エトドラク
**エトドラク**は、主に犬の**変形性関節症**に伴う疼痛および炎症の管理に獣医療で使用される非ステロイド性抗炎症薬（NSAID）です。 * 経口錠剤および注射剤の形態で利用可能です。 * 犬において比較的長い半減期を持ち、便利な**1日1回投与**が可能です。 * **臨床上のポイント**: 有効である一方で、一部の新しい獣医用NSAIDと比較して治療域が狭いため、胃腸毒性を避けるためには正確な用量設定が不可欠です。治療用量のわずか2.7倍で胃腸障害を引き起こす可能性があります。
作用機序: 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.
動物種別の用量
- 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.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- 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)
有害事象
- 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)
薬物相互作用
- 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.
モニタリング
- 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
過量投与
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 の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。