雙氫速甾醇
Dihydrotachysterol
別名: DHT · Hytakerol · AT 10 · Atiten · Dihydral · Dygratyl · Tachyrol · Tachystin · dichysterol · dihydrotachysterol2
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
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。
各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Hypocalcemia secondary to hypoparathyroidism | Initially give 0.03 mg/kg PO for several days or until effect is demonstrated, then give 0.02 mg/kg for 2 days, then 0.01 mg/kg per day. | PO | q24h | — | 🌎 NA |
- Hypocalcemia secondary to hypoparathyroidism: Pet should remain hospitalized until serum calcium concentration remains stable between 8-9.5 mg/dL. Recheck serum calcium on a weekly basis during early stages of treatment; recheck every 2-3 months long-term. Some dogs and cats that appear to be resistant to treatment on tablets or capsules may respond to the liquid form.
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Hypocalcemia secondary to hypoparathyroidism | Initially give 0.03 mg/kg PO for several days or until effect is demonstrated, then give 0.02 mg/kg for 2 days, then 0.01 mg/kg per day. | PO | q24h | — | 🌎 NA |
| Chronic hypocalcemia with oral calcium tx | Initially: 0.02-0.03 mg/kg/day PO. Maintenance: 0.01-0.02 mg/kg PO q24-48h. | PO | q24-48h | — | 🌎 NA |
- Hypocalcemia secondary to hypoparathyroidism: Pet should remain hospitalized until serum calcium concentration remains stable between 8-9.5 mg/dL. Recheck serum calcium on a weekly basis during early stages of treatment; recheck every 2-3 months long-term. Some dogs and cats that appear to be resistant to treatment on tablets or capsules may respond to the liquid form.
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。
概覽
雙氫速甾醇 (DHT) 是一種合成的脂溶性維生素D類似物，在獸醫學中主要用於治療因甲狀旁腺機能減退或嚴重腎臟疾病引起的低血鈣症。
儘管具有歷史意義，但由於商業供應問題以及骨化三醇 (calcitriol) 具有更有利的藥代動力學特徵（起效更快且作用時間更短，這使得處理意外的高血鈣症更加容易），其臨床應用已在很大程度上被骨化三醇所取代。
關鍵臨床要點：
- 起效時間：比麥角鈣化醇 (維生素D2) 快，但比骨化三醇慢。
- 繞過腎臟活化：與膽鈣化醇不同，DHT 不需要腎臟中的 1-α-羥化酶即可活化，因此對患有嚴重腎衰竭的病患有效。
- 毒性風險：由於其作用可能需要 1 到 3 週才能消退，醫源性高血鈣症是一個顯著的風險，需要嚴密監測。
作用機制
Dihydrotachysterol acts as a synthetic analog of 1,25-dihydroxyvitamin D. Its mechanism of action involves several key steps:
- Hepatic Activation: DHT is absorbed from the GI tract and transported to the liver, where it undergoes hydroxylation by hepatic 25-hydroxylase → 25-hydroxydihydrotachysterol (the active metabolite).
- Receptor Binding: The active metabolite binds to Vitamin D Receptors (VDR) in target tissues (primarily intestine, bone, and kidneys).
- Calcium Homeostasis:
- Intestine: Stimulates the synthesis of calcium-binding proteins (e.g., calbindin) → significantly enhances dietary calcium and phosphorus absorption.
- Bone: Works synergistically with parathyroid hormone (PTH) to promote the accretion and resorption of minerals, mobilizing calcium into the extracellular fluid.
- Kidneys: Promotes the reabsorption of calcium by the renal tubules.
Clinical Pearl: Because the active form of DHT is structurally similar to 1,25-dihydroxyvitamin D, it effectively bypasses the need for renal 1-alpha-hydroxylase, an enzyme often deficient in chronic kidney disease.
安全性與警告
禁忌症
- Pre-existing hypercalcemia
- Vitamin D toxicity
- Malabsorption syndromes
- Abnormal sensitivity to the effects of vitamin D
不良反應
- Hypercalcemia (manifesting as polydipsia, polyuria, anorexia, vomiting, lethargy)
- Nephrocalcinosis (soft tissue mineralization)
- Hyperphosphatemia
注意事項
Important Warnings
- Hyperphosphatemia: Use with extreme caution. Many clinicians consider hyperphosphatemia or a combined calcium/phosphorus product of >70 mg/dL to be an absolute contraindication due to the risk of metastatic soft tissue mineralization (nephrocalcinosis).
- Renal Dysfunction: Use with extreme caution when receiving the drug for non-renal indications.
- Pregnancy: FDA Category C. Hypervitaminosis D has caused fetal abnormalities in various species. Weigh risks vs. benefits.
- Nursing: Vitamin D is excreted in breast milk in limited amounts; use with caution.
- Laboratory Interference: Serum cholesterol levels may be falsely elevated by vitamin D analogs when using the Zlatkis-Zak reaction.
藥物相互作用
Use with vitamin D analogs may induce severe hypercalcemia.
Can nullify the calcium-elevating effects of vitamin D analogs.
Patients are highly sensitive to the arrhythmogenic effects of hypercalcemia; intensified monitoring is required.
Patients are sensitive to the effects of hypercalcemia; intensified monitoring is required.
May reduce the amount of DHT absorbed from the GI tract.
May reduce the amount of DHT absorbed from the GI tract.
May reduce the amount of DHT absorbed from the GI tract.
May induce hepatic enzyme systems and increase the metabolism of Vitamin D analogs, thus decreasing their activity.
May induce hepatic enzyme systems and increase the metabolism of Vitamin D analogs, thus decreasing their activity.
May induce hepatic enzyme systems and increase the metabolism of Vitamin D analogs, thus decreasing their activity.
May cause hypercalcemia when given in conjunction with Vitamin D analogs.
監測
- Serum calcium levels (closely/twice daily during initial treatment; at least 2-4 times yearly during maintenance)
- Serum phosphorus levels (particularly in renal failure patients)
- Calcium-phosphorus product (Ca x P)
藥物動力學
吸收
Readily absorbed from the small intestine if fat absorption is normal. Bile is required for adequate absorption; patients with steatorrhea, liver, or biliary disease will have diminished absorption. Liquid dosage forms may have better bioavailability than tablets/capsules in some animals.
分佈
Widely distributed and highly protein-bound in plasma.
代謝
Hydroxylated in the liver to 25-hydroxy-dihydrotachysterol, the active form of the drug. Does not require parathormone activation in the kidneys.
排除
Excreted primarily via bile and feces. Offloads relatively rapidly compared to some other forms of vitamin D, with effects dissipating in 1-3 weeks.
過量
Acute Toxicity
Acute ingestions should be managed using established protocols for GI decontamination. Orally administered mineral oil may reduce absorption and enhance fecal elimination.
Chronic Toxicity (Hypercalcemia)
Hypercalcemia secondary to chronic dosing is a serious complication.
- Discontinue Therapy: Immediately stop DHT and any exogenous calcium supplementation.
- Severe Hypercalcemia Management: Administer furosemide, calcium-free IV fluids (e.g., 0.9% normal saline) to promote diuresis, urine acidification, and corticosteroids (which decrease intestinal calcium absorption and increase renal excretion).
- Monitoring: Because of the long duration of action of DHT (usually one week and potentially up to 3 weeks), hypercalcemia may persist for an extended period.
- Re-initiation: Restart DHT/calcium therapy at a reduced dosage with diligent monitoring only when serum calcium levels return to the normal range.
可用產品
劑型
- Tablets (compounded)
- Capsules (compounded)
- Oral liquid/concentrate (compounded)
獸醫用
- None commercially available (must be compounded)
人用標示
- None commercially available (must be compounded)
各地核准狀態
暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Store at room temperature (15-30°C). Capsules or tablets should be stored in well-closed, light-resistant containers. Oral concentrate should be stored in tight, light-resistant containers.
飼主須知
寵物主人重要須知
雙氫速甾醇 (DHT) 是一種幫助您的寵物身體吸收和維持正常鈣水平的藥物，通常是因為牠們的甲狀旁腺或腎臟功能不全。
- 嚴格給藥：請完全按照處方給藥。未經獸醫明確指示，絕對不要改變劑量或給予額外的鈣補充劑。即使是微小的改變也可能導致血鈣水平發生危險的波動。
- 高血鈣的徵兆：密切注意寵物是否出現口渴增加（喝更多水）、排尿增加、食慾不振、嘔吐或嚴重嗜睡。如果您注意到這些跡象，請立即聯繫您的獸醫。
- 低血鈣的徵兆：如果劑量太低，您的寵物可能會出現低血鈣的跡象，包括肌肉顫抖、面部抽搐、僵硬、虛弱、行走不協調（共濟失調）、行為改變或癲癇發作。
- 頻繁的血液檢查：您的寵物將需要頻繁的血液檢查，特別是在開始服藥時，以確保牠們的鈣水平處於安全範圍。這對牠們的安全是強制性的。
- 給藥方式：如果您的寵物對藥丸反應不佳，獸醫可能會將其改為液體形式，有時液體的吸收效果更好。
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