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カルバマゼピン

Carbamazepine

5H-Dibenz[b,f]azepine-5-carboxamide

抗てんかん薬 / 神経障害性疼痛治療薬 / 行動調整薬PO犬馬

別名: Tegretol · Carbatrol · Epitol · Equetro · G-32883 · carbamazepinum · karbamatsepiini · karbamazepinas

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

4-8 mg/kg PO q12hPO· q12h
— 🐕

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
As a psychotherapeutic agent4-8 mg/kg PO q12hPOq12h—🌎 NA
  • As a psychotherapeutic agent: Not commonly used, but may have some utility in dogs that seem to have amygdalar hyperactivity; sometimes used in conjunction with SSRIs to control explosive aggression.

馬

適応用量経路頻度期間地域
For photic head shaking10 mg/kg PO q6h or 29 mg/kg PO q12hPOq6h or q12h—🌎 NA
  • For photic head shaking: May be helpful in some horses that do not respond to cyproheptadine.

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。

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概要

カルバマゼピンは、三環系抗うつ薬イミプラミンと化学的に関連するジベンゾアゼピンイミノスチルベン誘導体です。

​臨床上のポイント：​ ヒト医療では主要な抗てんかん薬および気分安定薬として広く使用されていますが、獣医療（特に犬）での有用性は、急速な肝臓の自己誘導（オートインダクション）によって厳しく制限されます。犬は治療開始後数日でこの薬物を非常に速く代謝するため、治療的な血清濃度を維持することが極めて困難になります。

この薬物動態学的な制限のため、動物のてんかん発作のコントロールに使用されることは稀です。その代わり、獣医療では主に以下の目的で使用されます：

  • 犬の​行動治療​（例：扁桃体の過活動や爆発的な攻撃性の管理。しばしばSSRIと併用される）。
  • 馬の​神経障害性疼痛​や、シプロヘプタジンなどの他の治療に反応しない​光過敏性ヘッドシェイキング​などの特定の神経疾患。

作用機序

Carbamazepine primarily acts by blocking voltage-gated sodium channels in neuronal membranes.

  • ​Mechanism:​ Binds preferentially to the inactive state of sodium channels → delays their recovery → inhibits repetitive neuronal firing and stabilizes hyperexcited neural membranes.
  • It also decreases the synaptic transmission of excitatory impulses and may reduce the release of the excitatory neurotransmitter glutamate.
  • Structurally related to tricyclic antidepressants, it also possesses mild anticholinergic, antidiuretic, and muscle relaxant properties.

安全性・警告

禁忌

  • Patients receiving MAO Inhibitors (e.g., selegiline) within the past 14 days
  • Patients with a history of bone marrow depression
  • Known hypersensitivity to carbamazepine or tricyclic antidepressants

有害事象

  • Sedation and lethargy
  • Ataxia (unsteadiness)
  • Gastrointestinal upset (vomiting, anorexia)
  • Hepatotoxicity (elevated liver enzymes)
  • Blood dyscrasias (rare but possible bone marrow suppression)

注意事項

Use with extreme caution due to extensive drug interactions (it is a potent inducer of hepatic enzymes). In dogs, it rapidly induces its own metabolism (autoinduction), making long-term therapeutic dosing difficult. May interfere with thyroid function tests (decreased values) and some pregnancy tests, though veterinary significance is unclear.

医薬品相互作用

Azole Antifungals (e.g., Ketoconazole, Itraconazole)

May increase plasma levels or effects of carbamazepine

Calcium Channel Blockers (e.g., Diltiazem, Verapamil)

May increase plasma levels or effects of carbamazepine; Carbamazepine may also decrease their effects

Cimetidine

May increase plasma levels or effects of carbamazepine

Danazol

May increase plasma levels or effects of carbamazepine

Grapefruit Juice

May increase plasma levels or effects of carbamazepine

Isoniazid

May increase plasma levels or effects of carbamazepine; Carbamazepine may also increase effects of Isoniazid

Macrolides (e.g., Erythromycin, Clarithromycin)

May increase plasma levels or effects of carbamazepine

MAO Inhibitors (e.g., Selegiline)

Contraindicated; discontinue MAOI at least 14 days prior to carbamazepine

Niacin

May increase plasma levels or effects of carbamazepine

SSRI Antidepressants (e.g., Fluoxetine)

May increase plasma levels or effects of carbamazepine

Tricyclic Antidepressants (e.g., Clomipramine, Amitriptyline)

May increase plasma levels or effects of carbamazepine; Carbamazepine may also decrease their effects, though it can increase Clomipramine levels

Valproic Acid

May increase plasma levels or effects of carbamazepine; Carbamazepine may decrease its effects and increase risk for phenobarbital toxicity

Barbiturates (e.g., Phenobarbital)

May decrease plasma levels or effects of carbamazepine

Cisplatin

May decrease plasma levels or effects of carbamazepine

Doxorubicin

May decrease plasma levels or effects of carbamazepine

Felbamate

May decrease plasma levels or effects of carbamazepine

Phenytoin

May decrease plasma levels or effects of carbamazepine

Primidone

May decrease plasma levels or effects of carbamazepine

Rifampin

May decrease plasma levels or effects of carbamazepine

Theophylline

May decrease plasma levels or effects of carbamazepine

Acetaminophen

Carbamazepine may decrease its effect by lowering serum concentrations

Benzodiazepines

Carbamazepine may decrease its effect by lowering serum concentrations

Bupropion

Carbamazepine may decrease its effect by lowering serum concentrations

Buspirone

Carbamazepine may decrease its effect by lowering serum concentrations

Cyclosporine

Carbamazepine may decrease its effect by lowering serum concentrations

Doxycycline

Carbamazepine may decrease its effect by lowering serum concentrations

Glucocorticoids

Carbamazepine may decrease its effect by lowering serum concentrations

Lamotrigine

Carbamazepine may decrease its effect by lowering serum concentrations

Levothyroxine

Carbamazepine may decrease its effect by lowering serum concentrations

Methadone

Carbamazepine may decrease its effect by lowering serum concentrations

Mirtazapine

Carbamazepine may decrease its effect by lowering serum concentrations

Non-depolarizing muscle blockers (e.g., Atracurium)

Carbamazepine may decrease its effect by lowering serum concentrations

Praziquantel

Carbamazepine may decrease its effect by lowering serum concentrations

Topiramate

Carbamazepine may decrease its effect by lowering serum concentrations

Tramadol

Carbamazepine may decrease its effect by lowering serum concentrations

Zonisamide

Carbamazepine may decrease its effect by lowering serum concentrations

Trazodone

Carbamazepine may decrease its effect by lowering serum concentrations

Warfarin

Carbamazepine may decrease its effect by lowering serum concentrations

監視

  • Complete Blood Count (CBC)
  • Liver function tests
  • Clinical efficacy and behavioral changes

薬物動態

半減期

犬Initially ~15 hours, but drops to 1-2 hours after chronic dosing due to autoinduction.

吸収

Variable and relatively slow oral absorption.

分布

Widely distributed into tissues; highly protein-bound.

代謝

Extensively metabolized in the liver. In dogs, it is a potent inducer of hepatic microsomal enzymes and rapidly induces its own metabolism (autoinduction) within days of starting therapy.

消失

Excreted primarily in the urine as metabolites.

過剰投与

Overdose can lead to significant CNS depression, severe ataxia, tremors, seizures, respiratory depression, and cardiovascular abnormalities (tachycardia, hypotension). Treatment is primarily supportive and symptomatic, including gastric decontamination if caught early, IV fluids, and respiratory support. Seizures should be treated with standard anticonvulsants (e.g., diazepam, phenobarbital).

製品

製剤

  • Oral Tablets
  • Oral Chewable Tablets
  • Extended-Release Tablets/Capsules
  • Oral Suspension

ヒト用医薬品

  • Carbamazepine Oral Tablets: 100 mg (regular and chewable), & 200 mg (Tegretol, Epitol, generic)
  • Carbamazepine Oral Tablets or Capsules Extended-Release (12-hour) (Tegretol XR, Carbatrol, Equetro, generic)
  • Carbamazepine Oral Suspension (Tegretol, generic)

規制ステータス

規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Store below 30°C (86°F) in airtight containers, as humid conditions can reduce potency by up to one-third. Protect from light. Compounded oral suspension (40 mg/mL in simple syrup) retains >90% potency for 90 days stored at both 5°C and 25°C, but must be protected from light and shaken vigorously before use.

飼主向け情報

獣医師があなたのペットにカルバマゼピンを処方しました。以下の情報を注意深くお読みください：

  • ​適応外使用（Off-Label Use）：​ この薬は獣医療において「適応外使用」として用いられます。頻繁に使用される薬ではなく、獣医師はあなたのペットの特定の行動学的または神経学的な必要性に基づいて処方しています。
  • ​厳密なスケジュール：​ 処方された通りに正確に薬を与えることが非常に重要です。動物はこの薬を非常に速く処理するため、1回でも投与を忘れると効果が失われる可能性があります。多くの場合、頻繁な投与が必要です。
  • ​観察すべき点：​ ペットに無気力、ふらつき（運動失調）、または胃腸の不調（嘔吐、食欲不振）の兆候がないか観察してください。

​重要：​ 異常な行動、激しい嘔吐、または目や歯茎の黄色み（黄疸）に気づいた場合は、肝臓への負担や副作用の兆候である可能性があるため、すぐに獣医師に報告してください。

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。