氯吡格雷
**氯吡格雷 (Clopidogrel)** 是一種強效的口服血小板凝集抑制劑（屬於噻吩吡啶類），在獸醫學中廣泛用於預防危險的血栓形成。 - **貓科醫學**：常被用於預防患有潛在心臟病（如肥厚型心肌病）貓咪的**貓主動脈血栓栓塞症 (FATE)**。它也可能透過血管調節作用改善栓塞事件後的骨盆肢體血液循環。 - **犬科醫學**：用於控制與**免疫介導性溶血性貧血 (IMHA)**、蛋白質流失性腸病/腎病 (PLE/PLN) 以及腎上腺皮質機能亢進等疾病相關的高凝血狀態。 **臨床提示**：氯吡格雷的味道非常苦。如果貓咪嚐到藥錠的味道，可能會大量流口水。強烈建議將藥物放入空的明膠膠囊中餵食，以確保服藥順從性。
作用機制: Clopidogrel is a **prodrug** that requires hepatic biotransformation (via **CYP450** enzymes) to its active, highly unstable thiol metabolite. - The active metabolite → binds selectively and **irreversibly** to the **P2Y12** subtype of **ADP-receptors** on the platelet surface. - This blocks **ADP** binding → prevents activation of the **glycoprotein IIb/IIIa** complex. - Without this complex, platelet-fibrinogen binding cannot occur, effectively halting both primary and secondary platelet aggregation. - It also inhibits the release of other pro-aggregation compounds (serotonin, calcium, thromobospondin). Because the binding is irreversible, the platelet is inhibited for its entire lifespan (approximately 7-10 days). Normal coagulation only returns as new platelets are synthesized.
各物種劑量
- As an anti-platelet agent · 1-3 mg/kg PO once daily; if used with aspirin give lower doses (0.5-1 mg/kg PO once daily) · PO · once daily
- Thromboprophylaxis · 1.1-4 mg/kg · PO · q24h · A single loading dose of 4-10 mg/kg p.o. may help achieve therapeutic concentrations more rapidly.
- To prevent thrombus formation · 18.75 mg (practically, 1/4 of a 75 mg tablet) PO once daily · PO · once daily
- To prevent thrombus formation (combination therapy) · 7 mg (total dose) PO once daily in combination with aspirin 40-81 mg (total dose) every 3 days. · PO · once daily · Clinical trials are needed to determine appropriate dosage and indications.
- To prevent thrombus formation · 1-3 mg/kg PO once daily; if used with aspirin give lower doses (0.5-1 mg/kg PO once daily) · PO · once daily
- Thromboprophylaxis · 18.75 mg/cat · PO · q24h · A single loading dose of 4-10 mg/kg p.o. may help achieve therapeutic concentrations more rapidly. Administer in a gelatin capsule to improve compliance due to bitter taste.
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Active pathologic bleeding
- Known hypersensitivity to the drug
不良反應
- Vomiting
- Anorexia
- Bleeding/hemorrhage
- Diarrhea
- Rashes
- Thrombotic thrombocytopenic purpura (TTP) - rare in humans
藥物相互作用
- Aspirin · Increased risk for bleeding; however, many patients take both medications intentionally for dual antiplatelet therapy. · moderate
- Heparin / Low Molecular Weight Heparins (LMWH) · Clopidogrel appears safe to use concurrently with heparin.
- NSAIDs · Increased risk for bleeding; clopidogrel may interfere with NSAID metabolism.
- Phenytoin · Clopidogrel may interfere with phenytoin metabolism.
- Proton Pump Inhibitors (e.g., omeprazole) · May decrease the efficacy of clopidogrel by inhibiting CYP2C19, the enzyme needed to convert clopidogrel to its active metabolite.
- Torsemide · Clopidogrel may interfere with torsemide metabolism.
- Warfarin · Increased risk for bleeding; clopidogrel may interfere with warfarin metabolism.
- Anticoagulants · High risk of bleeding complications · major
監測
- Clinical efficacy (prevention of thromboembolic events)
- Adverse effects (vomiting, anorexia)
- Signs of bleeding (petechiae, ecchymosis, melena, epistaxis)
過量
Limited information is available. Reported lethal oral doses for mice and rats were 1500 mg/kg and 2000 mg/kg, respectively. **Clinical Signs**: Acute toxic signs may include bleeding or vomiting. **Treatment**: Platelet transfusions have been suggested if rapid reversal is required.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。