フィロコキシブ
Firocoxib
3-(cyclopropylmethoxy)-5,5-dimethyl-4-(4-methylsulfonyl) phenylfuran-2(5H)-one
別名: Previcox · Equioxx · ML-1,785,713 · Firocoxibum
VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
動物種別用量
🌎 NA — North America🌍 EU — Europe
犬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Control of pain and inflammation associated with osteoarthritis | 5 mg/kg (2.27 mg/lb) | PO | once daily | — | 🌎 NA |
| Pain and inflammation (osteoarthritis, surgery) | 5 mg/kg | PO | q24h | As directed (monitor carefully if >90 days) | 🌍 EU |
- Control of pain and inflammation associated with osteoarthritis: Dosage should be calculated in half tablet increments and can be administered with or without food.
- Pain and inflammation (osteoarthritis, surgery): Give with or without food. For perioperative pain, give the first dose 2 hours before surgery.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Experimentally induced pyrexia (Unapproved/Investigational) | 0.75-3 mg/kg | PO | single dose | single dose | 🌎 NA |
| Contraindicated | Do not use | PO | N/A | N/A | 🌍 EU |
- Experimentally induced pyrexia (Unapproved/Investigational): 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: Strictly contraindicated in cats.
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Control of pain and inflammation associated with osteoarthritis | 0.1 mg/kg (0.045 mg/lb) body weight | PO | daily | up to 14 days | 🌎 NA |
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
概要
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.
安全性・警告
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)
注意事項
Important Washout Period: If changing from one NSAID to another, a washout period is required. A 24-hour washout is often recommended between COX-2 selective agents, but 72 hours to 1 week is usually recommended when switching from a non-selective NSAID or aspirin.
- Use with caution and enhanced monitoring in patients with pre-existing renal, hepatic, or cardiovascular dysfunction.
- Use with caution in patients that are dehydrated, hypovolemic, hypotensive, or on concomitant diuretic therapy due to increased risk of renal toxicity.
- Geriatric patients require ongoing monitoring due to naturally reduced renal function.
- Puppy Toxicity: Doses above the recommended 5 mg/kg in puppies less than 7 months old have been associated with serious adverse reactions, including hepatic fatty changes and death.
医薬品相互作用
Some NSAIDs can reduce effects on blood pressure
May increase the risk of gastrointestinal toxicity (ulceration, bleeding, vomiting, diarrhea)
May increase the risk of gastrointestinal toxicity (ulceration, bleeding, vomiting, diarrhea)
NSAIDs may increase serum levels
Administration has increased plasma levels of celecoxib in humans and potentially could also affect firocoxib levels in dogs
NSAIDs may reduce the saluretic and diuretic effects
May displace other highly bound drugs or be displaced by them, potentially increasing serum levels, duration of action, and toxicity
Serious toxicity has occurred when NSAIDs have been used concomitantly; use together with extreme caution
May enhance the risk of nephrotoxicity development
Increased risk of severe gastrointestinal ulceration and renal toxicity. A 3-5 day wash-out period is required.
Synergistic gastrointestinal toxicity leading to severe ulceration or perforation.
Increased risk of nephrotoxicity.
Potential synergistic efficacy in treating transitional cell carcinomas.
Increased risk of gastrointestinal ulceration and bleeding.
Increased risk of nephrotoxicity.
監視
- 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)
薬物動態
半減期
吸収
Dogs: Oral bioavailability is ~38% (chewable tablets). Food delays but does not affect the amount absorbed. Peak levels occur at 1 hour (fasted) or 5 hours (fed). Horses: Oral bioavailability is ~79% (paste). Peak levels occur 4-12 hours post-dose. Cats: Oral bioavailability is ~60% (suspension).
分布
Dogs: Vd is ~3 L/kg; 96% bound to plasma proteins. Horses: Vd is 1.7-2.3 L/kg; 98% bound to plasma proteins. Cats: Vd is 2-3 L/kg.
代謝
Dogs: Biotransformation occurs predominantly via dealkylation and glucuronidation in the liver. Horses: Biotransformation occurs primarily via decyclopropylmethylation and then glucuronidation.
消失
Dogs: Elimination is principally in the bile and feces. Horses: Metabolites are primarily excreted in the urine.
過剰投与
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.
製品
製剤
- Chewable tablets
- Oral paste
- 57 mg oral tablet
- 227 mg oral tablet
動物用医薬品
- Firocoxib Chewable Tablets (scored): 57 mg & 227 mg; Previcox (Merial)
- Firocoxib Oral Paste: 0.82% w/w (8.2 mg firocoxib per gram of paste) in a 6.93 gram oral syringe; Equioxx (Merial)
- Previcox 57 mg chewable tablets
- Previcox 227 mg chewable tablets
規制ステータス
POM-V classification.
POM-V classification.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Commercially available tablets and oral paste should be stored at room temperature (15-30°C); brief excursions are permitted up to 40°C (104°F).
飼主向け情報
- 投与方法: 食事の有無にかかわらず投与できます。胃腸の不調が見られる場合は、食事と一緒に与えると良い場合があります。
- 犬の観察すべき点: 嘔吐、食欲低下/体重減少、下痢や軟便、行動や活動の変化、飲水量や排尿量の変化、または白目や粘膜の黄疸に気づいた場合は、直ちに投薬を中止し、獣医師に連絡してください。
- 馬の観察すべき点: 舌や口内の潰瘍、顔の皮膚や唇の病変、下痢/軟便、または飲食の習慣の変化が見られた場合は、獣医師に連絡してください。
-
安全上の警告: フィロコキシブを服用している間は、人間用の鎮痛剤（イブプロフェン、アセトアミノフェン、アスピリンなど）や他の獣医用NSAIDを絶対に与えないでください。致命的な胃潰瘍や腎不全を引き起こす可能性があります。
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