右雷佐生
**右雷佐生 (Dexrazoxane)** 是一種細胞內鐵蟲合劑和化學保護劑，主要用於獸醫腫瘤學。 * **心臟保護**：用於減輕舉蒳環類藥物（如多柔比星）相關的累積性、劑量依賴性心臟毒性，適用於出現毒性跡象、患有心臟疾病或已達到最大累積劑量的患者。 * **外滲處理**：作為重要的解毒劑，用於治療因意外血管外注射（外滲）多柔比星所引起的嚴重組織壞死。 **臨床要點**： * 雖然在心臟保護方面非常有效，但其價格昂貴，許多飼主可能無法負擔。 * 理論上並且在人類醫學中有證據顯示，右雷佐生可能會部分保護癌細胞，從而降低化療方案的抗腫瘤療效。
作用機制: Dexrazoxane is a cyclic derivative of EDTA that readily penetrates cell membranes. * Once intracellular, it is **hydrolyzed** into an active ring-opened chelating metabolite. * **Active Metabolite** → **Chelates intracellular iron** → Prevents the formation of the highly reactive **anthracycline-iron complex**. * This prevents the generation of destructive superoxide free radicals → **Protects the myocardium** from oxidative stress and irreversible anthracycline-induced cardiomyopathy. * *Mechanistic Note*: It also acts as a reversible inhibitor of **Topoisomerase II**, which is believed to contribute to its protective effects against severe tissue necrosis during extravasation injuries.
各物種劑量
- Treatment of anthracycline (doxorubicin, epirubicin, etc.) extravasation · 1000 mg/m2 · IV · within 6 hours and again on day 2. Infuse 500 mg/m2 on day 3 · 3 days · Terminate doxorubicin infusion immediately, and infuse intravenously in a separate infusion. Acute surgical evaluation is performed. Dosage recommendations are for human patients, but may apply to veterinary patients.
- Treatment of anthracycline extravasation · 10 times the doxorubicin dose · IV · within 3 hours and again at 24 and 48 hours after extravasation · 48 hours · Anecdotally; significantly reduces local tissue injury.
- Prevention of doxorubicin-induced cardiomyopathy · 10:1 ratio (e.g., 300 mg/m2 of dexrazoxane to 30 mg/m2 doxorubicin) · IV · starting 30 minutes of, and prior to the doxorubicin dose · Given as slow IV bolus (as a short, IV bolus).
- Prevention of doxorubicin-induced cardiomyopathy · 10:1 ratio (e.g., 300 mg/m2 of dexrazoxane to 30 mg/m2 doxorubicin) · IV · starting 30 minutes before doxorubicin is administered · Given as slow IV bolus. Use can be considered in breeds at risk (Shelties, Collies, Australian Shepherds, etc.), dogs exceeding usual cumulative dose cutoff, and cases with preexisting cardiac disease where no effective chemo options exist.
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
- Should not be used unless an anthracycline antineoplastic agent is being used
- Unknown based on monograph, but generally avoid in patients not receiving anthracyclines
不良反應
- Additive myelosuppression
- Potential reduction in efficacy of anthracycline antitumor agents
- Testicular atrophy (observed in dogs)
- Myelosuppression (documented in humans)
- Decreased clinical efficacy of anthracycline antineoplastic agents
藥物相互作用
- Myelosuppressive agents · Additive myelosuppression may occur when used concurrently.
- Anthracycline antineoplastic agents · May decrease the clinical efficacy of the chemotherapy · moderate
監測
- CBC
- Echocardiogram (if used for cardioprotection)
- ECG (if used for cardioprotection)
- Complete blood count (CBC) for myelosuppression
- Cardiac monitoring (ECG, echocardiogram) if used for cardiotoxicity
- Extravasation site for healing or necrosis
過量
Because of the method of administration and drug expense, overdoses are unlikely in veterinary medicine. As there is no known antidote, treatment would be supportive. Potentially, the drug could be removed via hemodialysis.
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。