フィロコキシブ
フィロコキシブは、**コキシブ系**に属する高選択性の**非ステロイド性抗炎症薬(NSAID)**です。 * **主な用途**: 犬および馬の**変形性関節症**に伴う疼痛および炎症の管理。 * **外科的用途**: 犬の整形外科手術後の疼痛および炎症の管理。 * **臨床的特徴**: COX-2選択的阻害薬として、非選択的NSAIDでよく見られる胃腸や腎臓への副作用を最小限に抑えつつ、強力な鎮痛効果を提供するよう設計されています。また、COX-2を発現する腫瘍において潜在的な**抗腫瘍活性**も示されており、獣医腫瘍学において役割を果たす可能性があります。
作用機序: Firocoxib exerts its analgesic, antipyretic, and anti-inflammatory effects by selectively inhibiting the **cyclooxygenase-2 (COX-2)** enzyme. * **Cellular Membrane Phospholipids** → **Arachidonic Acid** → **COX-2** → **Pro-inflammatory Prostaglandins** (e.g., PGE2). * By blocking this pathway, firocoxib reduces vasodilation, tissue edema, and sensitization of nociceptors. * **COX-1 Sparing**: At therapeutic doses, it predominantly spares the **COX-1** enzyme, which is constitutively expressed and responsible for synthesizing cytoprotective prostaglandins that maintain **gastrointestinal mucosal integrity**, **renal blood flow**, and **platelet function**.
動物種別の用量
- Experimentally induced pyrexia (Unapproved/Investigational) · 0.75-3 mg/kg · PO · single dose · single dose · Caution: While firocoxib may ultimately be shown to be safe for use in cats, supporting information (or FDA approval) is not currently available for it to be recommended.
- Contraindicated · Do not use · PO · N/A · N/A · Strictly contraindicated in cats.
- Control of pain and inflammation associated with osteoarthritis · 0.1 mg/kg (0.045 mg/lb) body weight · PO · daily · up to 14 days
- Control of pain and inflammation associated with osteoarthritis · 5 mg/kg (2.27 mg/lb) · PO · once daily · Dosage should be calculated in half tablet increments and can be administered with or without food.
- Pain and inflammation (osteoarthritis, surgery) · 5 mg/kg · PO · q24h · As directed (monitor carefully if >90 days) · Give with or without food. For perioperative pain, give the first dose 2 hours before surgery.
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
- Hypersensitivity to firocoxib or other NSAIDs
- Active GI ulcerative conditions (relative contraindication)
- Bleeding disorders or thrombocytopenia (relative contraindication)
- Dogs weighing less than 7 lbs
- Puppies less than 7 months old (US labeling) or less than 10 weeks old (UK labeling)
- Horses less than 1 year old
- Breeding, pregnant, or lactating dogs or horses (safety not established)
- Cats
- Dogs < 10 weeks of age or < 3 kg body weight
- Pregnant or lactating bitches
- Dehydrated, hypovolaemic, or hypotensive patients
- Patients with pre-existing gastrointestinal disease or bleeding
- Patients with blood clotting disorders
有害事象
- Dogs: Vomiting, decreased appetite/anorexia, diarrhea, melena, GI ulcers, bloody vomiting, GI perforation
- Dogs: Increases in BUN, creatinine, alkaline phosphatase (ALP), and ALT
- Dogs: Depression/lethargy, ataxia
- Horses: Diarrhea/loose stools, mouth ulcers, facial skin lesions, excitation (rare)
- Gastrointestinal signs (vomiting, diarrhea, inappetence)
- Gastrointestinal ulceration or bleeding
- Renal toxicity (especially during hypotensive states)
- Hepatotoxicity (rare, but liver disease prolongs metabolism)
薬物相互作用
- ACE Inhibitors (e.g., enalapril, benazepril) · Some NSAIDs can reduce effects on blood pressure
- Aspirin · May increase the risk of gastrointestinal toxicity (ulceration, bleeding, vomiting, diarrhea)
- Corticosteroids (e.g., prednisone) · May increase the risk of gastrointestinal toxicity (ulceration, bleeding, vomiting, diarrhea)
- Digoxin · NSAIDs may increase serum levels
- Fluconazole · Administration has increased plasma levels of celecoxib in humans and potentially could also affect firocoxib levels in dogs
- Furosemide · NSAIDs may reduce the saluretic and diuretic effects
- Highly Protein Bound Drugs (phenytoin, valproic acid, oral anticoagulants, sulfonamides, etc.) · May displace other highly bound drugs or be displaced by them, potentially increasing serum levels, duration of action, and toxicity
- Methotrexate · Serious toxicity has occurred when NSAIDs have been used concomitantly; use together with extreme caution
- Nephrotoxic Drugs (e.g., aminoglycosides, amphotericin B) · May enhance the risk of nephrotoxicity development
- Other NSAIDs · Increased risk of severe gastrointestinal ulceration and renal toxicity. A 3-5 day wash-out period is required. · major
- Glucocorticoids (e.g., Prednisolone, Dexamethasone) · Synergistic gastrointestinal toxicity leading to severe ulceration or perforation. · major
モニタリング
- Baseline and periodic physical exam including clinical efficacy and adverse effect queries
- Baseline and periodic CBC
- Baseline and periodic liver function tests
- Baseline and periodic renal function tests and electrolytes
- Baseline and periodic urinalysis
- Clinical signs of GI toxicity (vomiting, diarrhea, melena, anorexia)
- Renal parameters (BUN, Creatinine, USG) especially in older dogs or long-term use
- Hepatic enzymes (ALT, ALP, Bilirubin) prior to and during long-term therapy
- Hydration status and blood pressure (especially perioperatively)
過量投与
Limited information is available for acute overdoses in animals. The reported oral LD50 for rats is > 2 grams per kg. * **Management**: Should an overdose occur, contacting an animal poison control center or the manufacturer is highly recommended. * **Treatment**: Use of gut emptying protocols and supportive treatment (IV fluids, oral sucralfate, GI protectants) may be useful in managing the case.
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。