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托吡酯

Topiramate

Sulfamate-substituted derivative of D-fructose

抗癲癇藥PO狗貓

別名: Topamax · Topiragen · Epitomax · Topamac · Topimax · McN-4853 · RWJ-17021 · Topiramatum

由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本

5-10 mg/kg PO q12hPO· q12h
— 🐕

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。

各物種劑量

🌎 NA — North America🌍 EU — Europe

狗

適應症劑量途徑頻次療程地區
Alternative second line anticonvulsant5-10 mg/kg PO q12hPOq12h—🌎 NA
Alternative treatment for refractory generalized and focal seizures5-10 mg/kg PO twice dailyPOtwice daily—🌎 NA
Seizures (Initial dose)2-10 mg/kg PO q12hPOq12h—🌎 NA
Seizures5-10 mg/kg PO twice dailyPOtwice daily—🌎 NA
Refractory epilepsy2.5-5 mg/kg PO three times dailyPOthree times daily—🌎 NA
  • Seizures: Start at the lower dosage to reduce adverse effects.
  • Refractory epilepsy: Presently, the author is using this drug at this dose, but at this stage there is not enough data to know how effective this treatment will be.

貓

適應症劑量途徑頻次療程地區
Automatisms (running fits) and focal seizure activity12.5-25 mg PO (total dose) q8-12hPOq8-12h—🌎 NA
  • Automatisms (running fits) and focal seizure activity: Gradual adaptation in dosing is recommended. Inappetence is a major adverse effect with higher doses.

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。

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概覽

​托吡酯 (Topiramate)​ 是一種新型的第二代​抗癲癇藥物​，主要作為犬貓難治性癲癇的附加（輔助）治療。

  • ​臨床應用​：對於控制​局部性（病灶性）癲癇​及自動症（例如貓的「奔跑性發作」）特別有效。
  • ​藥代動力學特徵​：在狗體內的半衰期極短（2-4小時），但由於其對大腦受體具有高親和力，儘管清除迅速，仍能維持持續的治療活性。
  • ​治療角色​：通常在傳統第一線療法（如苯巴比妥、溴化鉀或左乙拉西坦）無法有效控制癲癇時考慮使用。
  • ​實務考量​：目前已有學名藥上市，有助於降低治療成本，但頻繁的給藥頻率（狗通常需要一天三次）需要飼主的高度配合。

作用機制

Topiramate has a multimodal mechanism of action that dampens excitatory pathways and enhances inhibitory neurotransmission in the central nervous system:

  • Voltage-gated Sodium Channels → Blocks repetitive action potentials in a time-dependent manner, preventing the spread of seizure activity.
  • GABA Receptors → Increases the frequency of GABA activation at GABA_A receptors, enhancing inhibitory signals in the brain.
  • AMPA/Kainate Receptors → Antagonizes these specific glutamate receptors, directly blocking excitatory neurotransmission (without affecting NMDA receptors).
  • Carbonic Anhydrase → Weakly inhibits isoenzymes CA-II and CA-IV, though this is believed to play only a minor role in its overall antiepileptic efficacy.

安全性與警告

禁忌症

  • Known hypersensitivity to topiramate

不良反應

  • GI distress (dogs)
  • Inappetence (dogs, cats)
  • Irritability (dogs)
  • Sedation/Lethargy (cats, dogs)
  • Ataxia (dogs)
  • Somnolence (humans)
  • Dizziness (humans)
  • Acute myopia with secondary angle closure glaucoma (rare, humans)
  • Calcium phosphate renal calculi (humans)
  • Anorexia
  • Weight loss
  • Gastrointestinal upset

注意事項

Use with caution in patients with impaired hepatic or renal function. Topiramate can cause a hyperchloremic metabolic acidosis and reduce citrate excretion in the urine, increasing urine pH and leading to calcium phosphate renal calculi. It is an FDA Category C drug for pregnancy (teratogenic effects noted in mice and rats) and enters maternal milk; use with caution in nursing patients.

藥物相互作用

Amitriptyline

Topiramate may increase amitriptyline levels

Carbonic Anhydrase Inhibitors (acetazolamide, dichlorphenamide)

Concomitant use may increase the risk of renal stone formation

CNS DepressantsModerate

May exacerbate the adverse effects of topiramate

Lamotrigine

May increase topiramate levels

PhenytoinModerate

May decrease topiramate levels; phenytoin levels may increase

Valproic Acid

May decrease topiramate and VPA levels

PhenobarbitalModerate

May increase clearance and decrease plasma concentrations of topiramate

監測

  • Seizure frequency and severity (Efficacy)
  • Adverse effects (GI distress, sedation, inappetence)
  • Body weight and appetite
  • Renal function in compromised patients

藥物動力學

半衰期

狗2-4 hours

吸收

Rapidly absorbed after oral administration in dogs, but absolute bioavailability varies between 30-60%.

分佈

High affinity for receptors in the brain allows for sustained therapeutic activity.

代謝

Not extensively metabolized (in humans).

排除

About 70% is excreted unchanged in the urine (in humans).

過量

Overdoses in humans have caused convulsions, drowsiness/lethargy, slurred speech, blurred and double vision, impaired mentation/stupor, ataxia, metabolic acidosis, hypotension, agitation, and abdominal pain. In dogs, common findings reported to the ASPCA APCC include ataxia and lethargy.

Treatment:

  • Gut emptying protocols if the ingestion was recent.
  • Supportive therapy.
  • Hemodialysis is effective in enhancing the elimination of topiramate from the body.

可用產品

劑型

  • Tablets
  • Sprinkle capsules
  • 25 mg tablet
  • 50 mg tablet
  • 100 mg tablet
  • 200 mg tablet
  • 15 mg sprinkle capsule
  • 25 mg sprinkle capsule
  • 50 mg sprinkle capsule
  • 15 mg capsule
  • 25 mg capsule
  • 50 mg capsule

人用標示

  • Topiramate Tablets: 25 mg, 50 mg & 100 mg (Topamax, Topiragen, generic)
  • Topiramate Sprinkle Capsules: 15 mg & 25 mg (Topamax, generic)
  • Topamax 25 mg, 50 mg, 100 mg, 200 mg tablets
  • Topamax 15 mg, 25 mg, 50 mg sprinkle capsules

各地核准狀態

United Kingdom✗ 未核准處方藥VMD

POM (Prescription Only Medicine). Used under the prescribing cascade.

暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

儲存與穩定性

Tablets should be stored in tight containers at room temperature (15-30°C; 59-86°F); protect from moisture. Sprinkle capsules should be stored in tight containers at temperatures below 25°C (76°F); protect from moisture.

飼主須知

​重要提示​：絕對不可突然停用此藥物，否則可能引發嚴重的「反彈性」癲癇發作。在更改劑量前，請務必諮詢您的獸醫師。

  • ​給藥方式​：可與食物一起或空腹給予。如果您的寵物出現腸胃不適，請嘗試與少量食物一起餵食。
  • ​行為改變​：在開始用藥或增加劑量時，請密切觀察寵物是否有煩躁、嗜睡或食慾不振的跡象。如果出現這些情況，請聯繫您的獸醫師。
  • ​癲癇日記​：請詳細記錄任何癲癇發作的情況（日期、時間、持續時間和嚴重程度），以幫助獸醫師評估藥物是否有效。
  • ​飼主配合​：因為此藥物在狗體內代謝非常快，您可能需要嚴格按照處方，每天給藥 2 到 3 次。
  • ​預期心理​：此藥物在獸醫臨床上的應用相對屬於「試驗性質」，通常是在其他藥物無效時才會使用。

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