費爾巴酯
**費爾巴酯 (Felbamate)** 是一種獨特的雙氨基甲酸酯類**抗癲癇藥物**，主要作為犬隻的二線或三線抗癲癇藥物。 * 對於**複雜部分性癲癇**和全身性癲癇特別有用。 * **臨床要點**：與許多其他抗癲癇藥物不同，費爾巴酯在與苯巴比妥或溴化鉀合用時，通常*不會*引起額外的鎮靜作用，這使其成為一種理想的附加療法。 * 由於其半衰期短，需要嚴格執行每日三次 (TID) 的給藥頻率。 * 成本和取得難易度可能是獸醫臨床上的限制因素。 * 由於在獸醫學中的使用有限，其完整的副作用概況可能尚不完全清楚。
作用機制: Felbamate reduces excitatory neurotransmission and enhances inhibitory pathways. * Increases activation of **voltage-gated sodium channels** → decreases sustained high-frequency firing of action potentials. * **NMDA Receptor Antagonism**: Blocks the **NR2B subunit** of the **NMDA receptor** → prevents glutamate-mediated excitation. * **GABA_A Modulation**: Acts as a positive allosteric modulator at **GABA_A receptors** → enhances chloride influx and neuronal hyperpolarization.
各物種劑量
- Seizures (As either add-on therapy or monotherapy) · 15 mg/kg PO q8h. Dose can be increased in 15 mg/kg increments every 2 weeks until seizures are controlled. Doses as high as 70 mg/kg q8h are required and tolerated in some dogs. · PO · q8h · Starting dose is 15 mg/kg.
- Seizures (As a third choice antiepileptic agent) · 15-65 mg/kg PO q8h · PO · q8h · Steady state reached after 4th oral dose. Monitor CBC and liver function tests as you would for phenobarbital. Therapeutic serum concentration reported to be 15-100 micrograms/mL.
- Seizures (For patients on phenobarb and bromides and seizure activity unchanged or having intolerable side effects) · 5-20 mg/kg PO three times daily · PO · TID · If intolerable side effects, do levels and decrease the dose of the one that is in the high end of the range. Then add felbamate.
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。
給藥途徑
禁忌症
- Hypersensitivity to felbamate or other carbamates (e.g., meprobamate)
不良反應
- Keratoconjunctivitis sicca (KCS)
- Liver enzyme induction
- Tremor
- Limb rigidity
- Salivation
- Restlessness and agitation (at high doses)
- Blood dyscrasias (thrombocytopenia, lymphopenia, leukopenia)
- Sedation (usually when combined with other anticonvulsants)
- Vomiting/nausea (usually when combined with other anticonvulsants)
藥物相互作用
- Phenobarbital · Felbamate may increase phenobarbital levels. Phenobarbital may decrease felbamate levels.
- Phenytoin · Felbamate may increase phenytoin levels. Phenytoin may decrease felbamate levels.
- Valproate · Felbamate can cause increases in valproic acid levels.
監測
- Liver function tests (q2-3 months recommended by some clinicians)
- Complete Blood Count (CBC) (q2-3 months recommended by some clinicians)
- Therapeutic drug levels (25-100 micrograms/mL range, though usefulness is questionable)
- Seizure frequency and severity
過量
Limited veterinary information is available. * In humans, a massive overdose (12 grams over 12 hours) resulted only in mild gastric distress and a slightly increased heart rate. * Treatment should be supportive and symptomatic. Consider gastric decontamination if ingestion is recent and the patient is neurologically stable.
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。