碘塞羅寧鈉
Liothyronine Sodium
3,5,3'-Tri-iodo-L-thyronine sodium
別名: Cytomel · Triostat · Tertroxin · T3 thyronine sodium · sodium L-triiodothyronine · liothyroninum natricum · sodium liothyronine · l-tri-iodothyronine sodium
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
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Hypothyroidism (unresponsive to T4) | 4-6 micrograms/kg PO q8h | PO | q8h | — | 🌎 NA |
| Hypothyroidism (refractory to T4) | 4-6 μg/kg | PO | q8h | — | 🌍 EU |
- Hypothyroidism (unresponsive to T4): Some dogs may require less frequent dosing. Only indicated when T4 supplementation has failed.
- Hypothyroidism (refractory to T4): Not recommended as first-line therapy due to short half-life.
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Hypothyroidism | 4.4 micrograms/kg PO 2-3 times a day | PO | q8h-q12h | — | 🌎 NA |
| T3 suppression test (diagnostic for hyperthyroidism) | 25 μg | PO | q8h | 7 doses total | 🌍 EU |
- T3 suppression test (diagnostic for hyperthyroidism): Administer 7 doses, then measure T4 and T3 on the morning of the 3rd day, 2-4 hours after the 7th dose.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
概覽
碘塞羅寧鈉（Liothyronine sodium）是T3（三碘甲狀腺原氨酸）的合成形式，即甲狀腺激素的活性細胞形式。
雖然左旋甲狀腺素（T4）是甲狀腺機能低下的標準第一線治療藥物，但碘塞羅寧保留用於對T4補充無反應的特定病例。這種無反應可能是由於胃腸道對T4的吸收不良，或理論上T4經脫碘酶轉化為T3的周邊轉化過程存在缺陷。
臨床要點：
- 與左旋甲狀腺素相比，碘塞羅寧的作用時間和半衰期短得多，因此需要更頻繁地給藥（通常為一天三次）。
- 不建議將其用於初始治療，因為它只能使血清T3濃度正常化，而T4水平仍然很低，這會破壞正常的下丘腦-垂體-甲狀腺反饋軸。
- 因為它繞過了身體自然的調節轉化步驟（T4 → T3），病患發生醫源性甲狀腺毒症的風險較高。
作用機轉
Thyroid hormones act primarily at the cellular level to regulate metabolism.
- Mechanism: T3 enters the cell and binds to nuclear thyroid hormone receptors (TRs) → the receptor-hormone complex binds to DNA → stimulates or inhibits the transcription of specific mRNA → alters protein synthesis.
- Physiologic Effects: Increases the metabolic rate of tissues, enhances oxygen consumption, increases body temperature, stimulates gluconeogenesis, and promotes the mobilization and utilization of glycogen stores.
- Cardiovascular Effects: Increases heart rate, cardiac output, and blood volume by upregulating beta-adrenergic receptors.
- Development: Crucial for the adequate development of the central nervous system and skeletal growth.
安全性與警告
禁忌症
- Acute myocardial infarction
- Thyrotoxicosis
- Untreated adrenal insufficiency (Addison's disease)
不良反應
- Tachycardia
- Polyphagia
- Polyuria/Polydipsia (PU/PD)
- Excitability
- Excessive panting
- Apathy or listlessness (seen in about 10% of cats)
- Nervousness/Anxiety
- Weight loss
注意事項
Use with extreme caution and at a lower initial dosage in patients with concurrent hypoadrenocorticism (must be treated first), cardiac disease, diabetes mellitus, or in elderly patients. Combination products containing both T3 and T4 should generally be avoided due to the risk of iatrogenic thyrotoxicosis.
藥物交互作用
Increased risk for CNS stimulation and cardiac arrhythmias.
Thyroid hormones may increase the requirements for insulin or oral antidiabetic agents.
May reduce liothyronine absorption; separate doses by at least 4 hours.
Thyroid hormones can potentiate the cardiovascular effects of sympathomimetics.
Thyroid hormones increase the catabolism of vitamin K-dependent clotting factors, potentially increasing anticoagulation effects.
Potential for reduced digoxin levels and decreased therapeutic effect.
Concurrent use may cause tachycardia and hypertension.
Increased risk of cardiac arrhythmias and coronary insufficiency
May alter glucose control, requiring dosage adjustments
監測
- Serum T3 levels (draw just prior to dosing and 2-4 hours post-pill)
- Clinical signs of hyperthyroidism/thyrotoxicosis
- Note: Serum T4 levels will remain low during therapy
- Heart rate and rhythm
藥物動力學
半衰期
吸收
Nearly completely absorbed in dogs after oral administration. Unlike levothyroxine, absorption is not significantly affected by stomach contents or intestinal flora changes.
分佈
Widely distributed to peripheral tissues. Highly protein-bound in plasma.
代謝
Metabolized primarily in the liver and peripheral tissues via deiodination.
排除
Excreted primarily via feces and urine.
過量
Chronic Overdosage: Produces signs of iatrogenic hyperthyroidism, including tachycardia, polyphagia, PU/PD, excitability, nervousness, and excessive panting. Some cats (approx. 10%) may exhibit 'apathetic' hyperthyroidism (listlessness, anorexia). Treatment: Reduce dosage or temporarily withhold until signs subside.
Acute Massive Overdosage: Can produce signs resembling a thyroid storm.
- Treatment: If oral ingestion is recent, reduce absorption using standard protocols (emetics, gastric lavage, activated charcoal, cathartics) unless contraindicated by the patient's clinical status.
- Supportive Care: Oxygen, artificial ventilation, beta-blockers (e.g., propranolol) for tachycardia/arrhythmias, IV fluids, dextrose, and antipyretic agents as needed.
可用產品
劑型
- Injection
- 20 μg tablets
人用標示
- Liothyronine Sodium Tablets: 5 mcg, 25 mcg & 50 mcg (Cytomel, generic)
- Liothyronine Sodium Injection Solution: 10 micrograms/mL in 1 mL vials (Triostat, generic)
- Tertroxin 20 μg tablets
- Cytomel tablets
各地核准狀態
POM (Prescription Only Medicine)
POM (Prescription Only Medicine)
暫無法規資料: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Tablets should be stored at room temperature (15-30°C) in tight containers. The injection should be stored refrigerated (2-8°C).
飼主須知
重要提示： 請務必完全按照獸醫的指示給予此藥物。未經諮詢獸醫，請勿自行更改劑量或停藥。
- 藥物用途： 這是一種合成甲狀腺激素，用於在標準治療無效時治療甲狀腺機能低下。
- 給藥時間表： 因為它在體內的作用時間不長，通常需要每天給藥2到3次。按時給藥非常重要。
- 注意事項： 如果您發現劑量可能過高的跡象，請聯繫您的獸醫。這些跡象包括過度喘氣、來回踱步、神經質、口渴和排尿增加、食慾大增或心跳過快。在貓咪身上，請注意是否有異常的嗜睡或食慾不振。
- 回診追蹤： 您的寵物需要定期進行血液檢查以確保劑量正確。抽血時間與給藥時間的間隔非常重要，請仔細遵循診所的指示。
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