骨化三醇
Calcitriol
1,25-dihydroxycholecalciferol
別名: Rocaltrol · Calcijex · Active Vitamin D3 · 1,25-dihydroxycholecalciferol · 1-alpha,25 dihydrocholecalciferol · 1,25-DHCC · 1,25-dihidroxyvitamin D3
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 |
|---|---|---|---|---|---|
| To suppress secondary hyperparathyroidism in CRF | 2.5-3.5 nanograms/kg/day PO (Dogs with refractory hyperparathyroidism may require up to 6 nanograms/kg/day). Alternatively, pulsed-dosing: 20 nanograms/kg twice weekly PO at bedtime on an empty stomach. | PO | q24h or twice weekly | Long-term | 🌎 NA |
| Subacute and chronic maintenance treatment of hypocalcemia | Initially, 20-30 nanograms/kg/day PO divided twice a day for 3-4 days, then 5-15 nanograms/kg/day divided twice a day | PO | q12h | Initial 3-4 days, then maintenance | 🌎 NA |
| Long-term maintenance in animals with hypoparathyroidism | 0.03-0.06 micrograms/kg/day | PO | q24h | Long-term | 🌎 NA |
| Primary idiopathic seborrhea (especially in spaniel breeds) | 10 nanograms/kg PO once daily | PO | q24h | — | 🌎 NA |
- To suppress secondary hyperparathyroidism in CRF: Confirm CRF (creatinine >2 mg/dL) and reduce hyperphosphatemia to <6 mg/dL before starting.
- Long-term maintenance in animals with hypoparathyroidism: Combine with oral calcium to reduce vitamin D dose requirements.
- Primary idiopathic seborrhea (especially in spaniel breeds): Give as far away from the main meal as possible.
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| To suppress secondary hyperparathyroidism in CRF | 1.5-3.5 nanograms/kg PO daily given separately from meals (or 2.5-3.5 nanograms/kg PO once daily) | PO | q24h | Long-term | 🌎 NA |
| Long-term maintenance in animals with hypoparathyroidism | 0.03-0.06 micrograms/kg/day | PO | q24h | Long-term | 🌎 NA |
- To suppress secondary hyperparathyroidism in CRF: Remove oil from capsule, dilute in corn oil, then give the appropriate volume.
- Long-term maintenance in animals with hypoparathyroidism: Combine with oral calcium to reduce vitamin D dose requirements.
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
骨化三醇（Calcitriol）是維生素D的活性荷爾蒙形式。在獸醫學中，主要用於治療低血鈣症（通常繼發於副甲狀腺機能低下），以及抑制慢性腎病（CKD）中的繼發性副甲狀腺機能亢進。它也可能對治療某些犬種的原發性特發性皮脂漏有益。
臨床要點： 在健康的動物中，腎臟會產生1-α-羥化酶，將無活性的維生素D轉化為活性形式（骨化三醇）。在慢性腎衰竭中，功能性腎臟質量的喪失導致此酵素缺乏。補充骨化三醇可繞過此代謝缺陷，直接抑制副甲狀腺素（PTH）的合成，從而預防或治療腎性繼發性副甲狀腺機能亢進（腎性骨病）。
作用機制
Calcitriol binds to the intracellular Vitamin D Receptor (VDR) in target tissues (intestine, bone, kidney, and parathyroid gland) to regulate calcium and phosphorus homeostasis.
- Intestine: Upregulates the synthesis of calcium-binding proteins (e.g., calbindin) → significantly enhances the GI absorption of calcium and phosphorus.
- Kidney: Promotes renal tubular reabsorption of calcium.
- Parathyroid Gland: Directly binds to VDRs on the parathyroid gland → inhibits the transcription of the PTH gene, reducing PTH synthesis and secretion.
- Bone: Works synergistically with PTH to stimulate osteoclast activity, mobilizing calcium and phosphorus into the extracellular fluid.
Unlike other forms of vitamin D (like cholecalciferol or ergocalciferol), calcitriol does not require hepatic or renal activation, resulting in a rapid onset of action (approximately 1 day) and a short half-life.
安全性與警告
禁忌症
- Hypercalcemia
- Hyperphosphatemia (Calcium x Phosphorus product > 70)
- Vitamin D toxicity
- Malabsorption syndromes
- Abnormal sensitivity to vitamin D effects
不良反應
- Hypercalcemia
- Hypercalciuria
- Polydipsia
- Polyuria
- Anorexia
- Tissue mineralization (if given with hyperphosphatemia)
注意事項
Use with extreme caution in patients with hyperphosphatemia; calcium and phosphorus levels should be in the low-normal range before beginning treatment to prevent soft tissue mineralization. Use with caution in animals susceptible to calcium oxalate uroliths due to the risk of hypercalciuria. Calcitriol is teratogenic at high doses (FDA Category C). 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 calcitriol may induce hypercalcemia.
Can nullify the 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 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 (baseline, 1 week, then every 2-4 weeks/6 months depending on protocol)
- Serum phosphorus
- Serum creatinine
- Serum PTH levels (especially in cats or refractory cases)
- Clinical efficacy (improved appetite, activity level, slowed progression of disease)
藥物動力學
吸收
Readily absorbed from the GI tract (small intestine) if fat absorption is normal. Bile is required for adequate absorption; patients with steatorrhea, liver, or biliary disease will have diminished absorption.
過量
Overdosage can cause hypercalcemia, hypercalciuria, and hyperphosphatemia.
- Acute Ingestion: Manage using established protocols for GI decontamination. Orally administered mineral oil may reduce absorption and enhance fecal elimination.
- Chronic Overdosage: Hypercalcemia secondary to chronic dosing should be treated by first temporarily discontinuing (not just dose reduction) calcitriol and exogenous calcium therapy.
- Severe Hypercalcemia: May require treatment with furosemide, calcium-free IV fluids (e.g., normal saline), urine acidification, and corticosteroids.
可用產品
劑型
- Oral capsules
- Oral solution
- Injection
- Topical
人用標示
- Calcitriol Oral Capsules: 0.25 micrograms & 0.5 micrograms (Rocaltrol)
- Calcitriol Oral Solution: 1 microgram/mL (Rocaltrol)
- Calcitriol Injection: 1 microgram/mL & 2 micrograms/mL (Calcijex)
- Topical formulations
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
Protect from light. Store in tight, light-resistant containers at room temperature. The injection does not contain preservatives and remaining drug should be discarded after opening the ampule.
飼主須知
骨化三醇是一種強效的維生素D，用於幫助平衡寵物的血鈣濃度或控制腎臟疾病的併發症。由於寵物所需的劑量極小，通常需要由藥局特別調配。
- 給藥時間： 如果使用較低劑量（<3.5 奈克/公斤/天），請與早餐一起餵食。如果使用較高劑量（>5 奈克/公斤/天），請在睡前空腹給藥，以降低血鈣飆高的風險。
- 注意高血鈣症狀： 如果您發現寵物出現口渴增加（多飲）、排尿增加（多尿）或食慾不振，請立即聯繫您的獸醫師。
- 注意低血鈣症狀： 如果是為了治療低血鈣，請觀察是否出現肌肉顫抖、面部抽搐、僵硬、虛弱、走路不穩（共濟失調）、行為改變或癲癇發作。
- 營養補充品： 未經獸醫師明確指示，請勿給您的寵物服用任何市售的鈣片或維生素D補充劑。
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