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Cerenia (Maropitant) Dosage for Cats Calculator
Cerenia (maropitant citrate) is the most widely used anti-nausea and anti-vomiting medication in cats. The dose is always 1 mg/kg once daily — but the real question most cat owners have is: which tablet size to use, and whether to split it? This calculator handles all of that. Enter your cat’s weight and reason for use to get an instant, personalised result.
⚕️ Cerenia is a prescription-only medication. This calculator is a reference based on published veterinary guidelines. Always confirm the dose, duration, and suitability with your veterinarian — especially for cats with liver disease, kittens, or cats on other medications.
🐱 Calculate Your Cat’s Cerenia Dose
My cat has liver disease
Maropitant is hepatically metabolised — dose is often reduced 50% for these catsThis is a kitten (under 6 months)
Cerenia is only approved for cats 16 weeks (4 months) and olderDosage Result
Based on published veterinary clinical guidelines
Enter your cat’s weight and select the reason for use, then tap Calculate.
📐 Dose Formula
All uses: weight (kg) × 1 mg/kg
Liver disease: dose × 0.5
(50% reduction standard)
Tablet logic:
≤ 8 mg → ½ of 16 mg tablet
9–16 mg → 1 × 16 mg tablet
17–24 mg → 1 × 24 mg tablet
>24 mg → multiple tablets / vet guidance Why is the dose the same for all uses? Unlike gabapentin, maropitant’s dose is always 1 mg/kg regardless of whether used for vomiting, motion sickness, CKD, or surgery. What differs is timing and duration — not the amount. Source: Today’s Veterinary Practice (Quimby 2020), GoodRx DVM review, FDA label (injectable).
📋 Calculation Steps
- Weight entered in kg or lb (lb auto-converts: ÷ 2.205)
- Weight × 1 mg/kg = dose in mg (e.g. 4.5 kg = 4.5 mg → rounds to nearest practical tablet)
- Liver disease: dose halved (50% reduction — hepatic metabolism via CYP450 enzymes)
- Tablet logic maps mg to closest 16 mg or 24 mg tablet, with splitting guidance
- Use-case selector changes timing, duration warnings — dose itself stays 1 mg/kg
- Kitten flag triggers safety warning — not approved under 16 weeks
Dosage Reference Chart
Cerenia Dosage for Cats by Weight
The maropitant dose for cats is always 1 mg/kg once daily, regardless of the reason for use. This chart shows the exact mg dose and the recommended tablet for every common cat weight — including how to split tablets.
| Cat Weight | Dose (1 mg/kg) | Recommended Tablet | Tablet Split | Frequency | Duration — Vomiting |
|---|---|---|---|---|---|
| 2 kg (4.4 lb) | 2 mg | ½ × 16 mg tablet | Split in half (gives 8 mg — confirm with vet) | Once daily | Up to 5 days |
| 3 kg (6.6 lb) | 3 mg | ½ × 16 mg tablet | Gives 8 mg — vet may round up to full tablet | Once daily | Up to 5 days |
| 4 kg (8.8 lb) | 4 mg | ½ × 16 mg tablet | Gives 8 mg — closest practical dose | Once daily | Up to 5 days |
| 5 kg (11 lb) | 5 mg | ½ × 16 mg tablet | Gives 8 mg — most common dose in practice | Once daily | Up to 5 days |
| 6 kg (13.2 lb) | 6 mg | ½ × 16 mg tablet | Gives 8 mg — confirms via vet | Once daily | Up to 5 days |
| 7 kg (15.4 lb) | 7 mg | ½ × 16 mg tablet | Gives 8 mg — just under full tablet range | Once daily | Up to 5 days |
| 8 kg (17.6 lb) | 8 mg | ½ × 16 mg tablet | Exact half tablet dose | Once daily | Up to 5 days |
| 10 kg (22 lb) | 10 mg | ½–1 × 16 mg tablet | Vet advises half or whole — 16 mg is slightly above | Once daily | Up to 5 days |
| 12 kg (26.5 lb) | 12 mg | ½ × 24 mg tablet or 1 × 16 mg tablet | Either option is close to calculated dose | Once daily | Up to 5 days |
| 16 kg (35 lb) | 16 mg | 1 × 16 mg tablet | Exact full tablet — no splitting needed | Once daily | Up to 5 days |
Liver Disease — Reduced Dose Reference
⚠️ Hepatic Adjustment
| Cat Weight | Standard Dose | Liver-Adjusted Dose (50% reduction) | Recommended Tablet | Notes |
|---|---|---|---|---|
| 3 kg (6.6 lb) | 3 mg | ~1.5 mg | ¼ × 16 mg tablet | Very small dose — compounded liquid may be more accurate |
| 5 kg (11 lb) | 5 mg | ~2.5 mg | ¼ × 16 mg tablet | Confirm exact approach with vet — some prefer 4 mg fixed dose |
| 6 kg (13.2 lb) | 6 mg | ~3 mg | ¼ × 16 mg tablet | Monitor for prolonged sedation or lethargy |
| 8 kg (17.6 lb) | 8 mg | ~4 mg | ¼ × 16 mg tablet | Blood tests recommended to check liver function during treatment |
| 10 kg (22 lb) | 10 mg | ~5 mg | ¼–½ × 16 mg tablet | Always vet-guided for hepatic cats |
📋 Chart Notes & Sources
- Highlighted row = average adult cat (5 kg / 11 lb) — the most common weight in practice
- Cerenia tablets come in 16 mg, 24 mg, 60 mg, and 160 mg sizes. For cats, 16 mg is the most commonly prescribed. All tablets are scored for easy splitting.
- Why do most cats get 8 mg? Because most cats weigh 3–8 kg, and the closest practical tablet is ½ of a 16 mg tablet. This is common practice — the small underdose relative to strict 1 mg/kg is clinically acceptable.
- Cerenia tablets are off-label for cats. The injectable form is FDA-approved for cats. Oral tablets are approved for dogs only — but are widely used off-label in cats at 1 mg/kg by veterinarians worldwide.
- Once a 16 mg tablet is split, use the other half within 2 days. Store unused halves in the original foil packaging at room temperature, protected from light and moisture.
- Liver disease: dose reduced approximately 50% as maropitant is hepatically metabolised via CYP2D15 and CYP3A12 enzymes. Some vets prefer a fixed low dose (e.g. 4 mg/cat) rather than weight-based reduction for hepatic cats.
- Sources: FDA injectable label (Zoetis), Today’s Veterinary Practice (Quimby 2020), VCA Animal Hospitals, GoodRx DVM review, Cats.com veterinary review, Catster DVM review
Cerenia for Cat Vomiting
1 mg/kg once daily for up to 5 days (injectable). Tablets used off-label for up to 14 days. Give with a small amount of food — not tightly wrapped.
Cerenia for Cat Travel / Motion Sickness
1 mg/kg, 2 hours before travel. Off-label use in cats. Works within 1–2 hours. Some vets prefer gabapentin for travel anxiety specifically.
Cerenia for CKD Cats
Quimby 2015 trial: 4 mg/cat orally daily for 2 weeks significantly reduced vomiting in Stage II–III CKD cats. Long-term use appears safe per pharmacokinetic studies.
Complete Guide
What Does Cerenia Do for Cats?
Uses, How It Works, Side Effects & Safety
Cerenia (maropitant citrate) is the most effective anti-vomiting medication currently available for cats. But it’s also frequently misunderstood — many owners don’t know why vomiting needs to be suppressed (rather than treated), when it’s unsafe to use, or how it compares to other options. This guide covers everything.
🧬 What Does Cerenia Do for Cats?
Cerenia is the brand name for maropitant citrate, a neurokinin-1 (NK1) receptor antagonist developed by Zoetis. It works by blocking substance P — a neuropeptide that triggers the vomiting centre in the brain. When substance P is blocked, the signal to vomit is interrupted at its source, making Cerenia highly effective across a wide range of vomiting causes.
Unlike antacids or gut-motility drugs, Cerenia acts centrally in the brain rather than in the digestive tract. This means it works regardless of what’s causing the nausea — whether it’s motion sickness, chemotherapy side effects, kidney disease toxins, post-surgical nausea, or an upset stomach. It is not a treatment for the underlying cause — it stops the vomiting reflex while your vet diagnoses and treats what’s actually wrong.
Important distinction: Cerenia suppresses vomiting — it does not heal the gut, address inflammation, or treat infection. If your cat is vomiting due to IBD, pancreatitis, or kidney disease, Cerenia buys comfort and time while the underlying problem is managed separately.
Vets prescribe Cerenia for cats in these situations:
- Acute vomiting — gastroenteritis, dietary indiscretion, chemotherapy-related nausea, toxin-induced vomiting
- CKD-associated nausea and vomiting — uremic toxins trigger the chemoreceptor trigger zone; Cerenia blocks this pathway effectively
- Motion sickness / travel nausea — off-label use, given 2 hours before travel
- Pre/post-surgical nausea — prevents opioid- and anaesthesia-induced vomiting; also provides mild visceral pain adjunct benefit
- Chronic vomiting in IBD or pancreatitis — as part of a multi-drug management plan under vet supervision
⏱️ How Long Does Cerenia Take to Work — and How Long Does It Last?
How quickly Cerenia works depends on the form used. The injectable version begins working within minutes. Oral tablets take longer to absorb.
30m
30–60 minutes — tablets begin absorbing
Maropitant reaches detectable plasma levels within 30–60 minutes of oral administration. Bioavailability in cats is approximately 50%, which is why the oral dose matches the injectable dose — unlike in dogs, who need double the oral dose to compensate for lower bioavailability.2h
1–2 hours — full effect (oral tablets)
Peak plasma concentration is typically reached within 2.5 hours after oral dosing. For motion sickness, give Cerenia 2 hours before travel to ensure full effect during the journey.24h
How long does Cerenia last in cats?
Each dose of Cerenia lasts approximately 24 hours, which is why it’s given once daily. The terminal half-life is 13–17 hours in cats. This means dosing once every 24 hours maintains continuous anti-nausea coverage. In cats with liver disease, the drug may last longer due to slower hepatic clearance. ⚠️ Cats with liver or kidney disease may experience prolonged drug effects beyond 24 hours. If your cat seems excessively lethargic the day after a Cerenia dose, report this to your vet.
⚖️ Cerenia vs Other Anti-Nausea Options for Cats
Cerenia is the most commonly used antiemetic for cats, but it’s not the only option. Here’s how it compares to the main alternatives vets consider:
| Medication | How It Works | Best For | Key Limitation |
|---|---|---|---|
| Cerenia (maropitant) | Blocks substance P at NK1 receptor in brain | Most types of vomiting; CKD nausea; surgical nausea | Prescription only; not suitable if GI obstruction suspected |
| Ondansetron (Zofran) | Blocks serotonin (5-HT3) receptor | Chemotherapy nausea; sometimes used alongside Cerenia | Off-label in cats; less evidence for general vomiting |
| Gabapentin | Calms CNS — sedation, not anti-nausea | Travel anxiety in cats; vet-visit stress | Does not target nausea or vomiting directly |
| Mirtazapine | Antiemetic + appetite stimulant | CKD cats with both nausea and poor appetite | Affects mood and appetite — not a standalone antiemetic |
| Metoclopramide | Dopamine antagonist + gut motility | Gastric motility disorders | Less effective for cats than Cerenia; more side effects |
For most cats with acute vomiting, Cerenia is the first-line choice. For CKD cats with poor appetite alongside vomiting, vets often combine Cerenia with mirtazapine.
⚠️ Cerenia Side Effects in Cats
Cerenia is generally very well tolerated in cats — it has one of the better safety profiles among prescription veterinary medications. Side effects are usually mild and short-lived.
Common (mild, expected)
- Lethargy or mild drowsiness
- Decreased appetite temporarily
- Hypersalivation / drooling
- Pain/sting at injection site
- Soft stools or mild diarrhoea
Rare — monitor and report
- Muscle tremors or ataxia
- Abnormal breathing
- Hematuria (blood in urine)
- Allergic reaction (swelling, hives)
- Prolonged sedation (>24 hrs)
Stop and call vet if you see
- Difficulty breathing
- Severe weakness or collapse
- Facial swelling or hives
- Symptoms not resolving after 24 hrs
Long-term safety
- No organ toxicity at standard doses
- Long-term use appears safe (pharmacokinetic studies)
- Does not affect kidney function directly
- Monitor liver values with prolonged use
ℹ️ The most common complaint for injectable Cerenia is stinging pain at the injection site, which affects roughly one in three cats. Refrigerating the vial before injection has been shown to reduce this. The pain is transient and fades within a minute.
🛡️ When Should Cerenia NOT Be Given to Cats?
Cerenia is safe for most cats, but there are specific situations where it must not be used, or where careful precaution is needed:
🚫
Never use Cerenia if GI obstruction is suspected. Cerenia works by suppressing the vomiting reflex. If a cat has a blockage in the stomach or intestines, vomiting is a critical warning sign. Suppressing it can mask a life-threatening obstruction and allow the gut to rupture. Your vet must rule this out before prescribing.
🚫
Never use if your cat recently swallowed a toxin. Vomiting is the body’s mechanism to expel ingested poison. Blocking this reflex with Cerenia when a toxin is still in the stomach can worsen toxicity significantly.
- Kittens under 16 weeks — not approved for this age group due to immature liver function
- Pregnant or nursing cats — safety not established; avoid unless benefit clearly outweighs risk
- Liver disease — use with caution; dose should be reduced by 50% as maropitant is hepatically metabolised
- Heart disease — maropitant affects calcium and potassium channels; use cautiously in cats with known cardiac conditions
- Drug interactions — Cerenia is metabolised via CYP450 liver enzymes. Tell your vet if your cat takes antifungals (fluconazole), phenobarbital, amlodipine, diltiazem, fluoxetine, or NSAIDs — these may interact
✓ Cerenia does not cause organ damage at standard doses, and no significant liver or kidney toxicity has been reported in cats at prescribed doses. Pharmacokinetic and toxicity studies in cats indicate that longer-term use appears safe when used under veterinary supervision.
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Frequently Asked Questions
Cerenia for Cats — FAQ
Answers to the most commonly searched questions about Cerenia dosage, how fast it works, how long it lasts, safety for CKD cats, and when it should not be used.
💊 Dosage
1
What is the correct Cerenia dosage for cats? The maropitant (Cerenia) dose for cats is 1 mg/kg once daily for all uses — vomiting, motion sickness, CKD nausea, or surgical nausea. This dose does not change between conditions; only the timing and duration differ. Some practical examples:
- 3–8 kg cat → ½ × 16 mg tablet (gives 8 mg — closest practical dose)
- 10–16 kg cat → 1 × 16 mg tablet
- Liver disease cats → dose reduced approximately 50% by your vet
2
Why is the Cerenia tablet dose the same as the injection dose in cats, but double in dogs? This is a genuinely interesting pharmacological difference. Cats have approximately 50% oral bioavailability for maropitant, meaning half of the oral dose is absorbed into the bloodstream. Dogs have only about 23.7% oral bioavailability — so dogs need roughly double the oral dose to achieve the same plasma concentration as an injection. Since cats absorb the tablet much more efficiently, they use the same 1 mg/kg dose for both oral and injectable forms. This is also why the Cerenia tablet is off-label for cats but works very effectively at the same dose rate.
3
Can Cerenia be given with food? Yes — give Cerenia with a small amount of food, but not a large meal. Cerenia tablets should be loosely covered in food (like a small piece of wet food or a pill pocket) when given for vomiting — wrapping it too tightly may reduce how well it’s absorbed. For motion sickness, give the tablet as a small snack with a light amount of food about 2 hours before travel — not a full meal, which could increase the risk of stomach upset during travel.
⏱️ Timing & Duration
4
How long does it take for Cerenia to work in cats? Oral Cerenia tablets take 1 to 2 hours to reach full effect in cats. Peak plasma concentration is typically reached within 2.5 hours after an oral dose. This is why vets recommend giving it 2 hours before travel for motion sickness. Injectable Cerenia given by your vet begins working within minutes. If your cat vomits shortly after being given a Cerenia tablet, contact your vet — they may re-dose or switch to an injection.
5
How long does Cerenia last in cats? Each dose of Cerenia provides approximately 24 hours of anti-nausea coverage — which is why it’s given once daily. The terminal half-life is 13–17 hours in cats. This means the drug stays active at meaningful levels throughout the day after a single morning dose. Cats with liver disease may have extended drug effects because maropitant is cleared through the liver — these cats may experience sedation or lethargy lasting longer than 24 hours.
6
How many days can a cat be on Cerenia? The injectable form is FDA-approved for up to 5 consecutive days for acute vomiting. Oral tablets used off-label can be given for up to 14 days in many cases. For CKD or chronic vomiting conditions, vets often prescribe Cerenia on an ongoing basis — this is supported by a 2015 clinical trial showing safe and effective use over a 2-week period, and pharmacokinetic studies suggesting longer-term safety. However, long-term use should always be supervised by your vet, with periodic liver function monitoring.
🛡️ Safety & Special Cases
7
Is Cerenia safe for cats with CKD (kidney disease)? Yes, Cerenia can be used safely in cats with CKD. A 2015 randomised, placebo-controlled trial (Quimby et al., Journal of Feline Medicine and Surgery) found that oral maropitant at 4 mg per cat daily for 2 weeks significantly reduced vomiting in cats with IRIS Stage II and III CKD, with no significant adverse effects on kidney values. Because CKD cats often experience nausea from uremic toxins triggering the brain’s vomiting centre (CRTZ), Cerenia’s central mechanism makes it particularly well-suited. If your CKD cat’s appetite also remains poor, ask your vet about adding mirtazapine as an appetite stimulant alongside Cerenia.
8
Can I give my cat Cerenia for travel and motion sickness? Cerenia is widely used off-label in cats for travel nausea, but it is not officially approved for motion sickness in cats (unlike in dogs). It works for the nausea component of travel. However, if your cat’s main issue is anxiety and stress during travel — rather than physical nausea — gabapentin may be a better fit, as it directly addresses the fear and anxiety response. Discuss with your vet which issue is primary for your cat. Give Cerenia 2 hours before travel if using it for motion sickness.
9
What happens if a cat is given too much Cerenia? Cerenia has a relatively wide safety margin in cats. An overdose typically causes excessive lethargy, weakness, drooling, and loss of coordination. In severe overdose cases, breathing difficulties have been reported. There is no specific antidote — treatment is supportive. If you suspect your cat has received too much Cerenia, contact your vet or emergency animal clinic immediately. Do not attempt to induce vomiting unless explicitly instructed by a vet, as Cerenia itself suppresses the vomiting reflex.
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