異克舒普林
Isoxsuprine 是一種**周邊血管擴張劑**，在獸醫學中主要用於治療馬的**舟狀骨病 (navicular disease)**，但由於其口服生物利用度差，近期的研究對其口服療效提出質疑。 * **馬科應用**：歷史上用於改善馬蹄及舟狀骨滑車的血液循環。也有傳聞用作安胎劑。 * **犬科應用**：傳聞可用於治療**類雷諾氏症候群**（週期性指端發紺、甲彎曲）。 * **鳥類應用**：可能改善微循環。 **臨床要點**：由於顯著的首過代謝效應，馬匹口服給藥通常無法達到可測量的血漿濃度，導致許多現代獸醫對其在舟狀骨症候群的臨床實用性產生質疑，轉而傾向使用如 pentoxifylline 等其他血液流變學藥物。
作用機制: Isoxsuprine acts as a **beta-adrenergic agonist** (specifically **beta-2 receptors**), though its vasodilatory effects may also stem from direct smooth muscle relaxation independent of beta-receptors. * **Vasodilation**: Stimulates **beta-2 receptors** → increases intracellular **cAMP** → decreases intracellular calcium → **vascular smooth muscle relaxation** (primarily in skeletal muscle). * **Uterine Relaxation**: Relaxes uterine smooth muscle, acting as a tocolytic agent. * **Hemorrheologic Effects**: At high doses, it can decrease blood viscosity and reduce platelet aggregation. * **Cardiac Effects**: May exhibit positive inotropic and chronotropic effects on the heart via **beta-1 receptor** stimulation. * **Analgesia**: Does not appear to possess significant analgesic properties in horses.
各物種劑量
- Treatment of orthopedic conditions, such as navicular disease (For long break-over if therapeutic shoeing does not correct) · 1.2 mg/kg PO q8h for 3 weeks. The dose is decreased as soundness improves, to 1.2 mg/kg PO once daily for 6 weeks, then every other day until heel first landing occurs. · PO · q8h initially · 3 weeks initially, then tapered · Phenylbutazone is added if lameness is greater than grade II on a scale of I-V, or until recheck occurs. The drug is classified as a 'blocking' agent by the AHSA.
- Treatment of orthopedic conditions, such as navicular disease (To increase the circulation to the podotrochlea) · 0.6-1.2 mg/kg twice daily until sound, then decreased to once daily for 2 weeks then further decreased to every other day. · PO · twice daily initially · Until sound, then tapered
- Treatment of orthopedic conditions · 0.6-2 mg/kg PO q12h · PO · q12h
- As a tocolytic agent · 0.4-0.6 mg/kg IM or PO twice daily · IM or PO · twice daily · Efficacy is unproven and oral bioavailability appears highly variable.
- Treatment of 'Raynaud-like' disease · 1 mg/kg/day PO · PO · daily
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
- Immediately post-partum
- Presence of arterial bleeding
不良反應
- CNS stimulation (uneasiness, hyperexcitability, nose-rubbing)
- Sweating
- Hypotension
- Tachycardia
- Gastrointestinal disturbances
監測
- Clinical efficacy (improvement in lameness or digital circulation)
- Adverse effects (tachycardia, GI disturbances, CNS stimulation)
過量
Serious toxicity is unlikely in horses after an inadvertent oral overdose due to poor bioavailability. * **Clinical Signs**: CNS stimulation (uneasiness, hyperexcitability, nose-rubbing), sweating, hypotension, tachycardia, and GI disturbances. * **Treatment**: Provide supportive care. Treat CNS hyperexcitability with **diazepam**, and hypotension with **intravenous fluids**.
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。