VetMedAcute vomiting: maropitant vs metoclopramide — LIKELY
In dogs with acute vomiting of mixed cause, does maropitant stop vomiting more reliably than metoclopramide (bolus or CRI)?
Shelf #168 · gate-verified and approved by the developer
LIKELY: In the target population — dogs with ongoing emesis from a wide range of causes — a two-phase multicentre randomised trial found maropitant clearly ahead of label-dose metoclopramide given two or three times daily: 97% of maropitant dogs versus 71% of metoclopramide dogs did not vomit after treatment in phase I (P<0.01), and in phase II emesis was lower with maropitant during the first 24 hours (P<0.0001) and for each day thereafter. The direction is consistent across designs: maropitant halved continued vomiting versus placebo in a 278-dog randomised clinical trial (21.8% vs 50% still vomiting); against morphine-induced emesis, incidence was 0% with maropitant versus 38% with metoclopramide and 71% with saline; in a blinded cisplatin cross-over, no maropitant-treated dog vomited while metoclopramide had no effect on vomiting or nausea; and in emetogen-challenge studies maropitant covered both central and peripheral pathways, where metoclopramide covered only the central one. Two limits keep this at LIKELY, not higher: no carded study compares maropitant against a metoclopramide constant rate infusion (every carded metoclopramide regimen is a bolus or divided daily dose), and one small randomised parvovirus study (8 dogs per group) found the two drugs equally effective — so the advantage is established for the bolus-era comparisons and most causes tested, not for every regimen or every cause. Drafted Nov 10, 2026 (VetMed build, topic #168); all figures from abstracts fetched and verified at drafting.
de la Puente-Redondo 2007: 97% of maropitant dogs vs 71% of metoclopramide dogs did not vomit after treatment, in a two-phase multicentre randomised trial in ongoing emesis of various causes
Multicenter randomized controlled trial, two-phase (record's publication types and abstract wording; blinding not stated)
Who: Dogs: dogs with ongoing emesis caused by a wide range of underlying clinical aetiologies, presented at veterinary clinics in France, Italy, Slovakia and the UK. Phase I: maropitant 32 dogs, metoclopramide 34 dogs (randomised 1:1). Phase II: maropitant 77 dogs, metoclopramide 40 dogs (randomised 2:1). Maropitant was given subcutaneously at 1 mg/kg/day for up to five days; metoclopramide was given as licensed on the product labels at 0.5 to 1 mg/kg/day subcutaneously or orally, the daily dose divided over two to three administrations per day, for up to three to five days.
Result: In phase I, 97 per cent of dogs treated with maropitant and 71 per cent of dogs treated with metoclopramide did not vomit after treatment (P<0.01). The mean number of emetic events after maropitant treatment was significantly reduced compared with that after metoclopramide treatment (P=0.01). In phase II, the occurrence of emesis was lower for maropitant during the first 24 hours (P<0.0001) and for each day thereafter. The authors conclude a single daily dose of maropitant was more effective than metoclopramide administered two or three times daily in the treatment of emesis caused by various aetiologies in dogs.
Watch out: This is the genuine head-to-head anchor for the shelf question, from the maropitant licensure-era programme. Two cautions: the record states randomisation (1:1 in phase I, 2:1 in phase II) but does not state blinding, so none is claimed; and the metoclopramide comparator is the licensed divided-dose regimen (two to three administrations per day), not a constant rate infusion — no CRI comparison is made anywhere on this shelf. Phase II reports P values without the underlying percentages in the abstract, so only the phase I percentages are carded as figures.
de la Puente-Redondo VA, Siedek EM, Benchaoui HA, Tilt N, Rowan TG, Clemence RG. The anti-emetic efficacy of maropitant (Cerenia) in the treatment of ongoing emesis caused by a wide range of underlying clinical aetiologies in canine patients in Europe. J Small Anim Pract. 2007;48(2):93-8. PMID: 17286662. Registry ID: none in the record. MeSH: Animals · Antiemetics/administration & dosage,therapeutic use · Dog Diseases/drug therapy,etiology,pathology · Dogs · Europe · Female · Male · Quinuclidines/administration & dosage,therapeutic use · Treatment Outcome · Vomiting/drug therapy,veterinary
Ramsey 2008: in a 278-dog randomised clinical trial, 21.8% of maropitant dogs vs 50% of placebo dogs continued to vomit
Randomized clinical trial (record's own title and abstract wording; multicentre; blinding not stated)
Who: Dogs: 278 dogs enrolled from 29 veterinary hospitals with acute vomiting due to various etiologies (252 evaluable for efficacy, 275 for safety), allocated by a randomized block design (three maropitant- and one placebo-treated dog per block). Initial treatment was maropitant 1 mg/kg or an equivalent volume of saline (placebo) subcutaneously, followed on subsequent 1 to 4 days by maropitant or placebo subcutaneously or orally (tablets delivering a minimum 2 mg/kg) at approximately 24-hour intervals as needed; dogs were observed twice daily for vomiting.
Result: Emesis was significantly (P ≤ 0.0012) reduced in maropitant-treated dogs: 50% (32/64) of placebo-treated dogs continued to vomit compared to only 21.8% (41/188) of maropitant-treated dogs. Post-treatment clinical signs were consistent with clinical diagnoses and judged not to be treatment related. The authors conclude maropitant was safe and effective in reducing emesis due to various etiologies in dogs.
Watch out: Context card, not a head-to-head: the comparator is placebo, so this card establishes maropitant's absolute efficacy in the target population (acute vomiting, various etiologies) rather than its advantage over metoclopramide. The 3:1 allocation explains the unequal group sizes (188 vs 64 evaluable). Blinding is not stated in the record and is not claimed.
Ramsey DS, Kincaid K, Watkins JA, Boucher JF, Conder GA, Eagleson JS, Clemence RG. Safety and efficacy of injectable and oral maropitant, a selective neurokinin 1 receptor antagonist, in a randomized clinical trial for treatment of vomiting in dogs. J Vet Pharmacol Ther. 2008;31(6):538-43. PMID: 19000277. Registry ID: none in the record. MeSH: Administration, Oral · Animals · Dogs · Drug-Related Side Effects and Adverse Reactions · Female · Injections, Subcutaneous · Male · Neurokinin-1 Receptor Antagonists · Quinuclidines/administration & dosage,pharmacology,therapeutic use · Vomiting/drug therapy,etiology,veterinary
Sedlacek 2008: maropitant matched metoclopramide against central emetogen challenge and beat it against peripheral challenge, in two randomised placebo-controlled cross-over studies
Comparative study: two randomized, placebo-controlled crossover studies (record's own wording)
Who: Dogs: in each of two studies, ten male and ten female beagles in an experimental setting, treated in a five-treatment, five-period crossover design with 0.9% saline (0.1 mL/kg), maropitant (1 mg/kg), metoclopramide (0.5 mg/kg) or chlorpromazine (0.5 mg/kg), all subcutaneously, or ondansetron (0.5 mg/kg) intravenously; one hour post-treatment dogs were challenged with apomorphine 0.1 mg/kg intravenously (Study 1, centrally acting) or syrup of ipecac 0.5 mL/kg orally (Study 2, peripherally acting), and observed for emesis for 30 minutes or 1 hour respectively.
Result: Against apomorphine, efficacy of maropitant in preventing emesis was not different (P > 0.05) from metoclopramide or chlorpromazine but was superior (P < 0.0001) to ondansetron. Against syrup of ipecac, maropitant was not different (P > 0.05) from ondansetron but was superior (P ≤ 0.0102) to metoclopramide or chlorpromazine. Maropitant was effective (P < 0.0001 relative to control) in preventing vomiting from either central or peripheral stimulation, whereas the other drugs prevented vomiting from central (metoclopramide and chlorpromazine; P < 0.0001) or peripheral (ondansetron; P < 0.0001) stimulation but not both.
Watch out: Experimental emetogen-challenge studies in healthy beagles — prevention of induced emesis, not treatment of clinical vomiting — and the abstract reports P values without per-treatment emesis percentages, so none are carded. The record's MeSH includes a 'Humans' term; it is copied exactly as printed. Carded for the mechanistic pattern (maropitant active at both emetic pathways, metoclopramide only centrally), which is consistent with the clinical head-to-head result.
Sedlacek HS, Ramsey DS, Boucher JF, Eagleson JS, Conder GA, Clemence RG. Comparative efficacy of maropitant and selected drugs in preventing emesis induced by centrally or peripherally acting emetogens in dogs. J Vet Pharmacol Ther. 2008;31(6):533-7. PMID: 19000276. Registry ID: none in the record. MeSH: Animals · Apomorphine · Cross-Over Studies · Dogs · Emetics/adverse effects · Humans · Ipecac/adverse effects · Male · Neurokinin-1 Receptor Antagonists · Quinuclidines/pharmacology,therapeutic use · Vomiting/chemically induced,prevention & control,veterinary
Lorenzutti 2017: morphine-induced emesis occurred in 0% of maropitant dogs vs 38% with metoclopramide and 71% with saline
Comparative clinical study (record's publication type: Randomized Controlled Trial; abstract does not itself use the word randomised)
Who: Dogs: 63 dogs given subcutaneous maropitant [1 mg/kg body weight (BW)], metoclopramide (0.5 mg/kg BW) or normal saline (0.1 mL/kg BW) 45 minutes before morphine (0.5 mg/kg BW) and acepromazine (0.05 mg/kg BW) as preanaesthetic medication, and observed for signs of nausea (ptyalism, lip licking, increased swallowing) and vomiting for 30 minutes after morphine/acepromazine.
Result: The incidence of emesis was 0% for maropitant, 38% for metoclopramide, and 71% for saline (P < 0.001). The incidence of signs of nausea was not different between groups. Discomfort due to injection was higher after maropitant (48%) than after metoclopramide (9.8%) and saline (4.8%) (P < 0.001).
Watch out: A prevention study in a single induced cause (opioid premedication), not treatment of spontaneous acute vomiting; group sizes per arm are not stated in the abstract, so only the percentages are carded. Note the trade-off the record does state: maropitant injection caused more discomfort (48%) than metoclopramide (9.8%). Nausea signs did not differ between groups — the advantage shown is on emesis, not on nausea.
Lorenzutti AM, Martín-Flores M, Litterio NJ, Himelfarb MA, Invaldi SH, Zarazaga MP. A comparison between maropitant and metoclopramide for the prevention of morphine-induced nausea and vomiting in dogs. Can Vet J. 2017;58(1):35-38. PMID: 28042152. Registry ID: none in the record. MeSH: Analgesics, Opioid/adverse effects · Animals · Antiemetics/therapeutic use · Dog Diseases/chemically induced · Dogs · Female · Hysterectomy/veterinary · Male · Metoclopramide/therapeutic use · Morphine/adverse effects · Nausea/chemically induced,veterinary · Orchiectomy/veterinary · Ovariectomy/veterinary · Quinuclidines/therapeutic use · Vomiting/chemically induced,veterinary
Kenward 2017: in a blinded cisplatin cross-over, no dog vomited on maropitant or ondansetron, while metoclopramide had no effect on vomiting or nausea
Blinded crossover study (record's own wording; experimental cisplatin model)
Who: Dogs: eight healthy beagle dogs of both genders in an experimental setting, in a four-period cross-over blinded study; each received cisplatin 18 mg/m2 intravenously followed 45 minutes later by a 15-minute infusion of placebo (saline), ondansetron (0.5 mg/kg), maropitant (1 mg/kg) or metoclopramide (0.5 mg/kg), with vomits and nausea-associated behaviours scored every 15 minutes for 8 hours.
Result: The placebo-treated group vomited an average of 7 times (range 2-13). None of the dogs in either the ondansetron or maropitant treated groups vomited during the observation period. Metoclopramide had no effect on either vomiting or nausea. Ondansetron and maropitant reduced the overall area under the curve of nausea behaviour score by 90% and 25%, respectively; the placebo group's nausea behaviour score peaked at 58.5 ± 4.6 mm at t4.75h. Terminal half-lives (harmonic mean ± pseudo SD) were 1.21 ± 0.51 h (ondansetron), 5.62 ± 0.77 h (maropitant) and 0.87 ± 0.17 h (metoclopramide).
Watch out: Eight healthy beagles and a chemotherapy-emetogen model, not clinical patients — and on the nausea endpoint (as opposed to vomiting) ondansetron outperformed maropitant (90% vs 25% reduction in nausea behaviour score area under the curve). Carded because it is the shelf's blinded head-to-head and shows a clean vomiting result (zero vomits on maropitant; no effect from single-dose metoclopramide), not because its setting matches the shelf question.
Kenward H, Elliott J, Lee T, Pelligand L. Anti-nausea effects and pharmacokinetics of ondansetron, maropitant and metoclopramide in a low-dose cisplatin model of nausea and vomiting in the dog: a blinded crossover study. BMC Vet Res. 2017;13(1):244. PMID: 28814338. Registry ID: none in the record. MeSH: Animals · Antiemetics/pharmacology,therapeutic use · Arginine Vasopressin/analysis · Cisplatin/adverse effects · Cross-Over Studies · Dogs · Female · Hydrocortisone/analysis · Male · Metoclopramide/pharmacology,therapeutic use · Nausea/chemically induced,prevention & control,veterinary · Ondansetron/pharmacology,therapeutic use · Quinuclidines/pharmacology,therapeutic use · Vomiting/chemically induced,prevention & control,veterinary
Yalcin 2017: in parvoviral enteritis, maropitant, metoclopramide and ondansetron were equally effective against vomiting — the shelf's contrary randomised result
Randomized, prospective clinical study (record's own wording; publication types include Randomized Controlled Trial)
Who: Dogs: parvovirus quick ELISA test-positive dogs between 4 and 12 months of age with parvoviral enteritis, in a randomized, prospective clinical study; each of the metoclopramide, ondansetron, maropitant and control groups had 8 dogs. Metoclopramide and ondansetron were given at 0.5 mg/kg three times a day intravenously, and maropitant at 1 mg/kg once a day subcutaneously; all dogs were treated and monitored for five days and treatments continued until all animals healed.
Result: Metoclopramide, ondansetron and maropitant decreased the severity of vomiting from the first day and the vomiting numbers from the third day in parvoviral enteritis treatment. The authors report that maropitant can be used successfully such as metoclopramide and ondansetron, and that metoclopramide, ondansetron and maropitant were equally effective in reducing the frequency and severity of vomiting. No per-group vomiting figures are given in the abstract, so none are carded.
Watch out: The contrary card, kept deliberately: with only 8 dogs per group it had little power to detect a difference, and it addresses one cause (parvoviral enteritis) with metoclopramide given as intravenous boluses three times daily, not a CRI. It prevents the shelf from claiming maropitant superiority for every cause, but it does not outweigh the much larger multicentre trial in mixed-cause emesis.
Yalcin E, Keser GO. Comparative efficacy of metoclopramide, ondansetron and maropitant in preventing parvoviral enteritis-induced emesis in dogs. J Vet Pharmacol Ther. 2017;40(6):599-603. PMID: 28198032. Registry ID: none in the record. MeSH: Animals · Antiemetics/therapeutic use · Dog Diseases/etiology,prevention & control · Dogs · Female · Male · Metoclopramide/therapeutic use · Ondansetron/therapeutic use · Parvoviridae Infections/complications,veterinary · Parvovirus, Canine · Quinuclidines/therapeutic use · Treatment Outcome · Vomiting/chemically induced,prevention & control
Synthesis: yes — for acute vomiting of mixed cause, maropitant stops vomiting more reliably than bolus/divided-dose metoclopramide; the CRI comparison has never been carded because no such head-to-head record was found
Synthesis
Who: Synthesis of the cards above: de la Puente-Redondo 2007 (183 dogs across two phases, multicentre randomised trial in ongoing emesis of various aetiologies), Ramsey 2008 (278 dogs, randomised placebo-controlled clinical trial), Sedlacek 2008 (two randomised placebo-controlled emetogen cross-over studies, 20 beagles each), Lorenzutti 2017 (63 dogs, morphine-induced emesis), Kenward 2017 (8 healthy beagles, blinded cisplatin cross-over) and Yalcin 2017 (32 parvovirus dogs, randomised clinical study).
Result: Across the clinical, induced-emesis and experimental records the pattern is one-directional for vomiting: maropitant beat metoclopramide in the large mixed-cause clinical trial (97% vs 71% vomit-free after treatment, phase I), in morphine-induced emesis (0% vs 38% incidence), and in the blinded cisplatin model (zero vomits versus no metoclopramide effect), and it was the only drug active against both central and peripheral emetogen challenge. Against placebo in acute vomiting of various etiologies, maropitant cut continued vomiting from 50% to 21.8% (an absolute difference of about 28 percentage points). The single contrary result is a very small parvovirus trial reporting equal efficacy. No carded record tests a metoclopramide constant rate infusion against maropitant, and maropitant's advantage is on vomiting — nausea signs did not differ in Lorenzutti 2017, and ondansetron beat maropitant on nausea scores in Kenward 2017.
Watch out: Most head-to-head evidence is industry-era licensure research in induced emesis or with label bolus dosing; spontaneous-disease trials are thinner, and hospitalised dogs on metoclopramide CRIs — a common real-world regimen — are unrepresented in the carded records. Antiemetic success also does not treat the underlying cause of vomiting, which none of these records addresses.
Synthesis of de la Puente-Redondo VA et al. PMID: 17286662; Ramsey DS et al. PMID: 19000277; Sedlacek HS et al. PMID: 19000276; Lorenzutti AM et al. PMID: 28042152; Kenward H et al. PMID: 28814338; Yalcin E et al. PMID: 28198032. Registry IDs as on the individual cards.
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