Your dog has a bottle of Cerenia on the counter and you want to check the tablets against their weight. You find a dosage chart in seconds. What you do not find is a warning that there are two charts, that they differ fourfold, and that picking the wrong one is easy because both are correct.
Cerenia (maropitant citrate) does one job — it stops vomiting — at two separate doses depending on the reason. A dog treated for acute vomiting gets one rate; a dog dosed before a car journey gets four times it. The two also carry different limits on consecutive days, different minimum ages, and different instructions about food.
Below: both charts as the FDA label publishes them; why it calls each figure a minimum dose, and what that means for a dog whose weight is not on the chart; why the travel dose is capped at two days; how long before a car ride to give it; and what to do when a dose is missed or comes back up.
Key takeaways
- Two doses, four times apart. The FDA label gives a "minimum dose of 2 mg/kg (0.9 mg/lb)" for acute vomiting and "8 mg/kg (3.6 mg/lb)" for motion sickness.¹
- Both charts list only the weights that land exactly on the dose. All 19 rows across the label's two tables resolve to precisely 2.000 or 8.000 mg/kg. The label's instruction for every other weight is to dispense the tablets that "most closely result in" that dose.¹
- The travel dose stacks, which is why it is capped at two days. On repeat dosing the label records an accumulation ratio of 4.81 at 8 mg/kg against 2.46 at 2 mg/kg, with half-life rising from 7.69 to 25.4 hours.¹
- Timing is measurable, and earlier is not better. A two-trial study in 189 dogs cut vomiting by 86.1% dosed about 2 hours before travel, but 76.5% dosed about 10 hours before.⁵
What is the Cerenia dosage for dogs by weight?
It depends which of two jobs the tablet is doing. For preventing acute vomiting, the FDA-approved label directs "a minimum dose of 2 mg/kg (0.9 mg/lb)" once daily. For motion sickness, the same label directs "a minimum dose of 8 mg/kg (3.6 mg/lb)" once daily in dogs 4 months and older.¹
Maropitant is not a sedative and not an antihistamine. Merck describes it as "a neurokinin-1 (NK-1) receptor antagonist approved to treat and prevent emesis in dogs and cats," blocking substance P, "a regulatory peptide that binds to the NK-1 receptors and induces emesis."² Acting at that final common step is why Merck calls it "the preferred drug to treat motion sickness in dogs."³ It is prescription-only: the label restricts it "to use by or on the order of a licensed veterinarian."¹
Tablets come in four strengths: 16, 24, 60 and 160 mg. Here is the acute-vomiting chart as the label publishes it. These are the label's own example weights.¹
| Dog weight (lb) | Dog weight (kg) | Tablets — acute vomiting | Total mg |
|---|---|---|---|
| 8 | 4 | ½ × 16 mg | 8 mg |
| 15 | 8 | 1 × 16 mg | 16 mg |
| 25 | 12 | 1 × 24 mg | 24 mg |
| 50 | 24 | 2 × 24 mg | 48 mg |
| 65 | 30 | 1 × 60 mg | 60 mg |
| 130 | 60 | 2 × 60 mg | 120 mg |
And the motion-sickness chart, which most dosage-chart pages leave out entirely.¹ Note how much finer the weight steps are, and how fast the milligrams climb.
| Dog weight (lb) | Dog weight (kg) | Tablets — motion sickness | Total mg |
|---|---|---|---|
| 2 | 1 | ½ × 16 mg | 8 mg |
| 3 | 1.5 | ½ × 24 mg | 12 mg |
| 4 | 2 | 1 × 16 mg | 16 mg |
| 6 | 3 | 1 × 24 mg | 24 mg |
| 8 | 4 | 2 × 16 mg | 32 mg |
| 13 | 6 | 2 × 24 mg | 48 mg |
| 16 | 7.5 | 1 × 60 mg | 60 mg |
| 22 | 10 | ½ × 160 mg | 80 mg |
| 33 | 15 | 2 × 60 mg | 120 mg |
| 44 | 20 | 1 × 160 mg | 160 mg |
| 66 | 30 | 1½ × 160 mg | 240 mg |
| 88 | 40 | 2 × 160 mg | 320 mg |
| 132 | 60 | 3 × 160 mg | 480 mg |
Put one dog through both charts and the gap stops being abstract. At 65 lb — about 30 kg, a weight that appears in both tables — it is one 60 mg tablet to settle vomiting, or 240 mg before a car ride.¹ Four times the milligrams, same bottle, same afternoon.
Why does the label say "minimum dose" and not just the dose?
Because the figure is a floor, and tablets do not divide finely enough to hit it exactly. Work the tables backwards and the pattern is striking: 8 mg over 4 kg, 16 over 8, 24 over 12, 48 over 24, 60 over 30, 120 over 60 — every row lands on precisely 2.000 mg/kg. All thirteen motion-sickness rows land on 8.000. Nineteen rows, no rounding error anywhere.¹
That is not a coincidence. Those are the weights at which whole and half tablets land exactly on the dose — examples, not categories. The label's actual instruction is to "dispense whole or half tablets in strength(s) that most closely result in a 2 mg/kg dose."¹
Your dog is probably not one of those nineteen weights. With four strengths and halves, the closest achievable dose for an in-between weight sits a little above or below the nominal rate — and the word "minimum" tells your vet which way to err. That is a dispensing judgement, made by a veterinarian rather than read off a chart.
Small dogs feel this most. Half a 16 mg tablet is 8 mg, the smallest unit available. For a 4 kg dog that is exactly 2 mg/kg; for a 2 kg dog the same half tablet is 4 mg/kg — twice the nominal rate, still within the label.¹
Two consequences follow. A dose that matches no chart row is probably not an error — the chart does not contain most weights. And never add to or subtract from what was dispensed because the arithmetic looks off to you: at these strengths the nearest achievable dose is often the only one available. If the bottle worries you, call your vet, not the chart.
Why is Cerenia capped at two days for travel but not for vomiting?
Because the higher dose accumulates, and the label's own data shows by how much. For acute vomiting the label allows up to 5 consecutive days in dogs 2 to 7 months, and once daily "until resolution of acute vomiting" in dogs 7 months and older. For motion sickness, "up to 2 consecutive days" — at any age.¹
That looks arbitrary until you read the label's single-dose and repeat-dose figures side by side.¹
| Pharmacokinetic measure | 2 mg/kg (vomiting dose) | 8 mg/kg (travel dose) |
|---|---|---|
| Time to peak level, single dose | 2.0 hours | 1.5 hours |
| Peak concentration, single dose | 154 ng/mL | 588 ng/mL |
| 24-hour exposure, single dose | 1,440 ng·hr/mL | 6,730 ng·hr/mL |
| Half-life on repeat dosing | 7.69 hours | 25.4 hours |
| Accumulation ratio on repeat dosing | 2.46 | 4.81 |
Read the bottom two rows together. At the vomiting dose the drug clears in well under a day, so each tablet starts from a low baseline. At the travel dose half-life stretches past a full day — the next tablet lands before the last has gone, and exposure builds nearly fivefold rather than doubling.
That is what makes the two-day rule make sense. It is the point where a drug with a 25-hour half-life given every 24 hours stops being a once-daily drug.¹ If your journey runs longer, ask your vet before you leave rather than deciding at a service station.
How long before a car ride should you give Cerenia?
Two hours — not "the night before." Two randomized crossover trials enrolled 189 dogs with a history of motion sickness across 26 veterinary clinics in 12 US states. Dosed about 2 hours before a 60-minute car ride, maropitant cut vomiting against placebo by 86.1%; dosed about 10 hours before, by 76.5%.⁵
Both results are good. But the gap runs opposite to instinct, which is to dose early so the drug has "time to work." Giving the tablet with last night's dinner for a 7 AM departure puts you in the weaker arm.⁵
The label: "Administer CERENIA Tablets a minimum of two hours prior to travel with a small amount of food to mitigate vomiting associated with administration of the dose on an empty stomach; however, refrain from feeding a full meal prior to travel."¹ Merck adds: "Dogs should not be fed for 1 hour before maropitant is administered."²
VCA turns that into a clock: "feed your pet a small meal 3 hours before traveling. Then, 1 hour later (2 hours before travel), administer maropitant citrate."⁴ Small meal at three hours out, tablet at two, nothing more until you arrive. Getting it swallowed is its own battle — our guide to giving a dog or cat a pill without the fight covers that.
One caveat: Cerenia stops the vomiting, not the fear. Merck notes that "fear of the vehicle can also become a contributory factor," with dogs showing signs "even in stationary vehicles," and that it "can be overcome by conditioning the animal to travel."³ A dog who panics needs more than an antiemetic. Merck lists trazodone at 5–7.5 mg/kg 90 minutes beforehand — our guide to trazodone dosing covers it.
How long does Cerenia take to work, and how long does it last?
One to two hours to take effect, and roughly 24 hours of cover. VCA: "This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow," with effects ending "within 24 hours, although effects can be longer in pets with liver or kidney disease."⁴
The label agrees: peak blood levels arrive 2.0 hours after a 2 mg/kg dose and 1.5 hours after an 8 mg/kg dose.¹ That is the arithmetic behind the two-hour rule. The liver and kidney caveat matters for older dogs: a drug that normally clears inside a day may not, and a once-daily schedule assumes it does.
Which Cerenia side effects are expected, and which need a vet?
Drooling is the commonest, and most reported reactions sit close to placebo. In the label's US motion-sickness field study, 208 dogs received Cerenia and 195 placebo. Hypersalivation occurred in 12.5% against 9.7%; vomiting in 5.3% against 0%; muscle tremors in 1.0% against 0.5%; sedation or depression in 1.0% against 1.5%; retching in 0.5% against 1.5%.¹
Only hypersalivation and vomiting sit meaningfully above placebo, and sedation was reported slightly less often on Cerenia — useful if you have been told the drug will dope your dog. It is not a sedative.
VCA lists rarer reactions as decreased appetite, diarrhea, allergic reactions and uncoordinated walking, with drooling and vomiting commoner at the higher dose.⁴ The label's post-approval reports add ataxia, convulsion, weight loss, hyperactivity and panting.¹ Treat a seizure, collapse, facial swelling or hives as an emergency.
Some situations make Cerenia the wrong drug at any dose. VCA advises avoiding it in pets that "have ingested toxins," have a gastrointestinal obstruction, or are under 8 weeks old.⁴ Suppressing vomiting in a dog who swallowed something harmful, or whose gut is blocked, removes a protective reflex. "My dog ate something and is being sick" is a phone call, not a chart lookup.
What if you miss a dose, or your dog vomits the tablet back up?
Give a missed dose when you remember, then restart the clock — do not double up. VCA: "If you miss a dose, give it as soon as you remember, and then wait the recommended amount of time between doses."⁴ With a once-daily drug the next dose simply moves.
A vomited tablet is ambiguous, and no chart can tell you how much was absorbed. Peak levels arrive at 1.5 to 2 hours, so a tablet returned within minutes delivered little; one returned at ninety minutes delivered a good deal.¹ Re-dosing on a guess risks stacking a drug that accumulates. Note when it went in, when it came back, and whether you saw it — then ask.
This is where households lose the thread. Two doses that look nothing alike, a day-count that matters, a tablet given while packing a car. One person doses before loading the dog; another, finding no note, doses again. What to have written down:
- Which dose this was — travel or vomiting. "One tablet" means nothing when strengths run 16 to 160 mg.¹
- The exact time it went in — the two-hour window is the whole mechanism.⁵
- Which day of the course this is — day two is the last permitted travel day.¹
- Whether it stayed down, and if not, how long after.
- Drooling, tremor or wobbliness, with the time it started.⁴
A shared record also prevents the commonest failure with any once-daily medication: two people dosing the same dog within an hour. Our guide to keeping a household dosing rota straight covers the habits that stop it.
Can puppies and cats take Cerenia?
Puppies yes, from 8 weeks for vomiting and 16 weeks for travel; cats are a separate case. Merck gives tablets for dogs 8 weeks and older at 2 mg/kg every 24 hours for acute vomiting, and for dogs 16 weeks and older at 8 mg/kg for motion sickness.² The label matches, capping the vomiting course at 5 consecutive days in dogs aged 2 to 7 months.¹
Below 8 weeks the drug is not appropriate at all. The label records that "in puppies younger than 11 weeks of age, histological evidence of bone marrow hypocellularity was observed" — which is why that bound is a boundary, not a suggestion.¹
For cats, the approved route is the injection. Merck gives injectable maropitant for cats 16 weeks and older at 1 mg/kg every 24 hours; VCA notes that using the tablets in cats for nausea is off label.²⁴ Off label is lawful and routine, but it is a decision your vet makes with your cat in front of them. Never dose a cat from a dog's chart.
Cerenia is also only one option. For motion sickness Merck lists diphenhydramine at 2–4 mg/kg by mouth every 8 hours — the active ingredient in Benadryl, sold without a prescription and far weaker at this job.³ Our guide to how much Benadryl you can give a dog sets out that dosing.
What do the other Cerenia dosage charts leave out?
Checked against the live pages rather than their snippets, the gaps are consistent. VetLens gives both mg/kg rates and both day caps but no weight chart. AKC gives only mg/lb figures — 0.9 and 3.6 — with no day limits and no chart. petdosagechart.com publishes a chart but collapses both indications into one "2 mg per kg" standard across a "1–8 mg/kg" range, so a reader looking up a travel dose gets the vomiting dose.⁶ None of the three uses the label's word "minimum", separates dogs 2 to 7 months from dogs 7 months and older, or mentions accumulation.
Summaries drop things. Read your own prescription label, and treat any chart as a cross-check rather than an instruction.
Veterinary medical disclaimer: SteadyTails is a logging and coordination tool, not a substitute for veterinary care. Nothing on this page is a diagnosis, a prescription or a dosing instruction. Cerenia is prescription-only, and every figure quoted or derived here is a dose rate recorded in the FDA-approved label or a veterinary reference, not an amount to give your dog — the only dose that governs your dog is the one on your prescription label. Never start, stop, repeat or increase a dose on your own judgement, never re-dose after a vomited tablet without asking, and never give Cerenia to a dog who may have swallowed something toxic or whose gut may be blocked — suppressing vomiting there removes a protective reflex. If your dog seizures, collapses, develops facial swelling or hives, keeps vomiting, or becomes unsteady, contact your veterinarian or an emergency animal hospital straight away; in the US, ASPCA Animal Poison Control is available around the clock on 888-426-4435.
"Was that the travel dose or the sick dose? And is today day two?"
Cerenia is the kind of drug households get wrong by accident — two doses that look nothing alike, a two-day ceiling, and a tablet given while loading a car. SteadyTails keeps every dose, strength, time and skipped tablet on one timeline the whole household writes to. Available now on the App Store • Android coming soon.
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- U.S. Food and Drug Administration / DailyMed. CERENIA (maropitant citrate) Tablets — approved product label, Zoetis Inc. — "Administer CERENIA Tablets orally at a minimum dose of 2 mg/kg (0.9 mg/lb) body weight once daily" for prevention of acute vomiting; "Administer CERENIA Tablets orally at a minimum dose of 8 mg/kg (3.6 mg/lb) body weight once daily" for prevention of vomiting due to motion sickness in dogs "4 months of age and older"; acute vomiting "up to 5 consecutive days" in dogs 2–7 months and once daily "until resolution of acute vomiting" in dogs 7 months and older; motion sickness "up to 2 consecutive days"; "Administer CERENIA Tablets a minimum of two hours prior to travel with a small amount of food to mitigate vomiting associated with administration of the dose on an empty stomach; however, refrain from feeding a full meal prior to travel." "For prevention of acute vomiting, dispense whole or half tablets in strength(s) that most closely result in a 2 mg/kg dose"; for motion sickness, "Dispense whole or half tablets in strengths that most closely result in an 8 mg/kg dose once daily for up to 2 consecutive days". "Caution: Federal law restricts this drug to use by or on the order of a licensed veterinarian." "For oral use in dogs only". Tablet strengths 16, 24, 60 and 160 mg. Acute-vomiting dosing table (dog weight → tablets): 4 kg/8 lb → ½ × 16 mg; 8 kg/15 lb → 1 × 16 mg; 12 kg/25 lb → 1 × 24 mg; 24 kg/50 lb → 2 × 24 mg; 30 kg/65 lb → 1 × 60 mg; 60 kg/130 lb → 2 × 60 mg. Motion-sickness dosing table: 1 kg/2 lb → ½ × 16 mg; 1.5 kg/3 lb → ½ × 24 mg; 2 kg/4 lb → 1 × 16 mg; 3 kg/6 lb → 1 × 24 mg; 4 kg/8 lb → 2 × 16 mg; 6 kg/13 lb → 2 × 24 mg; 7.5 kg/16 lb → 1 × 60 mg; 10 kg/22 lb → ½ × 160 mg; 15 kg/33 lb → 2 × 60 mg; 20 kg/44 lb → 1 × 160 mg; 30 kg/66 lb → 1½ × 160 mg; 40 kg/88 lb → 2 × 160 mg; 60 kg/132 lb → 3 × 160 mg. Pharmacokinetics table: Tmax 2.0 h (2 mg/kg single dose) and 1.5 h (8 mg/kg single dose); Cmax 154 ng/mL and 588 ng/mL; AUC(0–24) 1440 and 6730 ng·hr/mL; terminal half-life on repeat doses 7.69 h and 25.4 h; accumulation ratio on repeat doses 2.46 and 4.81. US motion-sickness field study, CERENIA n=208 vs placebo n=195: hypersalivation 12.5% vs 9.7%, vomiting 5.3% vs 0%, muscle tremors 1% vs 0.5%, sedation/depression 1% vs 1.5%, retching 0.5% vs 1.5%, flatulence 0.5% vs 0%. "In puppies younger than 11 weeks of age, histological evidence of bone marrow hypocellularity was observed." Post-approval experience lists "anorexia, depression/lethargy, hypersalivation, vomiting, diarrhea, trembling, ataxia, allergic reactions, weight loss, convulsion, hyperactivity, and panting." dailymed.nlm.nih.gov Retrieved 2026-10-02.
- Merck Veterinary Manual. Drugs Used to Control or Stimulate Vomiting in Monogastric Animals — "Maropitant is a neurokinin-1 (NK-1) receptor antagonist approved to treat and prevent emesis in dogs and cats. Substance P is a regulatory peptide that binds to the NK-1 receptors and induces emesis." Injectable maropitant for cats ≥16 weeks at "1 mg/kg every 24 hours" and for dogs ≥8 weeks with acute vomiting at "1 mg/kg, SC, q 24 h". Tablets for dogs ≥8 weeks with acute vomiting at "2 mg/kg, PO, every 24 hours" and for dogs ≥16 weeks for motion sickness prevention at "8 mg/kg, PO, every 24 hours". "Dogs should not be fed for 1 hour before maropitant is administered. The best time to give maropitant is 2 hours before traveling, with a small amount of food." "The most common adverse effects are excessive drooling, lethargy, lack of appetite, and diarrhea." merckvetmanual.com Retrieved 2026-10-02.
- Merck Veterinary Manual. Motion Sickness in Animals — maropitant is "the preferred drug to treat motion sickness in dogs," dosed "8 mg/kg, PO, q 24 h until resolution" or injectable at 1 mg/kg SC daily. Motion sickness arises from "conflicting input from three main sensory systems that track balance and movement: the vestibular system of the inner ear, the eyes, and the body's muscles and joints," producing "nausea, vomiting, salivation, and agitation." Signs listed include "salivation, lip licking, vocalization (whining), restlessness (panting, turning, circling, digging), lethargy" with "diarrhea and vomiting" in severe cases. Alternatives given: ondansetron 0.3–1 mg/kg PO/IV every 8–12 hours; meclizine 12.5 mg per dog PO every 12 hours given 1 hour before travel; diphenhydramine 2–4 mg/kg PO every 8 hours; trazodone "5–7.5 mg/kg, PO, 90 minutes before event; can combine with gabapentin, 10 mg/kg". "Fear of the vehicle can also become a contributory factor," with signs appearing "even in stationary vehicles"; "motion sickness can be overcome by conditioning the animal to travel." merckvetmanual.com Retrieved 2026-10-02.
- VCA Animal Hospitals. Maropitant Citrate — an antiemetic for "vomiting and motion sickness in dogs and cats" which "may act as a mild pain control medication"; tablet use in cats for nausea is "off label". "This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow," with effects ending "within 24 hours, although effects can be longer in pets with liver or kidney disease." For motion sickness: "feed your pet a small meal 3 hours before traveling. Then, 1 hour later (2 hours before travel), administer maropitant citrate." "If you miss a dose, give it as soon as you remember, and then wait the recommended amount of time between doses." Common effects vomiting and hypersalivation at higher doses; rare effects decreased appetite, diarrhea, allergic reactions and uncoordinated walking; cats may show "abnormal breathing" and "recumbency (laying down and unable to get up)". Avoid in pets that "have ingested toxins," have gastrointestinal obstruction, or are under 8 weeks old. Caution with chloramphenicol, phenobarbital, NSAIDs and certain antifungals. vcahospitals.com Retrieved 2026-10-02.
- Conder GA, Sedlacek HS, Boucher JF, Clemence RG. 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. Journal of Veterinary Pharmacology and Therapeutics. 2008 Dec;31(6):528–32 — "One-hundred eighty-nine dogs with a history of motion sickness were enrolled at 26 veterinary clinics (across 12 US states) across the two trials; of these, 163 were fully evaluable, 19 were evaluable only for safety, and seven were not evaluable." "Each dog was treated orally with placebo or maropitant (minimum dose of 8 mg/kg body weight using unit dosing) tablets at approximately 2 h (Trial 1) or 10 h (Trial 2) before an automobile ride of approximately 60 min". "Maropitant reduced the occurrence of vomiting compared to placebo by 86.1% or 76.5% when given approximately 2 or 10 h prior to travel, respectively. No significant clinical signs were observed after maropitant treatment." PMID 19000275. Abstract via NCBI E-utilities: eutils.ncbi.nlm.nih.gov Retrieved 2026-10-02.
- Cited as evidence of what is currently published, not as clinical sources. VetLens, Cerenia for Dogs: Dosage, How Long It Lasts & Side Effects — "For preventing acute vomiting the labelled oral dose is 2 mg/kg once daily for up to 5 consecutive days" and "For preventing vomiting from motion sickness it is 8 mg/kg once daily for up to 2 consecutive days"; "Give 2 hours before travel"; "The label also says to fast the dog for 1 hour before giving the tablet." No weight-based dosing table, no use of the label's "minimum dose" wording, and no explanation of the two-day cap. vetlens.com · American Kennel Club, Cerenia (Maropitant) for Dogs: Uses, Side Effects, and Alternatives — "The tablet form is given at a dose of 0.9 milligrams per pound of body weight for prevention of acute vomiting, and 3.6 milligrams per pound for prevention of motion sickness"; "It should be given two hours before a car ride for optimal results." No mg/kg figures, no weight chart, no consecutive-day limits and no pre-dosing fasting instruction. akc.org · petdosagechart.com, Cerenia for Dogs: Dosage Chart, Calculator & Safety — publishes a chart on a single "2 mg per kg" standard reference across a "1–8 mg/kg" range without separating the acute-vomiting and motion-sickness indications; states "Cerenia can be given daily for up to 5 consecutive days for acute vomiting" and "for motion sickness, it is approved for up to 2 consecutive days" but draws no distinction between dogs 2–7 months and dogs 7 months and older. petdosagechart.com All retrieved 2026-10-02.