加巴噴丁
加巴噴丁是γ-氨基丁酸（GABA）的結構類似物，在獸醫學中廣泛用於其**神經病理性鎮痛**和**抗癲癇**特性。 * **鎮痛作用**：對慢性、適應不良和神經病理性疼痛（例如骨關節炎、椎間盤疾病、癌症疼痛）非常有效。通常作為多模式鎮痛方案的一部分。 * **癲癇管理**：用作難治性或複雜部分性癲癇發作的輔助抗癲癇藥物（AED），但作為單一藥物的療效有限。 * **行為/抗焦慮**：越來越多地在貓和狗中標示外使用，以減少就診或壓力事件前的恐懼、焦慮和壓力（FAS）。
作用機制: Despite its name, gabapentin does *not* bind to GABA receptors, nor does it affect GABA synthesis or uptake. * Binds selectively to the **α2-δ (alpha-2-delta) subunit** of **voltage-gated calcium channels (CaV)** in the central nervous system. * **Inhibition of Calcium Influx** → Decreased presynaptic calcium currents. * **Reduced Neurotransmitter Release** → Suppresses the release of excitatory neurotransmitters including **glutamate**, **substance P**, and **norepinephrine** in the dorsal horn of the spinal cord. * This dampens neuronal excitability, effectively preventing **allodynia** (pain from non-noxious stimuli) and **hyperalgesia** (exaggerated pain response).
各物種劑量
- Ancillary therapy of refractory seizures · 5-10 mg/kg · PO · q8-12h
- Ancillary therapy of refractory seizures · 5 mg/kg · PO · three times daily
- Ancillary therapy of refractory seizures · 10-30 mg/kg · PO · q8-12h
- Analgesic · 1.25-10 mg/kg · PO · q24h
- Adjunctive treatment of chronic or cancer pain · 3 mg/kg · PO · once a day
- Adjunctive analgesia associated with neuropathic pain · 2.5-5 mg/kg · PO · q12h · Author starts at 5 mg/kg and increases (up to 10 mg/kg) if no effect seen in two hours. Wean off slowly. Reduce in renal insufficiency.
- Analgesic · 5-10 mg/kg · PO · 2-3 times a day · Most VIN consultants recommend this dose.
- Analgesic · 50 mg (total dose) per cat · PO · 1-3 times a day
- Adjunctive seizure therapy / Chronic pain · 5-10 mg/kg · PO · q8-12h · starting dose; incremental dose increases are recommended
- Ancillary therapy of refractory seizures · 10-20 mg/kg · PO · q6-8h · Author notes gabapentin is the least effective of the newer antiepileptic drugs, particularly in dogs.
- Ancillary therapy of refractory seizures · 10-30 mg/kg · PO · q8-12h
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
- Hypersensitivity to gabapentin
- Use of xylitol-containing human oral solutions in dogs
- Oral solutions containing xylitol (highly toxic to dogs)
不良反應
- Sedation
- Ataxia
- Dizziness (humans)
- Somnolence
- Peripheral edema (humans)
- Withdrawal-precipitated seizures (if abruptly discontinued)
- Increased rate of pancreatic adenocarcinoma (noted in male rats)
- Mild sedation
- False-positive urinary protein tests (reported in humans)
- Hepatic toxicity (rare, reported in humans)
藥物相互作用
- Antacids · Oral antacids given concurrently may decrease oral bioavailability of gabapentin by 20%; separate doses by at least 2 hours.
- Hydrocodone · Co-administration may increase gabapentin AUC and efficacy/adverse effects. Gabapentin may reduce hydrocodone AUC, potentially reducing its effectiveness.
- Morphine · May increase gabapentin levels.
- Antacids (containing aluminium and magnesium) · Reduced absorption of gabapentin from the GI tract. Administer gabapentin at least 2 hours after antacids. · moderate
- Cimetidine · Reduced renal clearance of gabapentin (not considered clinically important). · minor
監測
- Clinical efficacy (reduction in pain scores or seizure frequency)
- Adverse effects (sedation, ataxia)
- Renal function (in patients with pre-existing disease)
- Clinical response (pain scores, seizure frequency)
- Renal and hepatic function in compromised patients
過量
In humans, massive overdoses (up to 49 grams) have been reported without fatality. * **Clinical Signs**: Ataxia, lethargy, somnolence, vomiting, and diarrhea. * **Xylitol Toxicity Risk**: The human oral solution contains 300 mg/mL of xylitol. Doses as low as 0.33 mL/kg of this solution can cause severe hypoglycemia or hepatotoxicity in dogs. * **Treatment**: Primarily supportive. General decontamination (emesis, activated charcoal, cathartics) if caught early. The drug can be removed via hemodialysis. If xylitol toxicity is suspected secondary to the human liquid formulation, aggressive treatment for hypoglycemia and liver protection is required; contact an animal poison control center.
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。