依托度酸
**依托度酸 (Etodolac)** 是一種非類固醇消炎止痛藥 (NSAID)，主要用於獸醫學中以控制犬隻與**骨關節炎**相關的疼痛和發炎。 * 提供口服錠劑與注射劑型。 * 在犬隻體內具有相對較長的半衰期，因此可以方便地**每日給藥一次**。 * **臨床要點**：雖然有效，但與一些較新的獸醫專用 NSAID 相比，依托度酸的治療指數較窄，這意味著精確的劑量對於避免胃腸道毒性至關重要。僅 2.7 倍的治療劑量就可能產生胃腸道病變。
作用機制: 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.
各物種劑量
- 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.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- 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)
不良反應
- 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)
藥物相互作用
- 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.
監測
- 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
過量
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.
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