フェルバメート
**フェルバメート**は、主に犬の二次または三次抗てんかん薬として使用されるユニークなジカルバメート系**抗てんかん薬**です。 * **複雑部分発作**および全般発作に特に有用です。 * **臨床のポイント**：他の多くの抗てんかん薬とは異なり、フェノバルビタールや臭化カリウムと併用しても通常は追加の鎮静作用を引き起こさないため、魅力的な追加療法となります。 * 半減期が短いため、1日3回（TID）の厳密な投薬が必要です。 * 獣医療においては、費用と入手のしやすさが制限要因となる場合があります。 * 獣医療での使用実績が限られているため、副作用の全容は完全には解明されていません。
作用機序: 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.
動物種別の用量
- 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.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Hypersensitivity to felbamate or other carbamates (e.g., meprobamate)
有害事象
- 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)
薬物相互作用
- 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.
モニタリング
- 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
過量投与
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 の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。