コシントロピン
**コシントロピン**は、内因性副腎皮質刺激ホルモン（ACTH）の作用を模倣する合成ポリペプチドです。主に獣医学において診断薬として使用されます。 * **主な用途:** 副腎機能検査（ACTH刺激試験）におけるACTHゲルの代替薬。 * **適応症:** 副腎皮質機能低下症（アジソン病）、医原性副腎皮質機能亢進症（クッシング症候群）の診断、およびミトタンやトリロスタン治療の反応モニタリング。 * **利点:** 内因性コルチコトロピンのC末端部分を欠いているため、免疫原性が著しく低く、過去に動物由来のACTHにアレルギー反応を示した患者に対してより安全です。
作用機序: 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).
動物種別の用量
- 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.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Known hypersensitivity to cosyntropin
- No information available
有害事象
- Hypersensitivity reactions (rare, but possible)
- Pain on intramuscular (IM) injection
薬物相互作用
- 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.
モニタリング
- 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)
過量投与
Unlikely to be of clinical consequence if used one-time only for diagnostic purposes.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。