Flunixin Meglumine
**Flunixin meglumine** is a potent, veterinary-only non-steroidal anti-inflammatory drug (NSAID) widely used for its analgesic, anti-inflammatory, and antipyretic properties. * **Primary Uses**: It is FDA-approved in the US for horses, cattle, and swine. In horses, it is considered a gold-standard analgesic for visceral pain associated with **colic** and is also used for musculoskeletal disorders. In cattle and swine, it is primarily used to control pyrexia associated with respiratory diseases and endotoxemia. * **Extra-label Use**: While historically used in small animals (dogs), its use has been largely supplanted by newer, safer, COX-2 preferential/selective NSAIDs (e.g., carprofen, meloxicam). It is generally considered contraindicated in cats due to high sensitivity to NSAID toxicity. * **Clinical Pearl**: Flunixin is particularly noted for its ability to improve hemodynamics in animals with septic shock and its profound efficacy against visceral pain in ruminants and equines. However, it can mask behavioral and cardiopulmonary signs of endotoxemia or intestinal devitalization in colic patients.
กลไกการออกฤทธิ์: 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.
ขนาดยาตามชนิดสัตว์
- 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.
วิธีการให้ยา
ข้อห้ามใช้
- 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
อาการไม่พึงประสงค์
- 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
อันตรกิริยาระหว่างยา
- 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
การติดตาม
- 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
การได้รับยาเกินขนาด
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.
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