阿芬太尼
阿芬太尼是一種**強效、短效的合成鴉片類藥物**，屬於苯基哌啶類，結構上與芬太尼相似。 主要特徵包括： * **起效快且作用時間短：** 具高脂溶性，能迅速穿透血腦屏障，非常適合用於短時間的手術或作為連續速率輸注 (CRI)。 * **麻醉輔助劑：** 主要用於提供深度的鎮痛效果，並減少誘導或維持麻醉劑（如丙泊酚、異氟醚）的所需劑量。 * **物種特異性：** 雖然在獸醫學上的使用經驗不如芬太尼豐富，但特別指出在貓的麻醉過程中作為輔助治療非常有用。 * **管制狀態：** 由於具有高度濫用潛力，被列為**第二級管制藥品**。
作用機制: Alfentanil acts primarily as a potent and highly selective agonist at **mu (μ) opioid receptors** in the central nervous system. * **Mechanism:** Binds to pre- and post-synaptic **μ-receptors** → inhibits adenylate cyclase → decreases intracellular cAMP → promotes opening of inward-rectifying potassium channels → hyperpolarization of the neuron. * **Neurotransmitter Inhibition:** Concurrently inhibits voltage-gated calcium channels → decreases the release of excitatory nociceptive neurotransmitters (such as **substance P** and **glutamate**) → profound analgesia and sedation. * **Systemic Effects:** Causes dose-dependent respiratory depression by decreasing the responsiveness of the brainstem respiratory centers to carbon dioxide.
各物種劑量
- As a premed · 5 micrograms/kg alfentanil with 0.3-0.6 mg of atropine · IV · 30 seconds before injecting propofol · Can reduce the dose of propofol needed to induce anesthesia to 2 mg/kg, but apnea may still occur.
- As a constant rate infusion for pain · Loading dose of 0.5-1 micrograms/kg, then a CRI of 0.5-1 micrograms/kg per minute. · IV · CRI
- As an analgesic supplement to anesthesia · 2-5 micrograms/kg · IV · q20 minutes
- For intra-operative analgesia in patients with intracranial disease · 0.2 micrograms/kg/minute · IV · CRI
- Intraoperative analgesia · 0.001-0.005 mg/kg · IV · single bolus · Administer slowly to avoid severe bradycardia
- Intraoperative analgesia · 0.001-0.0025 mg/kg/min · IV · continuous rate infusion · Best method of administration due to short duration of action
- Intraoperative analgesia · 0.001 mg/kg · IV · single bolus · Administer slowly to avoid severe bradycardia
- Intraoperative analgesia · 0.001 mg/kg/min · IV · continuous rate infusion · Best method of administration due to short duration of action
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Patients hypersensitive to opioids
不良反應
- Dose-related respiratory depression
- Bradycardia
- CNS depression
- Dose-related skeletal muscle rigidity
- Asystole (rare)
- Hypercarbia (rare)
- Hypersensitivity reactions (rare)
藥物相互作用
- CYP3A4 Inhibitors (erythromycin, cimetidine, ketoconazole, itraconazole, fluconazole, diltiazem) · May increase the half-life and decrease the clearance of alfentanil leading to prolonged effect and an increased risk of respiratory depression
- Beta-blockers · May produce bradycardia or hypotension if used concurrently with alfentanil
- Other anesthetic agents · May produce bradycardia or hypotension; respiratory or CNS depression may be exacerbated
- Inhaled anaesthetics · Reduces the dose requirements of concurrently administered anaesthetics by at least 50% · major
- Monoamine oxidase inhibitors (MAOIs) · Risk of serotonin toxicity · major
監測
- Anesthetic and/or analgesic efficacy
- Cardiac rate and rhythm
- Respiratory rate and depth
- Pulse oximetry or other methods to measure blood oxygenation
過量
### Signs of Toxicity * **Severe IV Overdose:** Circulatory collapse, pulmonary edema, seizures, cardiac arrest, and death. * **Less Severe Overdose:** CNS and respiratory depression, coma, hypotension, muscle flaccidity, and miosis. ### Treatment * **Supportive Care:** Provide cardiovascular and respiratory support (e.g., mechanical ventilation, IV fluids) as necessary. * **Antidote:** Administration of an opiate antagonist such as **naloxone**. Although alfentanil has a relatively rapid half-life, multiple doses of naloxone may be necessary. > **Measurement Precaution:** Because of the drug's extreme potency, the use of a tuberculin syringe to measure dosages less than 1 mL, along with a dosage calculation and measurement double-check system, is strongly recommended.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。