Mavacoxib
4-[5-(4-fluorophenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide
Also known as: Trocoxil · mavacoxibum · PHA 739,521 · UNIIYFT7X7SR77
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Pain and inflammation associated with degenerative joint disease in dogs aged 12 months or more in cases where continuous treatment exceeding one month is indicated | 2 mg/kg PO given immediately before or with the dog's main meal. The treatment should be repeated 14 days later; thereafter the dosing interval is one month. | PO | Day 1, Day 14, then monthly | A treatment cycle should not exceed 7 consecutive doses (6.5 months). | 🌎 NA |
| Pain and inflammation associated with degenerative joint disease (osteoarthritis) | 2 mg/kg | PO | q14d for 2 doses, then q1month | Maximum of 7 doses total | 🌍 EU |
- Pain and inflammation associated with degenerative joint disease in dogs aged 12 months or more in cases where continuous treatment exceeding one month is indicated: Care should be taken to ensure that the tablet is ingested. THIS IS not a daily NSAID.
- Pain and inflammation associated with degenerative joint disease (osteoarthritis): Should be given immediately before or with the dog's main meal. Treatment can potentially be re-started after a 1-month break from dosing.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Any | Do not use | PO | N/A | N/A | 🌍 EU |
- Any: Contraindicated in cats.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Mavacoxib is a highly unique, ultra-long-acting non-steroidal anti-inflammatory drug (NSAID) of the coxib class. Unlike traditional daily NSAIDs, mavacoxib is designed for monthly administration, making it an excellent choice for patients whose owners struggle with daily dosing compliance.
Clinical Pearl: Because of its exceptionally long half-life (averaging 16-17 days), any adverse effects may persist for weeks after the drug is discontinued. Therefore, careful patient selection is critical, and it is generally reserved for chronic osteoarthritis management rather than acute pain.
Mechanism of action
Mavacoxib is a COX-2 selective inhibitor (coxib).
- Arachidonic Acid Cascade: It selectively inhibits the cyclooxygenase-2 (COX-2) enzyme → decreases the production of pro-inflammatory prostaglandins (such as PGE2) → reduces pain, inflammation, and fever.
- COX-1 Sparing: At therapeutic dosages, it relatively spares COX-1, the constitutive enzyme responsible for synthesizing prostaglandins that protect the gastric mucosa, support platelet function, and maintain normal renal blood flow. However, COX-selectivity is relative and can be lost at higher doses or in susceptible individuals.
Safety & warnings
Contraindications
- Dogs less than 12 months of age
- Dogs less than 5 kg body weight
- Gastrointestinal disorders including ulceration and bleeding
- Evidence of a hemorrhagic disorder
- Impaired renal or hepatic function
- Cardiac insufficiency
- Hypersensitivity to mavacoxib, sulfonamides, or excipients
- Pregnant, breeding, or lactating animals
- Dehydrated, hypovolemic, or hypotensive animals
- Dehydrated, hypovolaemic, or hypotensive patients
- Gastrointestinal disease or ulceration
- Blood clotting disorders
- Liver disease (prolongs metabolism and causes accumulation)
- Renal disease (requires careful evaluation, generally avoid)
- Pregnant or lactating animals
- Dogs < 12 months of age
- Dogs < 5 kg body weight
- Cats
Adverse effects
- Inappetence
- Diarrhea
- Depression
- Gastrointestinal ulceration or bleeding
- Vomiting and diarrhoea
- Renal toxicity (especially if dehydrated or hypotensive)
- Hepatic accumulation (in poor metabolizers)
- Theoretical risk of precipitating cardiac failure
Precautions
Do not use concomitantly with glucocorticoids or other NSAIDs. Do not administer other NSAIDs within 1 month of the last administration of mavacoxib. Avoid use in any dehydrated, hypovolemic, or hypotensive animal, as there is a potential risk of increased renal toxicity. Concurrent administration of potentially nephrotoxic medicinal products should be avoided. Animals should not become dehydrated when receiving this or other NSAIDs.
Drug interactions
NSAIDs can reduce effects on blood pressure and potentially reduce renal blood flow, increasing the risk for renal injury.
May increase the risk of gastrointestinal toxicity (ulceration, bleeding, vomiting, diarrhea). Long washout periods are warranted when switching.
May increase the risk of gastrointestinal toxicity (ulceration, bleeding, vomiting, diarrhea). Concurrent use is contraindicated.
NSAIDs may increase serum levels of digoxin.
May increase plasma levels of mavacoxib (extrapolated from celecoxib data in humans).
NSAIDs may reduce saluretic and diuretic effects.
Serious toxicity has occurred when NSAIDs have been used concomitantly; use together with extreme caution.
May enhance the risk of nephrotoxicity development.
May increase the risk of gastrointestinal toxicity. Do not administer other NSAIDs within 1 month of the last administration of mavacoxib.
Increased risk of severe gastrointestinal ulceration and bleeding.
Increased risk of nephrotoxicity.
Synergistic risk of acute kidney injury.
Monitoring
- Baseline and periodic CBC and serum chemistry (including BUN/serum creatinine, and liver function assessment)
- Baseline history and physical
- Efficacy of therapy
- Adverse effect monitoring via client
- Baseline and periodic renal function (BUN, Creatinine, SDMA, USG)
- Baseline and periodic hepatic function (ALT, ALP, Bilirubin)
- Clinical signs of GI ulceration (vomiting, melaena, anorexia)
- Hydration status and blood pressure (especially during anaesthesia)
Pharmacokinetics
Half-life
Absorption
Average bioavailability after oral dosing is about 46% when fasted, but nearly doubles (87%) when given with food. Peak levels occur in about 11 hours.
Distribution
Apparent volume of distribution (steady-state) averaged 1.6 L/kg. Highly bound to canine plasma proteins (98%).
Metabolism
Primarily cleared by biliary excretion.
Elimination
Total body clearance is a very low 2.7 mL/hour/kg.
Overdose
In safety studies, repeated doses of 5 and 10 mg/kg did not demonstrate adverse events. At 15 mg/kg, vomiting, softened/mucoid feces, and decreased renal function were noted. Doses of 25 mg/kg caused GI ulceration, with one fatality from GI perforation and peritonitis.
- Management: Manage as with other NSAID toxicity (emetics, activated charcoal, GI protectants, fluid diuresis).
- Important: Because of the drug's very long duration of effect, prolonged monitoring and treatment may be required. Consulting a veterinary poison center is highly recommended.
Available products
Formulations
- Oral chewable tablets
- 6 mg chewable tablet
- 20 mg chewable tablet
- 30 mg chewable tablet
- 75 mg chewable tablet
- 95 mg chewable tablet
Veterinary
- Mavacoxib Oral Chewable Tablets: 6 mg, 20 mg, 30 mg, 75 mg, & 95 mg (Trocoxil)
- Trocoxil 6 mg chewable tablets
- Trocoxil 20 mg chewable tablets
- Trocoxil 30 mg chewable tablets
- Trocoxil 75 mg chewable tablets
- Trocoxil 95 mg chewable tablets
Regulatory status
Authorized for use in dogs >= 12 months old.
POM-V classification.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store in the original packaging at room temperature out of reach of pets and children.
Client information
CRITICAL WARNING: This is NOT a daily medication. Give exactly as directed by your veterinarian (typically a dose on Day 1, Day 14, and then strictly once a month). Do not give extra doses.
- Give with Food: Must be given with the dog's largest meal of the day. The drug is much better absorbed from the stomach if given with food.
- Watch for Side Effects: Contact your veterinarian immediately if you notice loss of appetite, vomiting, bloody or dark/tarry stools, changes in behavior, or changes in drinking/urination. Note: Because this drug lasts a long time in the body, side effects could potentially occur weeks after the last dose was given.
- Safe Storage: These chewable tablets are highly palatable to dogs. Store them strictly out of reach of all animals and children to prevent accidental overdose.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.