可辛促素
**可辛促素 (Cosyntropin)** 是一種合成的多肽，可模擬內源性促腎上腺皮質素 (ACTH) 的作用。在獸醫學中主要作為診斷劑使用。 * **主要用途：** 作為 ACTH 凝膠的替代品，用於腎上腺功能測試（ACTH 刺激試驗）。 * **適應症：** 用於診斷腎上腺皮質機能減退症（愛迪生氏症）、醫源性腎上腺皮質機能亢進症（庫興氏症候群），以及監測 mitotane 或 trilostane 治療庫興氏症候群的反應。 * **優勢：** 由於缺乏內源性促皮質素的 C 端部分，其免疫原性顯著較低，對於過去曾對動物來源 ACTH 產生過敏反應的病患更為安全。
作用機制: Cosyntropin acts identically to endogenous ACTH. It binds to **melanocortin type 2 receptors (MC2R)** in the adrenal cortex → stimulates the production of intracellular cAMP → promotes the conversion of cholesterol to pregnenolone → rapidly stimulates the adrenal cortex to secrete **cortisol**, corticosterone, and weak androgens. Because it only contains the first 24 amino acids of natural corticotropin (which has 39), it retains full biological activity but lacks the highly immunogenic C-terminal amino acids (25-39).
各物種劑量
- Tentative diagnosis of Addison's disease · 0.125 mg of cosyntropin IV or IM · IV/IM · Once · Draw baseline cortisol, give dexamethasone SP 2-5 mg/kg, give cosyntropin, draw second sample 45-60 mins later.
- ACTH Stimulation test · 0.125 mg (total dose-125 mcg) IM or IV · IM/IV · Once · Begin test between 8-9 AM; obtain preinjection cortisol level and 30 minutes and 1 hour post.
- Diagnosis of hyperadrenocorticism · 125 micrograms/cat IM or IV · IM/IV · Once · Cortisol measurements before and at 30 and 60 minutes post.
- Low dose ACTH stimulation test · 5 micrograms/kg · IV/IM · Once · Cortisol concentrations peak at 60 minutes post-dose.
- ACTH stimulation test · 5 μg/kg or 125 μg/cat · IV/IM · once · single dose · Cortisol response is less dramatic than in dogs; use feline-specific reference ranges.
- Relative adrenal insufficiency (RIA) evaluation in critically ill horses · 0.1 micrograms/kg · IV/IM · Once · Cortisol will peak after 30 minutes.
- ACTH Stimulation test · 1 mg IV · IV · Once · Administer between 8 and 10 AM; take post ACTH cortisol levels at 2 hours post dose.
- ACTH Stimulation test (Foals) · 0.5 micrograms/kg IV · IV · Once · Peak cortisol levels occur at 30 minutes post dose.
- Tentative diagnosis of Addison's disease · 0.25 mg (250 micrograms) of cosyntropin IV or IM · IV/IM · Once · Draw baseline cortisol, give dexamethasone SP 2-5 mg/kg, give cosyntropin, draw second sample 45-60 mins later.
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 cosyntropin
- No information available
不良反應
- Hypersensitivity reactions (rare, but possible)
- Pain on intramuscular (IM) injection
藥物相互作用
- Hydrocortisone / Cortisone · Cross-reacts with cortisol assays; patients should not receive these on test day (dexamethasone does not interfere).
- Spironolactone · May cause falsely high cortisol values if using a fluorometric analysis.
監測
- Plasma or serum cortisol levels (baseline and post-stimulation)
- Patient monitoring for rare hypersensitivity reactions during the test
- Serum cortisol levels (baseline/pre-ACTH and post-ACTH, typically at 1 hour post-injection)
過量
Unlikely to be of clinical consequence if used one-time only for diagnostic purposes.
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