10 for butorphanol, 1/10 for maropitant). Interestingly, pain scores were significantly lower in the maropitant group, suggesting a potential analgesic benefit [4]. ### Beyond the Label: Analgesic and Gastrointestinal Effects Maropitant's mechanism of action on substance P has led to investigation of its analgesic properties, particularly for visceral pain. - A 2023 study in dogs undergoing ovariectomy compared maropitant (1 mg/kg IV) to methadone (0.3 mg/kg IV) [11]. The study found that maropitant produced analgesia and reduced the requirement of desflurane (an inhalant anesthetic) in amounts similar to methadone, without significant differences in cardiorespiratory variables. The authors suggested that maropitant may be recommended as part of a balanced anesthesia protocol [11]. - A 2026 study examined the effect of maropitant on gastrointestinal motility in healthy dogs [9]. The study found a significant decrease in the rate of peristalsis in the pylorus and jejunum after a 1 mg/kg SC dose. There was no significant change in intestinal diameter or wall thickness. This suggests that maropitant can slow gastric emptying and intestinal transit, which may be relevant in cases of suspected ileus or obstruction [9]. - In a rat model of neuropathic pain, maropitant demonstrated a reduction in oxidative stress, endoplasmic reticulum stress, and neuroinflammation [12]. While this is preclinical data, it supports the hypothesis that maropitant has effects beyond simple antiemesis. ### Emerging Evidence in Other Species While maropitant is labeled for dogs and cats, research is exploring its use in other species. - **Rabbits:** A 2024 study evaluated two doses of maropitant (2 mg/kg and 4 mg/kg SC) for pain management in rabbits undergoing surgery [5]. The study found that rabbits receiving 4 mg/kg had significantly lower pain scores in the mid-time frame compared to controls. No adverse effects were observed [5]. - **Parrots:** A 2025 pharmacokinetic study in orange-winged Amazon parrots found that a 1 mg/kg dose of maropitant was well tolerated both IV and SC, with rapid absorption and a bioavailability of 85% [6]. The authors suggested that current dosing intervals may need adjustment for this species due to a short half-life [6]. - **Non-human Primates:** A 2025 study in cynomolgus macaques evaluated oral maropitant (2 mg/kg) for prevention of ketamine-induced emesis [7]. While maropitant reduced emesis from 58% in the control group to 50%, this reduction was not statistically significant. Ondansetron (1 mg/kg) showed a more pronounced (but also non-significant) reduction to 33% [7]. ## Dose Calculator: Practical Application This section provides a step-by-step guide to calculating the correct dose of maropitant for a dog or cat. Always confirm with a veterinarian before administering. ### Step 1: Confirm the Species and Indication - **Dog, acute vomiting:** 1 mg/kg SC or 2 mg/kg PO. - **Dog, motion sickness:** 8 mg/kg PO. - **Cat, vomiting:** 1 mg/kg SC (labeled). Oral dosing is off-label; a common dose is 1-2 mg/kg PO. ### Step 2: Obtain an Accurate Weight Use a scale. Do not guess. For small dogs and cats, even a 0.5 kg error can lead to a significant dose error. ### Step 3: Calculate the Dose Use the following formula: **Dose (mg) = Body Weight (kg) x Dose Rate (mg/kg)** **Example 1: Dog with acute vomiting** - Weight: 10 kg - Dose rate (SC): 1 mg/kg - Calculation: 10 kg x 1 mg/kg = 10 mg **Example 2: Dog with motion sickness** - Weight: 10 kg - Dose rate (PO): 8 mg/kg - Calculation: 10 kg x 8 mg/kg = 80 mg **Example 3: Cat with vomiting** - Weight: 4 kg - Dose rate (SC): 1 mg/kg - Calculation: 4 kg x 1 mg/kg = 4 mg ### Step 4: Determine the Volume of Liquid Formulation Cerenia injectable is typically available as a 10 mg/mL solution. To calculate the volume to draw up: **Volume (mL) = Dose (mg) / Concentration (mg/mL)** **Example 1 continued:** - Dose: 10 mg - Concentration: 10 mg/mL - Volume: 10 mg / 10 mg/mL = 1.0 mL **Example 3 continued:** - Dose: 4 mg - Concentration: 10 mg/mL - Volume: 4 mg / 10 mg/mL = 0.4 mL ### Step 5: Consider the Route and Administration - **Subcutaneous (SC):** Administer under the skin, typically over the shoulders or back. Be aware that injection can be painful [1][2]. - **Oral (PO):** Give tablets or liquid by mouth. For motion sickness, give the dose at least 1 to 2 hours before travel. ## Safety Profile and Adverse Effects Maropitant has a wide safety margin in dogs and cats, but it is not without side effects. ### Injection-Site Discomfort The most commonly reported adverse effect is pain at the injection site. In one study, 64.5% of dogs showed discomfort after SC injection of maropitant [1]. This is transient but can be pronounced. In another study on ECG changes, no adverse effects were witnessed apart from apparent pain on injection [2]. ### Gastrointestinal Motility Maropitant can decrease the rate of peristalsis in the stomach and jejunum [9]. This is a pharmacologic effect that could theoretically exacerbate conditions like constipation or ileus. If your pet is already showing signs of a gastrointestinal obstruction (e.g., vomiting and not passing stool), do not give maropitant without veterinary guidance. ### Cardiovascular Effects A 2025 study evaluated the ECG of healthy dogs after a 1 mg/kg SC dose of maropitant [2]. The study found a subtle prolongation of the corrected QT interval (QTc) that only reached significance with one correction formula (Van de Water). There were no tachyarrhythmias or bradyarrhythmias observed. A significant reduction in P wave amplitude was also observed [2]. While these changes were not clinically significant in healthy dogs, caution is warranted in patients with pre-existing cardiac disease. ### Sedation and Anesthetic Interactions Maropitant may have sedative properties. A 2026 study in cats evaluated the effect of maropitant on sedation and propofol requirements [13]. The study found that maropitant did not significantly alter sedation scores or propofol requirements compared to saline. However, other research suggests maropitant can reduce inhalant anesthetic requirements [11]. This means that if your pet is undergoing anesthesia, the anesthetist should be aware that maropitant is on board. ## Contraindications and Precautions - **Hypersensitivity:** Do not use in pets with a known allergy to maropitant. - **Gastrointestinal Obstruction:** Do not use maropitant if a foreign body or obstruction is suspected. The drug's effect on motility could mask clinical signs or worsen the condition [9]. - **Hepatic or Renal Disease:** Maropitant is metabolized in the liver. Use with caution in patients with severe hepatic dysfunction, and consider dose adjustments under veterinary guidance. - **Pregnancy and Lactation:** The safety of maropitant in pregnant or lactating animals has not been fully established. Use only when the benefits clearly outweigh the risks. - **Young Animals:** Maropitant is approved for use in puppies and kittens of a certain age (typically 8 weeks and older, but check local labeling). Safety in younger animals is not well established. ## Drug Interactions - **Other Antiemetics:** Maropitant can be combined with other antiemetics like ondansetron or metoclopramide, but this should be done by a veterinarian. A study in brachycephalic dogs undergoing spinal surgery found that adding metoclopramide to a protocol of maropitant and pantoprazole did not reduce the incidence of regurgitation or ptyalism [14]. - **Sedatives and Anesthetics:** As noted, maropitant may have additive effects with anesthetics. A study in cats found that maropitant, when used with dexmedetomidine, resulted in lower pain scores [4]. In dogs, it reduced desflurane requirements [11]. ## Special Considerations: Skin Testing and Allergies A 2026 study investigated whether maropitant influences intradermal test (IDT) reactivity in atopic dogs [8]. The study found that maropitant administration resulted in a small but statistically significant reduction in histamine-induced wheal size. This suggests that maropitant could potentially interfere with allergy testing. If your dog is scheduled for intradermal allergy testing, inform your veterinary dermatologist if maropitant has been administered recently [8]. ## Unsafe Home Remedies and Owner Warnings - **Never use human antiemetics:** Do not give your pet human medications like Dramamine (dimenhydrinate) or Zofran (ondansetron) without explicit veterinary instruction. Doses and safety profiles differ significantly between species. - **Do not use canine doses in cats:** Cats are more sensitive to certain drugs. Always use a feline-specific dose. - **Avoid in suspected toxin ingestion:** If your pet has eaten something toxic (e.g., chocolate, grapes, rat poison), do not give maropitant. The goal is to manage the toxin, not just stop the vomiting. Inducing vomiting or seeking immediate veterinary care is critical. - **Do not use for more than 24 hours without veterinary review:** If your pet continues to vomit after a single dose of maropitant, this is a red flag. Do not give a second dose; seek veterinary care. ## Prevention and Prognosis The prognosis for acute vomiting is generally excellent if the underlying cause is identified and treated. Maropitant is a supportive therapy that controls the clinical sign of vomiting, but it does not treat the underlying disease. - **For motion sickness:** Prevention is key. Give maropitant before travel, and pair it with behavioral modification to reduce anxiety. - **For gastroenteritis:** Maropitant can help break the vomiting cycle, allowing oral fluids and a bland diet to be introduced. However, if vomiting persists, more aggressive therapy (IV fluids, hospitalization) is needed. - **For chronic conditions:** In cases like inflammatory bowel disease or cyclic vomiting syndrome, maropitant may be part of a long-term management plan, but a definitive diagnosis is essential [10]. ## Limitations and When to Contact a Veterinarian This article provides a general overview and dose calculation guide. It cannot predict individual patient responses. Breed-level information is not a substitute for a physical examination. The following situations warrant immediate veterinary contact: - **Vomiting persists for more than 24 hours.** - **Your pet is lethargic, depressed, or unresponsive.** - **There is blood in the vomit or stool.** - **Your pet is trying to vomit but nothing is coming up (retching).** - **Your pet has a distended or painful abdomen.** - **You suspect your pet ingested a toxin or foreign body.** - **Your pet is a puppy, kitten, or a senior animal with other health conditions.** **Do not wait to see if things improve.** Vomiting can lead to rapid dehydration and electrolyte imbalances, especially in small breeds and cats. ## Frequently Asked Questions ### 1. What is the correct Cerenia dose for a dog with motion sickness? The labeled dose for motion sickness in dogs is 8 mg/kg orally once daily. It should be given at least 1 to 2 hours before travel to allow for adequate absorption. ### 2. Can I give my cat a dog dose of Cerenia? No, you should never give a cat a dose of any medication intended for a dog. The labeled dose for cats is 1 mg/kg subcutaneously for vomiting. Oral dosing in cats is off-label and should only be done under direct veterinary supervision. ### 3. How quickly does Cerenia start working? Cerenia is rapidly absorbed. In parrots, maximum plasma concentration was reached at 0.5 hours after subcutaneous administration [6]. In dogs and cats, clinical effects are typically seen within 1 to 2 hours after oral administration and faster after injection. ### 4. How long does Cerenia last? The duration of action for the labeled dose is 24 hours. However, studies in other species, such as parrots, show a short half-life, suggesting that dosing intervals may need to be shorter in those species [6]. ### 5. Is Cerenia safe for pregnant or nursing dogs and cats? The safety of maropitant in pregnant or lactating animals has not been fully established. It should only be used when the potential benefit justifies the potential risk to the fetus or nursing offspring. Always consult your veterinarian. ### 6. What are the common side effects of Cerenia? The most common side effect is pain at the injection site [1][2]. Other potential effects include changes in gastrointestinal motility (slowed peristalsis) [9] and subtle ECG changes [2]. Sedation is not commonly reported, but it may have additive effects with anesthetics [13][11]. ### 7. Can Cerenia be used for all types of vomiting? No. Cerenia is effective for vomiting mediated by substance P, which includes most cases of gastroenteritis, motion sickness, and drug-induced vomiting. It may not be effective for vomiting caused by certain toxins or metabolic conditions that stimulate other pathways [10]. ### 8. What should I do if my pet vomits after receiving Cerenia? If your pet vomits after receiving Cerenia, do not give another dose. Contact your veterinarian immediately. Persistent vomiting despite antiemetic therapy is a red flag for a more serious underlying condition, such as an obstruction or pancreatitis. ## Sources [1] [Effectiveness of dimenhydrinate and maropitant in preventing preoperative emesis and nausea in healthy dogs sedated with hydromorphone and dexmedetomidine: a randomized, blinded trial.](https://pubmed.ncbi.nlm.nih.gov/42208176/) [2] [Evaluation of Maropitant-Induced Changes in the Electrocardiogram of Healthy Dogs and Comparison of Three Methods for QT Interval Correction.](https://pubmed.ncbi.nlm.nih.gov/40522750/) [3] [The Effect of Maropitant, Ondansetron and Metoclopramide on Dexmedetomidine-Induced Vomiting in Cats.](https://pubmed.ncbi.nlm.nih.gov/39792081/) [4] [Evaluation of the antiemetic, sedative and analgesic effects of butorphanol and maropitant in combination with dexmedetomidine in cats undergoing ovariohysterectomy.](https://pubmed.ncbi.nlm.nih.gov/41405173/) [5] [Use of subcutaneous maropitant at two dosages for pain management in domestic rabbits (Oryctolagus cuniculus) undergoing elective ovariohysterectomy or orchiectomy.](https://pubmed.ncbi.nlm.nih.gov/38964540/) [6] [Maropitant citrate exhibits rapid absorption, short half-life, and fast clearance in orange-winged Amazon parrots (Amazona amazonica) following subcutaneous and intravenous administration.](https://pubmed.ncbi.nlm.nih.gov/40185128/) [7] [Incidence of Post-Sedation Emesis in Cynomolgus (Macaca fascicularis) and Rhesus (Macaca mulatta) Macaques, and Evaluation of Prophylactic Antiemetic Efficacy.](https://pubmed.ncbi.nlm.nih.gov/41302000/) [8] [Influence of Maropitant Citrate on Pollen and Control Intradermal Test Reactivity in Atopic Dogs: A Randomised, Controlled, Blinded Trial.](https://pubmed.ncbi.nlm.nih.gov/41449861/) [9] [Maropitant Citrate Administration Significantly Decreases the Rate of Peristalsis in the Stomach and Jejunum and Does Not Significantly Alter Intestinal Diameter or Intestinal Wall Thickness in Healthy Adult Dogs.](https://pubmed.ncbi.nlm.nih.gov/42083426/) [10] [Diagnosis and management of presumptive cyclic vomiting syndrome in a dog: first report in veterinary medicine.](https://pubmed.ncbi.nlm.nih.gov/41361810/) [11] [Cardiorespiratory Effects and Desflurane Requirement in Dogs Undergoing Ovariectomy after Administration Maropitant or Methadone.](https://pubmed.ncbi.nlm.nih.gov/37508165/) [12] [Post-treatment with maropitant reduces oxidative stress, endoplasmic reticulum stress and neuroinflammation on peripheral nerve injury in rats.](https://pubmed.ncbi.nlm.nih.gov/38507417/) [13] [The effect of maropitant on sedation, propofol requirements, and cardiovascular function at induction of anesthesia in healthy cats.](https://pubmed.ncbi.nlm.nih.gov/42006945/) [14] [Addition of a metoclopramide constant rate infusion to prevent ptyalism, regurgitation and vomiting in brachycephalic dogs undergoing spinal surgery.](https://pubmed.ncbi.nlm.nih.gov/39142985/)

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