氟馬西尼
氟馬西尼是一種高度專一的**苯二氮平類拮抗劑**，在獸醫學中主要用於逆轉因治療或意外過量引起的苯二氮平類藥物（如地西泮、咪達唑侖、唑拉西泮）的中樞神經系統（CNS）抑制作用。 **主要臨床應用：** * **逆轉鎮靜/麻醉：** 快速逆轉苯二氮平類藥物引起的鎮靜作用。 * **肝性腦病：** 可作為輔助療法，透過拮抗內源性苯二氮平類物質，暫時改善嚴重肝衰竭病患的神經功能。 * **毒性/過量：** 有效治療苯二氮平類藥物及某些非苯二氮平類安眠藥（如 Zolpidem/Ambien®）的過量。 > **臨床要點：** 當用於逆轉替來他明-唑拉西泮（Telazol®）麻醉組合時，氟馬西尼能成功逆轉唑拉西泮的成分（鎮痛、姿勢、聽覺效應），但**不能**逆轉替來他明（一種解離性麻醉劑）。這可能導致甦醒過程不平穩，出現殘留的解離效應（如肌肉僵硬、焦躁不安），而缺乏苯二氮平類的平緩作用。
作用機制: Flumazenil acts as a competitive antagonist at the **benzodiazepine recognition site** on the **GABA-A/benzodiazepine receptor complex** in the central nervous system. **Mechanism Pathway:** Flumazenil binds to the receptor → competitively displaces benzodiazepine molecules → prevents the allosteric enhancement of **GABA** → prevents the opening of **chloride (Cl-) channels** → reverses GABAergic inhibitory effects (sedation, amnesia, muscle relaxation).
各物種劑量
- As an antagonist for benzodiazepines · 0.01 mg/kg IV; may need to be repeated as half-life is only about an hour. May also be administered intratracheally in an emergency. · IV, Intratracheal · PRN · May need to be repeated due to short half-life.
- Reversal of benzodiazepine sedation and respiratory depression · 0.01-0.1 mg/kg · IV · prn (can be repeated if marked respiratory depression reoccurs) · As needed · Start at the low end of the dose range. It takes 6-10 minutes for flumazenil to reach peak effects after IV administration.
- As an antagonist for benzodiazepines · 0.01 mg/kg IV · IV · once
- As an antagonist for benzodiazepines · 0.01 mg/kg IV; may need to be repeated as half-life is only about an hour. May also be administered intratracheally in an emergency. · IV, Intratracheal · PRN · May need to be repeated due to short half-life.
- For adjunctive therapy to improve neurologic function in dogs with severe hepatic encephalopathy · 0.02 mg/kg IV (one time) · IV · once
- For adjunctive therapy to improve neurologic function in dogs with severe hepatic encephalopathy · 0.02 mg/kg IV; if animal responds, safe to use repeatedly · IV · PRN
- Reversal of benzodiazepine sedation and respiratory depression · 0.01-0.1 mg/kg · IV · prn (can be repeated if marked respiratory depression reoccurs) · As needed · Start at the low end of the dose range. It takes 6-10 minutes for flumazenil to reach peak effects after IV administration.
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給藥途徑
禁忌症
- Known hypersensitivity to flumazenil or other benzodiazepines
- Patients receiving benzodiazepines for life-threatening conditions (e.g., status epilepticus, increased intracranial/CSF pressure)
- Serious tricyclic antidepressant (TCA) overdose
- Mixed overdoses where benzodiazepine reversal may precipitate seizures
- Baclofen or carisoprodol overdoses (may worsen clinical signs)
- Suspected tricyclic antidepressant overdose (can precipitate seizures)
- Patients receiving long-term benzodiazepine administration for seizure control or sedation (relative contraindication)
不良反應
- Injection site reactions
- Vomiting
- Cutaneous vasodilatation
- Vertigo
- Ataxia
- Blurred vision
- Seizures (especially in patients with a history of chronic benzodiazepine use or tricyclic antidepressant toxicity)
- Potentially teratogenic at high dosages
- Seizures (especially in patients receiving long-term benzodiazepine therapy)
- Re-sedation (due to short half-life)
- Agitation or anxiety upon rapid awakening
藥物相互作用
- Cyclic Antidepressants (e.g., clomipramine, amitriptyline) · Increased risk for seizures; concurrent use is contraindicated.
- Neuromuscular Blocking Agents · Not recommended to use flumazenil until neuromuscular blockade has been fully reversed.
- Tricyclic antidepressants (TCAs) · Can precipitate seizures in patients with suspected TCA overdose · major
- Benzodiazepines (Diazepam, Midazolam, etc.) · Antagonizes therapeutic effects (intended interaction) · major
- Tricyclic antidepressants · Increased risk of seizures if flumazenil is administered during a TCA overdose. · major
監測
- Efficacy of reversal (level of consciousness, respiratory rate)
- Monitor for re-sedation after 1-2 hours due to short half-life
- Monitor for seizures in susceptible patients
- Respiratory rate and depth
- Level of consciousness and sedation (monitor for re-sedation after 1 hour)
- Seizure activity
過量
Large IV overdoses have rarely caused symptoms in otherwise healthy humans. If seizures are precipitated by an overdose or rapid reversal, they have been successfully treated with barbiturates, benzodiazepines, and phenytoin, usually with prompt responses.
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