ガバペンチン
Gabapentin
1-(aminomethyl)cyclohexaneacetic acid
別名: Neurontin · Aclonium · Equipax · Gantin · Gabarone · Neurostil · Progresse · CI-945 · GOE-3450 · Gabapentinum
VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
動物種別用量
🌎 NA — North America🌍 EU — Europe
犬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Ancillary therapy of refractory seizures | 10-20 mg/kg | PO | q6-8h | — | 🌎 NA |
| Ancillary therapy of refractory seizures | 10-30 mg/kg | PO | q8-12h | — | 🌎 NA |
| Ancillary therapy of refractory seizures | 25-60 mg/kg/day divided q6-8h | PO | q6-8h | — | 🌎 NA |
| Ancillary therapy of refractory seizures | 10 mg/kg | PO | q8h | 3 months | 🌎 NA |
| Ancillary therapy of refractory seizures | 10-30 mg/kg | PO | q8h | — | 🌎 NA |
| Adjunctive treatment of chronic or cancer pain | 3 mg/kg | PO | once a day | — | 🌎 NA |
| Analgesic | 1.25-10 mg/kg | PO | q24h | — | 🌎 NA |
| Analgesic | 5-10 mg/kg | PO | 2-3 times a day | — | 🌎 NA |
| Analgesic | 2.5-10 mg/kg (up to 15 mg/kg) | PO | 1-3 times a day | — | 🌎 NA |
| Adjunctive seizure therapy / Chronic pain | 10-20 mg/kg | PO | q6-8h | — | 🌍 EU |
- Ancillary therapy of refractory seizures: Author notes gabapentin is the least effective of the newer antiepileptic drugs, particularly in dogs.
- Ancillary therapy of refractory seizures: Author initially uses 10 mg/kg PO q8h.
- Ancillary therapy of refractory seizures: For uncontrolled seizures when phenobarbital and potassium bromide levels were therapeutic, or sub-therapeutic but had unacceptable side effects.
- Analgesic: Most VIN consultants recommend this dose.
- Adjunctive seizure therapy / Chronic pain: starting dose; incremental dose increases are recommended
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Ancillary therapy of refractory seizures | 5-10 mg/kg | PO | q8-12h | — | 🌎 NA |
| Ancillary therapy of refractory seizures | 5 mg/kg | PO | three times daily | — | 🌎 NA |
| Ancillary therapy of refractory seizures | 10-30 mg/kg | PO | q8-12h | — | 🌎 NA |
| Analgesic | 1.25-10 mg/kg | PO | q24h | — | 🌎 NA |
| Adjunctive treatment of chronic or cancer pain | 3 mg/kg | PO | once a day | — | 🌎 NA |
| Adjunctive analgesia associated with neuropathic pain | 2.5-5 mg/kg | PO | q12h | — | 🌎 NA |
| Analgesic | 5-10 mg/kg | PO | 2-3 times a day | — | 🌎 NA |
| Analgesic | 50 mg (total dose) per cat | PO | 1-3 times a day | — | 🌎 NA |
| Adjunctive seizure therapy / Chronic pain | 5-10 mg/kg | PO | q8-12h | — | 🌍 EU |
- Adjunctive analgesia associated with neuropathic pain: 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: Most VIN consultants recommend this dose.
- Adjunctive seizure therapy / Chronic pain: starting dose; incremental dose increases are recommended
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
概要
ガバペンチンはγ-アミノ酪酸（GABA）の構造類似体であり、獣医療において主に神経障害性疼痛の鎮痛および抗てんかん作用のために広く使用されています。
- 鎮痛作用：慢性疼痛、不適応疼痛、神経障害性疼痛（変形性関節症、椎間板疾患、がん性疼痛など）に非常に有効です。多くの場合、マルチモーダル鎮痛プロトコルの一部として使用されます。
- てんかん管理：難治性または複雑部分発作の補助的な抗てんかん薬（AED）として使用されますが、単独での有効性は限られています。
- 行動/抗不安：動物病院への訪問やストレスの多い出来事の前に、恐怖、不安、ストレス（FAS）を軽減するために、犬や猫で適応外使用されることが増えています。
作用機序
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).
安全性・警告
禁忌
- Hypersensitivity to gabapentin
- Use of xylitol-containing human oral solutions in dogs
- Oral solutions containing xylitol (highly toxic to dogs)
有害事象
- 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)
注意事項
WARNING: Commercially available human oral solutions (e.g., Neurontin) often contain xylitol (up to 300 mg/mL), which is highly toxic to dogs, causing severe hypoglycemia and hepatotoxicity. Avoid use in dogs.
- Renal Insufficiency: Eliminated primarily via the kidneys. Use with caution and consider dosage adjustments in patients with renal impairment. Dogs partially metabolize the drug (30-40%), so mild to moderate renal dysfunction may not require adjustment.
- Withdrawal: Abrupt discontinuation can lead to withdrawal-precipitated seizures. Taper the dose gradually when discontinuing, especially in epileptic patients.
- Laboratory Alterations: May cause false-positive urinary protein readings on Ames N-Multistix SG dipstick tests. Use a sulfosalicylic acid precipitation test instead.
医薬品相互作用
Oral antacids given concurrently may decrease oral bioavailability of gabapentin by 20%; separate doses by at least 2 hours.
Co-administration may increase gabapentin AUC and efficacy/adverse effects. Gabapentin may reduce hydrocodone AUC, potentially reducing its effectiveness.
May increase gabapentin levels.
Reduced absorption of gabapentin from the GI tract. Administer gabapentin at least 2 hours after antacids.
Reduced renal clearance of gabapentin (not considered clinically important).
監視
- 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
薬物動態
半減期
吸収
Dogs: Oral bioavailability ~80% at 50 mg/kg. Peak plasma levels at 2 hours. Cats: Bioavailability ~90% (high interpatient variation 50-120%). Peak levels at 100 minutes. Horses: Rapidly absorbed, peak levels within 2 hours.
分布
Cats: Volume of distribution is relatively low (Vdss 0.65 L/kg). Humans: Minimally bound to plasma proteins; CSF levels are ~20% of plasma levels.
代謝
Dogs: Partially metabolized (30-40%) to N-methyl-gabapentin. Humans: Not significantly metabolized.
消失
Primarily via renal routes (excreted unchanged in urine in humans). Cats: Clearance ~3 mL/min/kg.
過剰投与
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.
製品
製剤
- Capsules
- Tablets
- Compounded Oral Suspension
- 100 mg capsule
- 300 mg capsule
- 400 mg capsule
- 600 mg film-coated tablet
- 800 mg film-coated tablet
- 50 mg/ml oral solution
ヒト用医薬品
- Gabapentin Oral Capsules & Tablets: 100 mg, 300 mg, 400 mg, 600 mg, 800 mg (Neurontin, generic)
- Gabapentin Oral Solution: 250 mg/5mL (50 mg/mL) (Neurontin) - Contains xylitol! Use with caution in dogs.
- Neurontin 100 mg, 300 mg, 400 mg capsules
- Neurontin 600 mg, 800 mg film-coated tablets
- Neurontin 50 mg/ml oral solution
規制ステータス
POM CD Schedule 3
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Capsules and tablets: Store at room temperature (25°C / 77°F); excursions permitted to 15-30°C. Oral liquid: Store in the refrigerator at 2-8°C (36-46°F). Compounded suspensions are most stable at pH 5.5-6.5.
飼主向け情報
ガバペンチンとは？ ガバペンチンは、慢性の神経痛の治療や、頻度は低いもののてんかん発作のコントロールを助けるために使用される薬です。また、動物病院への訪問などのストレスの多い出来事の前に、恐怖や不安を軽減するためにもよく使用されます。
投薬方法
- 食事の有無にかかわらず投与できます。
- 人間用の液体製剤（ニューロンチン）は、犬にとって非常に毒性が高く致命的な可能性のある人工甘味料であるキシリトールを含んでいるため、獣医薬局で特別に調剤された場合を除き、絶対に犬に与えないでください。
注意すべきこと
- 最も一般的な副作用は眠気（鎮静）とふらつき（運動失調）です。これらの副作用は通常軽度であり、ペットが薬に慣れるにつれて改善することが多いです。
- ペットが過度に眠そうにしていたり、極端に動きがぎこちない場合は、獣医師に連絡してください。
重要な注意事項
- ペットがてんかん発作のためにガバペンチンを服用している場合、急に薬を中止しないでください。重篤な離脱発作を引き起こす可能性があります。用量を変更する前に、必ず獣医師に相談してください。
VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。