阿法沙龍
Alfaxalone
3-alpha-hydroxy-5-alpha-pregnane-11,20-dione
別名: Alfaxan-CD RTU · Alfaxan Multidose · alfaksaloni · alfaxalona · alfaxalonum · alphaxalone · GR-2/234
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
經審核的 v13 劑量證據
經審核的非計算證據經審核的非計算證據 (10)
僅供證據參考，不會自動計算
Crocodilians/induction, but unpredictable results
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 3 mg/kg IV252. Species/Comments: Crocodilians/induction, but unpredictable results.
僅供證據參考，不會自動計算
Lizards, chelonians/induction, 35–40 min; duration, 15–35 min; good muscle relaxation; variable results
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 15 mg/kg IM229. Species/Comments: Lizards, chelonians/induction, 35–40 min; duration, 15–35 min; good muscle relaxation; variable results.
僅供證據參考，不會自動計算
Most species/good muscle relaxation; variable results; drug requires more evaluation; may have violent recovery;198don’t use within 10 days of DMSO treatment
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 6–9 mg/kg IV, or 9–15 mg/kg IM182. Species/Comments: Most species/good muscle relaxation; variable results; drug requires more evaluation; may have violent recovery;198don’t use within 10 days of DMSO treatment.
僅供證據參考，不會自動計算
Horsfield’s tortoises (males only)/light to moderate sedation with no to minimal analgesia; red-eared slider turtles/light sedation of short duration; PD turtles administered 10 mg/kg at low temperature more relaxed than warm, and turtles administered 20 mg/kg at warm temperature were most relaxed
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 10–20 mg/kg IM113,164,300. Species/Comments: Horsfield’s tortoises (males only)/light to moderate sedation with no to minimal analgesia; red-eared slider turtles/light sedation of short duration; PD turtles administered 10 mg/kg at low temperature more relaxed than warm, and turtles administered 20 mg/kg at warm temperature were most relaxed.
僅供證據參考，不會自動計算
Turtles, tortoises/induction
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 5 mg/kg IV170. Species/Comments: Turtles, tortoises/induction.
僅供證據參考，不會自動計算
Most species
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 6–15 mg/kg IM, IV298. Species/Comments: Most species.
僅供證據參考，不會自動計算
Snakes, lizards/induction; not effective for blotched blue-tongued skinks
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 9 mg/kg IV290. Species/Comments: Snakes, lizards/induction; not effective for blotched blue-tongued skinks.
僅供證據參考，不會自動計算
Red-eared slider turtles, Eastern painted turtles, yellow-spotted Amazon river turtles, other undocumented turtle species/anesthetic induction
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 20 mg/kg IM141. Species/Comments: Red-eared slider turtles, Eastern painted turtles, yellow-spotted Amazon river turtles, other undocumented turtle species/anesthetic induction.
僅供證據參考，不會自動計算
Chelonians (red-eared sliders)/surgical anesthesia with good relaxation
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 24 mg/kg ICe111. Species/Comments: Chelonians (red-eared sliders)/surgical anesthesia with good relaxation.
僅供證據參考，不會自動計算
Bearded dragons/effective for induction of anesthesia; respiratory depression noted
TABLE 127.5. Agent: Alfaxalone(Alfaxan, Jurox). Dosage: 12 mg/kg IV262. Species/Comments: Bearded dragons/effective for induction of anesthesia; respiratory depression noted.
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
阿法沙龍 (Alfaxalone) 是一種神經活性類固醇分子，作為一種速效中樞神經系統抑制劑和全身麻醉藥。它主要用於獸醫病患的麻醉誘導與維持。
臨床要點與藥理特性：
- 配方演進： 現代配方 (Alfaxan®) 使用 2-羥丙基-β-環糊精 (HPCD) 作為助溶劑。這比歷史產品 (Saffan®) 有了顯著改進，舊產品含有聚氧乙烯蓖麻油 (Cremophor EL)，會引起嚴重的組織胺釋放和過敏反應（特別是在貓）。
- 心肺影響： 雖然通常被認為具有較寬的安全範圍，但阿法沙龍會引起劑量依賴性的呼吸抑制和誘導後呼吸中止，特別是如果靜脈注射過快時。心血管參數通常維持良好，儘管可能會出現代償性心搏過速。
- 鎮痛作用： 阿法沙龍幾乎沒有鎮痛效果。對於疼痛性操作，必須結合適當的純鎮痛藥（例如鴉片類藥物）。
- 恢復： 由於其半衰期短且無蓄積性，恢復通常快速且平穩，但如果受到刺激或術前給藥/鎮痛不足，病患可能會經歷精神運動性興奮（划水動作、發聲、抽搐）。
作用機轉
Alfaxalone exerts its anesthetic effects by interacting with GABA_A (gamma-aminobutyric acid type A) receptors in the central nervous system.
- Mechanism: It binds to specific transmembrane domains on the GABA_A receptor complex.
- Pathway: Binding → Enhances the binding of the inhibitory neurotransmitter GABA to the receptor → Increases the frequency and duration of chloride (Cl⁻) ion channel opening → Influx of chloride ions into the neuron → Hyperpolarization of the postsynaptic cell membrane → Inhibition of neural action potential transmission → Dose-dependent CNS depression (ranging from sedation to general anesthesia).
安全性與警告
禁忌症
- Concurrent use with other injectable general anesthetic agents (e.g., propofol, thiopental)
- Situations where endotracheal intubation, positive pressure ventilation, and oxygen support are unavailable
- Animals less than 12 weeks of age (safety not established)
不良反應
- Respiratory depression
- Post-induction apnea
- Hypotension (dose-dependent)
- Cardiac arrhythmias (primarily secondary to hypoxemia/hypercapnia)
- Psychomotor excitement during recovery (especially if unstimulated or lacking premedication)
注意事項
Critical Warning: Post-induction apnea is common (up to 44% in dogs, 19% in cats). Alfaxalone should only be used when endotracheal intubation and oxygen supplementation/ventilation are immediately available.
- Administration Rate: Give slowly IV (over 60 seconds or titrated to effect) to minimize the risk of severe apnea.
- Hepatic Dysfunction: Use with caution; lower dosages or increased dosing intervals may be required as the drug undergoes extensive hepatic metabolism.
- Recovery Environment: Keep patients in a quiet, unstimulating environment during recovery to minimize psychomotor excitement. Avoid handling unless necessary.
- Analgesia: Always provide concurrent appropriate pain control, as alfaxalone offers no analgesia.
藥物交互作用
Potentiates the CNS and respiratory depressant effects. Significantly reduces the required induction and maintenance doses of alfaxalone.
Should not be used concurrently according to the manufacturer label.
Should not be used concurrently according to the manufacturer label.
Increased risk of severe CNS and respiratory depression
Synergistic CNS depression; significantly reduces the required induction dose of alfaxalone
Synergistic CNS depression; reduces the required induction dose of alfaxalone.
Profound synergy; significantly reduces alfaxalone dose requirements and may exacerbate cardiovascular and respiratory depression.
Enhanced sedation and increased risk of hypotension.
Synergistic CNS depression; significantly reduces the required induction dose of alfaxalone.
Synergistic CNS depression; reduces alfaxalone dose requirements.
監測
- Level of anesthesia / CNS depression (jaw tone, palpebral reflex)
- Respiratory rate, rhythm, and depth (capnography and pulse oximetry highly recommended due to apnea risk)
- Cardiovascular status (heart rate, ECG rhythm, blood pressure)
- Body temperature (monitor for hypothermia during anesthesia)
藥物動力學
半衰期
吸收
Rapid onset following intravenous administration. Well absorbed following deep intramuscular injection in cats.
分佈
Widely distributed. Volume of distribution (Vd) in dogs is approximately 2.5 L/kg; in cats, approximately 2 L/kg.
代謝
Undergoes extensive hepatic metabolism via Phase I (cytochrome P450 dependent) and Phase II (conjugation dependent) pathways. Cats form alfaxalone sulfate and alfaxalone glucuronide; dogs form only alfaxalone glucuronide.
排除
Metabolites are eliminated via hepatic/fecal and renal routes. Clearance in dogs is ~54 mL/kg/min. Clearance in cats is dose-dependent (25.1 mL/kg/min at 5 mg/kg; 14.8 mL/kg/min at 25 mg/kg). No clinically relevant accumulation occurs with multiple doses.
過量
Overdoses up to 25 mg/kg primarily result in severe cardiorespiratory depression.
Clinical Signs of Toxicity:
- Severe hypoventilation and prolonged apnea
- Hypotension
- Cardiac arrhythmias
Treatment:
- Immediate endotracheal intubation and positive pressure ventilation with 100% oxygen.
- Cardiovascular support (IV fluids, vasopressors/inotropes if hypotension is severe).
- Continuous monitoring until the drug is metabolized and cleared.
可用產品
劑型
- 10 mg/mL injection (10 mL and 20 mL vials)
獸醫用
- Alfaxan® 10 mg/mL injection (10 mL and 20 mL vials)
各地核准狀態
Approved for induction and maintenance of anesthesia.
Prescription Only Medicine - Veterinarian.
暫無法規資料: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Store at room temperature (<30°C) and protect from light. Do not freeze. According to the New Zealand label, broached (punctured) vials should preferably be used within 24 hours, but may be stored at 4°C for up to 7 days provided contamination is avoided. Discard if the solution is not clear, colorless, or contains particulate matter.
飼主須知
什麼是阿法沙龍？ 阿法沙龍是一種速效、高度安全的注射型麻醉藥，用於在手術前引導睡眠或為小型手術提供深度鎮靜。
預期情況：
- 作用迅速： 您的寵物在注射後會非常快速且平穩地入睡。
- 監測： 因為它可能會暫時減緩呼吸，您的獸醫團隊會在整個過程中密切監測寵物的呼吸、心跳和血氧濃度。
- 恢復： 手術結束後，寵物通常會很快醒來。然而，在恢復階段，牠們可能對噪音、光線和觸摸很敏感。如果受到驚嚇，牠們可能會抽搐、四肢划水或發出聲音。
- 術後護理： 獸醫人員會讓您的寵物待在安靜、溫暖且昏暗的環境中，直到牠們完全清醒且步伐平穩。寵物出院後，不需要針對此藥物進行特別的居家護理。
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