吡羅昔康
吡羅昔康是一種非類固醇消炎止痛藥 (NSAID)。雖然它具有標準的 NSAID 特性（消炎、鎮痛和退燒），但其在獸醫學中的主要用途是作為犬膀胱**移行細胞癌 (TCC)** 以及其他腫瘤（如鱗狀細胞癌和乳腺腺癌）的**輔助治療**。 > **臨床要點：** 與較新的 COX-2 選擇性 NSAID 相比，吡羅昔康在犬貓體內的治療指數非常狹窄。由於胃腸道潰瘍的風險很高，現今很少單獨用於治療骨關節炎疼痛。 它越來越多地用於**節拍式（低劑量、連續）化療**方案中，與環磷酰胺等藥物併用，透過抑制血管生成和調節免疫系統來預防肉瘤復發。
作用機制: Like other NSAIDs, piroxicam non-selectively inhibits **cyclooxygenase (COX)** enzymes, thereby blocking the conversion of arachidonic acid to **prostaglandins** and thromboxanes. This reduces inflammation and pain. Its **anti-tumor effects** are not fully understood but are believed to be indirect. Mechanisms include: * **Inhibition of COX-2** expressed by tumor cells (especially TCC) * **Anti-angiogenesis** (preventing new blood vessel formation to the tumor) * **Immune system modulation** * Inhibition of superoxide formation
各物種劑量
- Adjunctive therapy of transitional cell carcinomas · 0.3 mg/kg PO q24-72h · PO · q24-72h · Gastric protectants may be useful. Use with caution in pre-existing renal disease.
- Adjunctive therapy of transitional cell carcinomas/neoplastic diseases · 0.3 mg/kg PO every 24-48 hours · PO · q24-48h
- Cancer pain · 0.3 mg/kg PO q24-48h or 1 mg (total dose) per cat PO q24h · PO · q24-48h · Maximum of 7 days
- Antiinflammatory/analgesic · 1 mg per cat (total dose) PO once daily · PO · q24h · Maximum of 7 days
- Idiopathic chronic rhinosinusitis · 0.3 mg/kg PO once daily or every other day · PO · q24-48h
- All uses (e.g., various neoplasms) · 0.3 mg/kg · PO · q24-96h · Long-term · Start at least frequent administration and slowly increase if no side effects observed.
- Mucocutaneous squamous cell carcinoma · 80 mg (total dose) PO once daily · PO · q24h · Dose was eventually reduced to every other day or every third day due to colic signs.
- Squamous cell carcinoma of the third eyelid after surgical excision · 80 mg (total dose) PO once daily · PO · q24h
- Fracture associated limb swelling (Rabbits) · 0.1-0.2 mg/kg PO q8h · PO · q8h · 3 weeks
- Adjunctive therapy of transitional cell carcinomas, squamous cell carcinomas, and palliative therapy for other neoplastic diseases · 0.3 mg/kg PO once a day · PO · q24h
- Adjunctive therapy of neoplastic diseases (for dogs who tolerate NSAIDs poorly) · 0.3 mg/kg PO once a day. Give with food. Consider adding misoprostol at 3 micrograms/kg, PO q8h · PO · q24h · Discontinue if severe irritation or ulceration occurs.
- Adjuvant therapy for splenic hemangiosarcoma (stage II) · 0.3 mg/kg PO every day · PO · q24h · Until disease recurrence/progression · Given with Etoposide and Cyclophosphamide protocols.
- Transitional cell carcinoma after laser ablation of the primary tumor · 0.3 mg/kg PO once daily · PO · q24h · Remaining life of the dog · Given with Mitoxantrone.
- Inhibit local recurrence in dogs with incompletely resected soft tissue sarcomas · 0.3 mg/kg PO once daily · PO · q24h · Given with cyclophosphamide at 10 mg/m2 PO once daily. Decrease to every other day if unacceptable adverse effects develop.
- Antiinflammatory/analgesic · 0.3 mg/kg PO every other day (q48h) · PO · q48h
- Cancer pain · 0.3 mg/kg PO q24-48h · PO · q24-48h
- Adjunctive treatment of Idiopathic lymphoplasmacytic rhinitis (LPR) · 0.3 mg/kg PO q24h · PO · q24h · Minimum of 6 months, if not indefinitely · Combined with doxycycline or azithromycin.
- All uses (e.g., transitional cell carcinoma, prostatic carcinoma) · 0.3 mg/kg · PO · q24-72h · Long-term · Start at least frequent administration and slowly increase if no side effects observed.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Hypersensitivity to piroxicam, aspirin, or other NSAIDs
- Active or history of gastrointestinal ulcer disease
- Bleeding disorders
- Gastric ulceration
- Renal disease
- Concurrent use of corticosteroids
- Concurrent use of other NSAIDs
- Dehydration (relative contraindication due to renal risk)
不良反應
- Gastrointestinal ulceration and bleeding (melena, hematemesis)
- Vomiting, anorexia, and diarrhea
- Renal papillary necrosis
- Peritonitis (secondary to GI perforation)
- Decreased hematocrit (anecdotal in cats)
- Peripheral edema
- Elevated liver enzymes
- Gastrointestinal toxicity
- Gastric ulceration
- Ulcerative skin lesions (reported in cats)
- Potential precipitation of cardiac failure (known in humans, unknown risk in animals)
藥物相互作用
- Aminoglycosides (gentamicin, amikacin) · Increased risk for nephrotoxicity
- Anticoagulants (heparin, LMWH, warfarin) · Increased risk for bleeding
- Aspirin · Decreased piroxicam plasma levels and increased likelihood of GI adverse effects (blood loss); do not use concurrently
- Bisphosphonates (alendronate) · May increase risk for GI ulceration
- Cisplatin · May potentiate the renal toxicity of cisplatin
- Corticosteroids · Significantly increased risk for GI adverse effects and ulceration · major
- Furosemide · May reduce the saluretic and diuretic effects of furosemide
- Highly protein-bound drugs (phenytoin, valproic acid, sulfonamides) · Piroxicam is 99% protein-bound and may displace other drugs, increasing their serum levels and duration of action
- Methotrexate · Serious toxicity has occurred when used concomitantly; use with extreme caution
- Other NSAIDs · Increased risk of severe gastric ulceration and GI toxicity · major
- Diuretics · Increased risk of nephrotoxicity and renal papillary necrosis · moderate
- Aminoglycosides · Increased risk of nephrotoxicity · moderate
監測
- Adverse Effects (particularly GI bleeding: melena, hematemesis, pale mucous membranes)
- Liver function tests (occasionally with chronic use)
- Renal function tests (occasionally with chronic use)
- Renal function (BUN, Creatinine, SDMA, Urinalysis)
- Liver enzymes
- Clinical signs of GI ulceration (vomiting, melena, anorexia)
- Hydration status
- Skin integrity (especially in cats)
過量
Overdosage can lead to severe **gastrointestinal (ulceration, perforation)** and **renal (papillary necrosis, failure)** effects. Dogs may be more sensitive to the ulcerative effects than humans. **Treatment:** * Decontamination with emetics and/or activated charcoal if recent. * Gastrointestinal protectants (e.g., misoprostol, omeprazole, sucralfate) are strongly warranted. * Fluid diuresis should be considered to protect renal function. * Monitor carefully and provide supportive care.
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