フルニキシンメグルミン
**フルニキシンメグルミン**は、強力な獣医専用の非ステロイド性抗炎症薬（NSAID）であり、鎮痛、抗炎症、解熱作用のために広く使用されています。 * **主な用途**: 米国では馬、牛、豚での使用がFDAに承認されています。馬では、**疝痛（コリック）**に関連する内臓痛に対する標準的な鎮痛薬とされており、筋骨格系疾患にも使用されます。牛や豚では、主に呼吸器疾患やエンドトキシン血症に伴う発熱のコントロールに使用されます。 * **適応外使用**: 過去には小動物（犬）にも使用されていましたが、現在ではより安全なCOX-2選択的NSAID（カルプロフェン、メロキシカムなど）に取って代わられています。猫はNSAIDの毒性に対して非常に敏感であるため、通常は禁忌とされます。 * **臨床のポイント**: フルニキシンは、敗血症性ショックの動物の血行動態を改善する能力や、反芻動物および馬の内臓痛に対する高い有効性で知られています。ただし、疝痛患者において、エンドトキシン血症や腸管壊死に関連する行動的および心肺の兆候を隠してしまう可能性があります。
作用機序: Flunixin meglumine is a potent, non-selective inhibitor of the **cyclooxygenase (COX)** enzyme system. * **Mechanism**: Cell membrane phospholipids → **Phospholipase A2** → Arachidonic Acid → **COX-1 / COX-2** → Decreased production of **prostaglandins** and **thromboxanes**. * By inhibiting prostaglandin synthesis, it reduces inflammation, lowers body temperature (antipyretic), and provides significant analgesia. * Unlike some other NSAIDs, flunixin does not appreciably alter gastrointestinal motility in horses, making it highly suitable for colic management.
動物種別の用量
- As an analgesic · 1-2 mg/kg · IV · q24h
- As an analgesic (oral paste) · 1-4 mg/kg · PO · once daily
- As an analgesic · 1-2 mg/kg · IV · q24h
- As an analgesic (oral paste) · 1-4 mg/kg · PO · once daily
- General · 0.5-2 mg/kg · PO or IM · one time daily
- For labeled indications · 1.1-2.2 mg/kg (1-2 mL per 100 lbs. BW) · slow IV · once a day as a single dose or divided into two doses q12h · up to 3 days · Avoid rapid IV administration
- As an analgesic · 1.1-2.2 mg/kg · IV · q6-12 hours · Recommend 72 hour milk withdrawal at this dose rate
- As an analgesic for visceral pain · 0.25-1 mg/kg · IV · q12-24h
- Using combination product (Resflor Gold) · 40 mg/kg florfenicol/2.2 mg/kg flunixin (6 mL/100 lb. B.W.) · SC · once · Do not administer more than 10 mL at each site. Injection should be given only in the neck.
投与経路
禁忌
- Known hypersensitivity to flunixin
- Cats (generally contraindicated due to availability of safer alternatives)
- Patients with preexisting GI ulcers (e.g., Equine Gastric Ulcer Syndrome - EGUS)
- Patients with significant renal, hepatic, or hematologic diseases
- Breeding bulls (lack of reproductive safety data)
- Use to ambulate cattle intended for slaughter
有害事象
- Anaphylaxis (especially after rapid IV administration in horses and cattle)
- IM injection site reactions (localized swelling, induration, stiffness, sweating, and rarely clostridial myonecrosis)
- Gastrointestinal ulceration (oral and gastric ulcers, especially with prolonged use or high doses)
- Renal ischemia and nephrotoxicity (especially in dehydrated patients, dogs, and birds)
- Hematochezia and hematuria (reported in cattle treated > 3 days)
- Hypoproteinemia and hematologic abnormalities
薬物相互作用
- Aspirin · May decrease plasma levels of flunixin and increase the likelihood of GI adverse effects (blood loss)
- 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
- Enrofloxacin · Increases AUC and elimination half-life of both flunixin and enrofloxacin in dogs
- Furosemide & other diuretics · May reduce the saluretic and diuretic effects of the diuretic
- Methotrexate · Serious toxicity has occurred with concomitant use; use together with extreme caution
- Nephrotoxic agents (e.g., aminoglycosides, amphotericin B) · Increased risk of synergistic nephrotoxicity
- Probenecid · May cause a significant increase in serum levels and half-life of flunixin
- Warfarin · May increase the risk for bleeding
モニタリング
- Analgesic, anti-inflammatory, and antipyretic efficacy
- Gastrointestinal effects (especially in dogs and horses)
- CBCs and occult blood in feces with chronic use in horses
- Renal parameters (BUN, Creatinine, USG) in susceptible species or dehydrated patients
過量投与
Acute overdosage should be handled by using established protocols of emptying the gut (if oral ingestion and practical/possible) and treating the patient supportively. * **Gastric Ulceration**: A distinct possibility in horses that have received overdoses. Consider using prophylactic anti-ulcer medications (e.g., omeprazole) in overdosed horses. * **Renal Protection**: Ensure adequate hydration and monitor renal values closely.
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。