碘泊酸鈉
碘泊酸鈉是一種口服的放射性不透光有機碘化合物，最初在人類醫學中用作膽囊造影的顯影劑。在獸醫學中，它被重新定位為治療貓甲狀腺機能亢進的**替代性抗甲狀腺藥物**，特別適用於無法耐受第一線藥物（如甲巰咪唑 methimazole 或卡比馬唑 carbimazole）的患貓。 雖然它能有效減輕甲狀腺機能亢進的臨床症狀，但其使用受到以下幾個重要因素的限制： * **短暫的療效：** 貓咪通常在相對較短的時間後會對此藥物產生抗藥性（療效衰退）。 * **取得不易：** 目前沒有商業化的獸醫或人類產品；必須由調劑藥局（compounding pharmacy）特別配製。 * **疾病嚴重度：** 對於患有嚴重甲狀腺機能亢進的貓，其療效通常較差。 > **臨床要點：** 因為碘泊酸鈉不會降低血清 T4 濃度（甚至可能因清除率降低而使其升高），所以治療監測必須依賴臨床症狀和血清 **T3 濃度**。
作用機制: Ipodate acts via a completely different mechanism than thioureylene antithyroid drugs (like methimazole). Its primary effects include: * **5'-deiodinase inhibition:** It potently inhibits the enzyme responsible for the peripheral conversion of thyroxine (T4) → the more biologically active triiodothyronine (T3). * **Receptor Blockade:** It may competitively block **T3 receptors** in target tissues, thereby protecting organs such as the heart from the hypertrophic and thyrotoxic effects of hyperthyroidism. * **TSH Interference:** It may block the actions of Thyroid Stimulating Hormone (TSH).
各物種劑量
- Medical treatment of hyperthyroidism in patients who cannot tolerate methimazole and whose owners will not permit surgery or radioiodine therapy · 100-200 mg (total dose; empiric) PO once daily · PO · q24h
- Medical treatment of hyperthyroidism in patients who cannot tolerate methimazole and whose owners will not permit surgery or radioiodine therapy · 50 mg per cat PO twice daily, if 'good' clinical response not obtained, at 2 week intervals may increase dose to 150 mg/day (100 mg AM, 50 mg PM) and then to 200 mg/day (100 mg twice daily) · PO · q12h · Cats with severe hyperthyroidism are less likely to respond.
- For use before surgery · 15 mg/kg PO q12h · PO · q12h
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
- Known hypersensitivity to ipodate or other iodine compounds
- Pregnancy (risk of congenital hypothyroidism in fetuses)
不良反應
- GI distress (nausea, vomiting, diarrhea, cramping, inappetence)
- Transient efficacy (patients may become refractory)
- Drug-induced pemphigus (rare)
- Skin rashes, itching, dizziness, and headache (reported in humans)
藥物相互作用
- Radioactive Iodine (I-131) · Ipodate may interfere with radioactive iodine uptake and therapy. It is recommended to discontinue ipodate at least 2 weeks (preferably 3-4 weeks or more) prior to I-131 treatment.
監測
- Clinical efficacy (heart rate, body weight, resolution of clinical signs)
- Serum T3 levels (Note: T4 levels typically do not decrease and may remain high; T4 is NOT a reliable indicator of efficacy for this specific drug)
過量
No specific information located regarding acute toxicity. Cats have reportedly tolerated daily doses up to 400 mg without severe acute adverse effects.
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。