Maropitant citrate is the active ingredient in Cerenia, a prescription antiemetic medication manufactured by Zoetis. It is the first and only FDA-approved veterinary-specific antiemetic and works by selectively blocking neurokinin-1 (NK1) receptors in the vomiting center of the brain (the chemoreceptor trigger zone and the nucleus tractus solitarius). NK1 receptors are activated by substance P, a key neurotransmitter involved in the vomiting reflex. By blocking this pathway, maropitant provides broad-spectrum antiemetic activity against vomiting triggered by multiple causes, including motion sickness, medications (chemotherapy), toxins, gastrointestinal disease, and vestibular disorders. Maropitant is available in both oral tablet and injectable formulations.
What Is Maropitant Used For?
Veterinarians prescribe maropitant for:
- Acute vomiting from various causes (gastritis, dietary indiscretion, pancreatitis, kidney disease, post-surgical nausea)
- Motion sickness prevention in dogs during car travel (FDA-approved for dogs 8 weeks and older)
- Chemotherapy-induced nausea and vomiting (CINV)
- Perioperative nausea prevention
- Visceral pain (maropitant has emerging evidence for visceral analgesic properties via NK1 blockade)
Maropitant controls vomiting but does not address the underlying cause. Your veterinarian will investigate and treat the primary condition causing nausea or vomiting.
Dosage
Dosing depends on the indication and route of administration. Your veterinarian will determine the appropriate dose.
Oral Tablets (Prevention and Treatment of Vomiting)
| Dog’s Weight | Minimum Dose (2 mg/kg) | Indication |
|---|---|---|
| 5 lbs (2.3 kg) | 4.6 mg once daily | Acute vomiting |
| 10 lbs (4.5 kg) | 9 mg once daily | Acute vomiting |
| 25 lbs (11 kg) | 22 mg once daily | Acute vomiting |
| 50 lbs (23 kg) | 46 mg once daily | Acute vomiting |
| 75 lbs (34 kg) | 68 mg once daily | Acute vomiting |
- Acute vomiting: 2 mg/kg orally once daily for up to 5 consecutive days.
- Motion sickness: 8 mg/kg orally once daily, given at least 2 hours before travel. FDA-approved for dogs 8 weeks and older for this indication.
Cerenia tablets are available in 16 mg, 24 mg, 60 mg, and 160 mg strengths. Give with a small amount of food to reduce the chance of vomiting the tablet.
Injectable (Administered by Veterinarian)
- 1 mg/kg subcutaneously once daily for up to 5 days for acute vomiting in dogs 16 weeks and older.
Side Effects
| Common Side Effects | Serious Side Effects (Contact Your Vet) |
|---|---|
| Excessive drooling (oral dosing) | Allergic reaction (swelling, hives, difficulty breathing) |
| Mild drowsiness | Persistent vomiting despite treatment |
| Decreased appetite | Severe lethargy or depression |
| Pain at injection site (injectable) | Blood in vomit or stool |
| Mild diarrhea |
Maropitant is generally well tolerated. The injectable formulation may cause transient pain or stinging at the injection site; refrigerating the solution before injection can minimize discomfort. If vomiting persists despite maropitant treatment, further veterinary evaluation is needed.
Drug Interactions
- Highly protein-bound drugs (NSAIDs, cardiac medications): Maropitant is highly protein-bound and may interact with other protein-bound drugs; use with veterinary oversight.
- Calcium channel blockers: Use with caution (potential for cardiac interactions).
- CYP3A4 substrates and inhibitors (ketoconazole, erythromycin): May affect maropitant metabolism.
Maropitant is commonly used alongside other medications (antibiotics, gastroprotectants, fluid therapy) in the management of vomiting. Always inform your veterinarian of all medications your dog is taking.
Contraindications
Maropitant should not be used in:
- Dogs with known hypersensitivity to maropitant citrate
- Puppies under 8 weeks of age (oral, for motion sickness) or under 16 weeks of age (injectable, for acute vomiting)
Use with caution in dogs with hepatic dysfunction, as maropitant is extensively metabolized by the liver. Your veterinarian will assess liver function when appropriate.
Storage
- Tablets: Store at controlled room temperature, 68-77 degrees F (20-25 degrees C). Keep in original packaging.
- Injectable solution: Store at controlled room temperature. Do not refrigerate the vial for long-term storage (refrigerating individual doses before injection to reduce pain at the injection site is acceptable).
- Keep out of reach of children and pets.
Frequently Asked Questions
How quickly does maropitant work? The injectable form works within approximately 1 hour. Oral tablets take approximately 1 to 2 hours to reach effective blood levels. For motion sickness prevention, give the tablet at least 2 hours before travel.
Can maropitant be used long-term? Maropitant is FDA-approved for up to 5 consecutive days of use. Longer-term use may be prescribed off-label by your veterinarian for chronic conditions such as ongoing chemotherapy-induced nausea. Consult your veterinarian about appropriate duration.
Is maropitant the same as Cerenia? Yes. Maropitant citrate is the generic (active ingredient) name; Cerenia is the brand name manufactured by Zoetis. No generic version is currently available.
Can maropitant be used in cats? Cerenia is also FDA-approved for cats for the prevention of vomiting (injectable form). However, this page focuses on canine use. Consult your veterinarian for feline dosing and indications.
Does maropitant help with diarrhea? Maropitant specifically targets the vomiting reflex and does not directly treat diarrhea. However, by controlling nausea, it may improve a dog’s appetite and comfort during GI illness. Your veterinarian will address diarrhea separately.
This content is for informational purposes only and is not a substitute for professional veterinary advice. Always consult your veterinarian before starting, changing, or stopping any medication for your dog.