Etodolac
**Etodolac** is a non-steroidal anti-inflammatory drug (NSAID) primarily utilized in veterinary medicine for the management of pain and inflammation associated with **osteoarthritis** in dogs. * Available in both oral tablet and injectable formulations. * Characterized by a relatively long half-life in dogs, allowing for convenient **once-daily dosing**. * **Clinical Pearl**: While effective, etodolac has a narrower therapeutic index compared to some newer veterinary NSAIDs (e.g., carprofen, meloxicam), meaning precise dosing is critical to avoid gastrointestinal toxicity. Doses as little as 2.7X the therapeutic dose can produce gastrointestinal lesions.
Mechanism: Etodolac exerts its analgesic, anti-inflammatory, and antipyretic effects primarily by inhibiting the **cyclooxygenase (COX)** enzymes. * **Arachidonic Acid → Prostaglandins**: By blocking COX, etodolac prevents the conversion of arachidonic acid into pro-inflammatory prostaglandins. * It is generally considered a **COX-1 sparing** drug rather than highly COX-2 selective in dogs. In horses, it does not exhibit much COX-2 selectivity. * Additionally, etodolac inhibits **macrophage chemotaxis**, which further blunts the inflammatory cascade at the site of tissue injury.
Dosing by species
- Treatment of pain and inflammation associated with osteoarthritis · 10-15 mg/kg · PO · once daily · Dogs less than 5 kg cannot be accurately dosed with EtoGesic tablets. Adjust dose to obtain satisfactory response, but do not exceed 15 mg/kg. For long-term therapy, reduce dose level to minimum effective dosage.
- Treatment of pain and inflammation associated with osteoarthritis · 10-15 mg/kg · SC · once · Administer as a dorsoscapular subcutaneous injection. If needed, daily doses of tablets may begin 24 hours after the last injectable treatment. Use alternate injection sites.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Known hypersensitivity to etodolac
- Dogs less than 12 months of age
- Breeding, pregnant, or lactating dogs (safe use not established)
- Cats (highly sensitive to toxicity)
Adverse effects
- Vomiting
- Regurgitation
- Diarrhea
- Lethargy
- Hypoproteinemia
- Urticaria
- Behavioral changes
- Inappetence
- Hepatotoxicity (rare)
- Nephrotoxicity (rare)
- Localized pain or tissue reactions at injection site
- Decreased total serum T4
- Keratoconjunctivitis sicca (KCS)
Drug interactions
- ACE Inhibitors (enalapril, benazepril) · May reduce antihypertensive effects and increase the risk for renal injury.
- Aspirin · May decrease etodolac plasma levels and increase likelihood of GI adverse effects (blood loss). Concomitant use is not recommended.
- Cyclosporine · May increase cyclosporine blood levels and increase the risk for nephrotoxicity.
- Digoxin · May increase serum levels of digoxin. Use with caution in severe cardiac failure.
- Furosemide & other diuretics · May reduce the saluretic and diuretic effects of furosemide.
- Methotrexate · Serious toxicity has occurred with concomitant NSAID use.
- Nephrotoxic agents (amphotericin B, aminoglycosides, cisplatin) · Potential for increased risk of nephrotoxicity.
- Phenobarbital · May increase the metabolism of etodolac in dogs.
- Probenecid · May cause a significant increase in serum levels and half-life of etodolac.
- Warfarin · May increase the risk for bleeding.
Monitoring
- Baseline physical exam, CBC, Serum chemistry panel (liver and renal function), and Urinalysis
- Reassess liver enzymes at one week of therapy
- Tear production (Schirmer Tear Test) prior to and during therapy due to KCS risk
- Clinical efficacy (pain scoring)
- Signs of adverse reactions: inappetence, vomiting, melena, diarrhea, PU/PD, jaundice, lethargy
Overdose
Etodolac has a relatively **narrow therapeutic window** in dogs. * **2.7X overdose (40 mg/kg/day)**: Can cause GI ulcers, weight loss, emesis, and local occult blood. * **5.3X overdose (80 mg/kg/day)**: Highly lethal; caused death or moribund state secondary to severe GI ulceration in safety studies. * **Feline Toxicity**: Cats are highly sensitive. Exposures have resulted in acute renal failure, anorexia, collapse, hyperkalemia, and hypersalivation. **Treatment**: Decontamination with emetics and/or activated charcoal may be appropriate for acute ingestions. Use gastrointestinal protectants for expected GI effects. If renal effects are anticipated, aggressive fluid diuresis is warranted.
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.