Meloxicam
**Meloxicam** is a widely utilized **non-steroidal anti-inflammatory drug (NSAID)** belonging to the oxicam class. It is primarily prescribed in veterinary medicine for the management of pain and inflammation associated with osteoarthritis, as well as for post-operative pain control. Key properties include: * **Analgesic:** Reduces pain perception. * **Anti-inflammatory:** Decreases tissue inflammation. * **Antipyretic:** Lowers fever. > **Clinical Pearl:** Meloxicam is highly favored in small animal practice due to its convenient once-daily dosing and the availability of a highly palatable oral liquid suspension, which allows for precise, easily titrated dosing based on the patient's exact body weight.
กลไกการออกฤทธิ์: Meloxicam exerts its therapeutic effects primarily through the **inhibition of cyclooxygenase (COX)** enzymes, which are responsible for synthesizing prostaglandins from arachidonic acid. **Arachidonic Acid** → **COX Enzymes** → **Prostaglandins & Thromboxanes** * **COX-1 (Constitutive):** Produces prostaglandins that protect the gastric mucosa, maintain normal renal blood flow, and support platelet function. * **COX-2 (Inducible):** Upregulated in response to tissue injury and inflammation, producing pro-inflammatory prostaglandins. Meloxicam is a **COX-2 preferential** (or COX-2 selective) NSAID at therapeutic doses. This means it preferentially inhibits the COX-2 enzyme, thereby reducing inflammation and pain, while largely sparing the COX-1 enzyme, which theoretically reduces the risk of gastrointestinal and renal side effects compared to non-selective NSAIDs.
ขนาดยาตามชนิดสัตว์
- Post-operative pain · 0.3 mg/kg · SC · Once · Single dose · Approved for single use only in the US.
- Chronic pain (Off-label / Non-US protocols) · 0.05 mg/kg initially, tapering to 0.01-0.02 mg/kg · PO · q24h to q48h · Chronic · Use with extreme caution; monitor renal values closely.
- Analgesia · 0.2 mg/kg · PO · q24h · As needed
- Pain and inflammation (e.g., mastitis, dehorning) · 0.5 mg/kg · SC/IV · Once · Single dose · Observe appropriate meat and milk withdrawal times.
- Musculoskeletal pain/inflammation · 0.6 mg/kg · PO/IV · q24h · Up to 14 days · Available as an oral suspension or injectable.
- Analgesia/Inflammation · 0.5 - 1.0 mg/kg · PO/IM · q12-24h · As needed · Dose varies significantly by species; higher doses often required in psittacines.
- Non-infectious locomotor disorders · 0.4 mg/kg · IM · Once · Single dose · May be repeated after 24 hours if necessary.
วิธีการให้ยา
ข้อห้ามใช้
- Patients with known hypersensitivity to meloxicam or other NSAIDs
- Active gastrointestinal ulceration or bleeding
- Pre-existing renal, hepatic, or cardiovascular dysfunction
- Hypovolemic, dehydrated, or hypotensive patients (increased risk of renal toxicity)
- Concurrent use of other NSAIDs or corticosteroids
- Bleeding disorders
- Gastrointestinal ulceration or bleeding
- Impaired hepatic, cardiac, or renal function
- Hemorrhagic disorders
- Hypersensitivity to NSAIDs
- Concurrent use of corticosteroids or other NSAIDs
- Dehydrated, hypovolemic, or hypotensive animals
อาการไม่พึงประสงค์
- Gastrointestinal upset (vomiting, diarrhea, inappetence)
- Gastrointestinal ulceration or bleeding (melena, hematemesis)
- Renal toxicity (elevated BUN/Creatinine, acute kidney injury)
- Hepatic toxicity (elevated ALT/AST, rare but possible)
- Lethargy or depression
- Vomiting
- Diarrhea
- Inappetence
- Gastrointestinal ulceration
- Renal impairment
- Hepatic enzyme elevation
อันตรกิริยาระหว่างยา
- Corticosteroids (e.g., Prednisone, Dexamethasone) · Significantly increases the risk of severe gastrointestinal ulceration and bleeding. Concurrent use is strictly contraindicated.
- Other NSAIDs (e.g., Carprofen, Deracoxib) · Additive toxicity; increases risk of GI, renal, and hepatic adverse effects. A washout period is required when switching.
- ACE Inhibitors (e.g., Enalapril, Benazepril) · May reduce the efficacy of the ACE inhibitor and increase the risk of renal toxicity.
- Furosemide · NSAIDs may reduce the diuretic effect of furosemide. · moderate
- Anticoagulants (e.g., Heparin, Warfarin) · Increased risk of bleeding complications.
- Corticosteroids · Increased risk of severe gastrointestinal ulceration and bleeding · major
- Other NSAIDs · Increased risk of gastrointestinal and renal toxicity · major
- ACE Inhibitors · Potential reduction in hypotensive effect and increased risk of renal toxicity · moderate
การติดตาม
- Baseline blood work (CBC, Chemistry panel) prior to initiating chronic therapy
- Renal values (BUN, Creatinine, SDMA, USG)
- Hepatic enzymes (ALT, AST, ALP)
- Clinical signs of GI toxicity (vomiting, diarrhea, melena, anorexia)
- Hydration status
- BUN
- Creatinine
- SDMA
- Liver enzymes (ALT, ALP)
- PCV/TP (if GI bleeding suspected)
- Clinical signs of GI upset (vomiting, diarrhea, melena)
การได้รับยาเกินขนาด
**Overdose Management:** Overdosage of meloxicam increases the risk of severe gastrointestinal ulceration, acute renal failure, and hepatic toxicity. * **Recent Ingestion (< 2 hours):** Induce emesis (if no contraindications) followed by the administration of activated charcoal to prevent further absorption. * **Gastrointestinal Protection:** Initiate GI protectants such as sucralfate, H2-receptor antagonists (e.g., famotidine), or proton pump inhibitors (e.g., omeprazole). * **Renal Protection:** Administer intravenous fluid therapy (e.g., Lactated Ringer's or 0.9% NaCl) at diuresis rates for 48-72 hours to support renal perfusion and flush the kidneys. * **Monitoring:** Monitor baseline and daily renal panel (BUN, Creatinine, Phosphorus), PCV/TP, and liver enzymes.
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