アミオダロン
Amiodarone
Amiodarone hydrochloride
別名: Cordarone · Pacerone · Nexterone · amiodaroni hydrochloridum · L3428 · 51087N · SKF-33134-A · Amiodaronum
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 |
|---|---|---|---|---|---|
| For atrial fibrillation or ventricular arrhythmias primarily in ambulatory patients | 8-10 mg/kg PO every 12 hours | PO | q12h | — | 🌎 NA |
| For ventricular arrhythmias secondary to occult cardiomyopathy in Doberman pinschers | 10 mg/kg PO twice daily for one week and then 8 mg/kg PO once daily. After 6 months reduce to 5 mg/kg PO once daily. | PO | q12h then q24h | Long-term | 🌎 NA |
| For ventricular tachycardia when other first line drugs (Class I antiarrhythmics ± beta-blockers) are ineffective | 10 mg/kg PO q12h for one week and then 5 mg/kg PO q12h for maintenance. | PO | q12h | Long-term | 🌎 NA |
| For SVTs or Vtach | 10-20 mg/kg PO once daily (q24h) loading for 5-7 days; 5-10 mg/kg PO once daily thereafter. | PO | q24h | Long-term | 🌎 NA |
| Ventricular and supraventricular arrhythmias, atrial fibrillation, ventricular pre-excitation syndromes | Dose not specified in monograph | PO/IV | Not specified | Not specified | 🌍 EU |
- For atrial fibrillation or ventricular arrhythmias primarily in ambulatory patients: Use caution if patient has bradycardia, AV blocks, or thyroid disorders.
- For ventricular arrhythmias secondary to occult cardiomyopathy in Doberman pinschers: For severe V-Tach, mexiletine is added at 5-8 mg/kg three times daily for one week. Once efficacy confirmed, patient weaned off mexiletine.
- Ventricular and supraventricular arrhythmias, atrial fibrillation, ventricular pre-excitation syndromes: Use as an IV infusion for recent onset atrial fibrillation has variable efficacy for restoring sinus rhythm but a high frequency of severe adverse effects.
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| For conversion of atrial fibrillation or ventricular tachycardia | 5 mg/kg/hr for one hour, followed by 0.83 mg/kg/hr for 23 hours and then 1.9 mg/kg/hour for the following 30 hours. | IV | CRI | Up to 54 hours | 🌎 NA |
- For conversion of atrial fibrillation or ventricular tachycardia: Infusion was discontinued when conversion occurred or when any side effects were noted. Regimen should be further adapted based upon PK/PD studies.
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
アミオダロンは、重度で難治性の心室性および上室性不整脈に主に使用される、強力で広域スペクトルのクラスIII抗不整脈薬です。
複雑な薬物動態プロファイルと重大な毒性の可能性があるため、通常は従来の毒性の低い治療法が効果を示さない場合にのみ使用されます。
臨床のポイント：
- 構造的には、アミオダロンはヨウ素化ベンゾフラン誘導体です。200mgの錠剤には約75mgのヨウ素が含まれており、甲状腺機能に影響を与える可能性があります。
- 脂溶性が非常に高く、組織に広く分布し脂肪組織に蓄積するため、半衰期が非常に長く変動しやすい特徴があります。
- 獣医学においては、特に潜在性拡張型心筋症（DCM）を患い、急速な幅広い心室頻拍や失神を呈するドーベルマン・ピンシャーに最もよく使用されます。
- 副作用（肝毒性や甲状腺機能障害など）のリスクが高いため、厳密なモニタリングが不可欠です。
作用機序
Amiodarone is uniquely versatile, possessing properties of all four Vaughan-Williams antiarrhythmic classes, though it is primarily classified as a Class III agent.
- Class III (Primary): Blocks potassium (K+) channels → prolongs phase 3 repolarization, action-potential duration (APD), and the effective refractory period (ERP) in myocardial cells.
- Class I: Blocks fast sodium (Na+) channels → slows conduction velocity.
- Class II: Non-competitively blocks beta-adrenergic receptors → provides sympatholytic effects, reducing heart rate.
- Class IV: Weakly blocks calcium (Ca2+) channels → slows AV node conduction and suppresses automaticity.
It is metabolized in the liver to its active metabolite, desethylamiodarone, which also contributes significantly to its antiarrhythmic effects.
安全性・警告
禁忌
- Hypersensitivity to amiodarone or iodine
- Severe sinus-node dysfunction
- Severe sinus bradycardia
- 2nd or 3rd degree AV block
- Bradycardial syncope
有害事象
- Vomiting
- Anorexia
- Hepatopathy (elevated liver enzymes, bilirubinemia)
- Bradycardia
- Neutropenia
- Thrombocytopenia
- Positive Coombs' test
- Corneal deposits
- Injection site pain (IV)
- Facial pruritus and hyperemia (IV)
- Hind limb weakness (horses)
- Diarrhea (horses)
注意事項
High Toxicity Potential: Clinical experience in veterinary patients is limited. Use only when other less toxic and more commonly used drugs are ineffective.
- Hepatic Effects: Hepatopathy can occur before clinical signs are noted; routine serial evaluation of liver enzymes and bilirubin is strongly recommended.
- Thyroid Function: May alter thyroid hormone levels (increases T4 and reverse T3, decreases T3) due to high iodine content.
- Pregnancy: FDA Category D. Embryotoxic in laboratory animals; congenital thyroid abnormalities detected in offspring. Use only if benefits outweigh risks.
医薬品相互作用
Significantly increases serum levels and/or pharmacologic/toxic effects of the anticoagulant.
Significantly increases serum levels and/or toxic effects of digoxin.
Increases cyclosporine levels; may increase creatinine.
Significantly increases serum levels and/or toxic effects of lidocaine.
Significantly increases serum levels and/or toxic effects with prolonged amiodarone administration.
Significantly increases serum levels and/or toxic effects of phenytoin.
Significantly increases serum levels and/or toxic effects of procainamide.
Significantly increases serum levels and/or toxic effects of quinidine.
Additive effects on QTc interval; possible serious arrhythmias.
Additive effects on QTc interval; possible serious arrhythmias.
Additive effects on QTc interval; possible serious arrhythmias.
Additive effects on QTc interval; possible serious arrhythmias.
Additive effects on QTc interval; possible serious arrhythmias.
Additive effects on QTc interval; possible serious arrhythmias.
Additive effects on QTc interval; possible serious arrhythmias.
Increased risks for hypotension or arrhythmias.
Possible potentiation of bradycardia, AV block, or sinus arrest.
Possible potentiation of bradycardia, AV block, or sinus arrest.
Increased amiodarone levels.
Possible hypotension, bradycardia.
Decreased amiodarone levels.
May significantly increase serum levels and/or pharmacological effects
May significantly increase serum levels and/or pharmacological effects
May significantly increase serum levels and/or pharmacological effects
May significantly increase serum levels and/or pharmacological effects
May significantly increase serum levels and/or pharmacological effects
監視
- ECG (for antiarrhythmic efficacy and proarrhythmic effects)
- Gastrointestinal signs (anorexia, vomiting)
- CBC (for neutropenia, thrombocytopenia)
- Serial liver enzymes and bilirubin (baseline and routine monitoring)
- Thyroid function tests
- Blood pressure
- Pulmonary radiographs (if clinical signs such as dyspnea or cough occur)
薬物動態
半減期
吸収
Oral absorption is slow and variable. In horses, oral bioavailability is low (6-34%). In humans, bioavailability ranges from 22-86%.
分布
Widely distributed throughout the body and highly lipophilic, accumulating in adipose tissue. In horses, it has a high apparent volume of distribution (31 L/kg) and is highly bound to plasma proteins (96%).
代謝
Metabolized by the liver into the active metabolite desethylamiodarone.
消失
Clearance in horses is 0.35 L/kg/hr. Neither amiodarone nor its active metabolite are dialyzable.
過剰投与
Clinical overdosage experience is limited.
Expected Signs:
- Hypotension
- Bradycardia
- Cardiogenic shock
- AV block
- Hepatotoxicity
Treatment:
- Therapy is primarily supportive.
- Bradycardia may be managed with a pacemaker or beta-1 agonists (e.g., isoproterenol).
- Hypotension may be managed with positive inotropic agents or vasopressors.
- Note: Neither amiodarone nor its active metabolite are dialyzable.
製品
製剤
- Oral tablets
- Injection solution
- Compounded oral suspension
ヒト用医薬品
- Amiodarone Oral Tablets: 100 mg, 200 mg & 400 mg (Cordarone, Pacerone, generic)
- Amiodarone Injection Solution: 50 mg/mL in 3 mL, 10 mL & 30 mL single-dose vials, 18 mL multiple-dose vials & 3 mL prefilled syringes (Nexterone, generic)
規制ステータス
Human-approved products used off-label under the cascade.
POM (Prescription Only Medicine). Used under the prescribing cascade.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Tablets should be stored in tight containers at room temperature and protected from light. Injection should be stored at room temperature and protected from light or excessive heat (light protection is not necessary during active IV administration). Compounded oral suspension (5 mg/mL in Ora-Plus/Ora-Sweet) retains >90% potency for 91 days when stored at 5°C and protected from light.
飼主向け情報
あなたのペットには、重度で生命を脅かす可能性のある不整脈を治療するためにアミオダロンが処方されました。これは非常に強力な薬であるため、慎重なモニタリングが必要です。
- インフォームド・コンセント： ペットに対するこの薬の使用経験は限られており、毒性のリスクがあるため、獣医師は治療を開始する前にリスクと利点について説明します。
- 投与方法： 処方された通りに正確に投与してください。獣医師に相談することなく、投与を飛ばしたり、急に薬をやめたりしないでください。
- 注意すべき副作用： ペットが食事をとらなくなったり、嘔吐したり、異常にだるそうにしたり、咳が出たり、呼吸困難になった場合は、すぐに獣医師に連絡してください。
- 定期検査： 肝臓や甲状腺の機能を監視するための定期的な血液検査や、薬が安全に効いているかを確認するための定期的な心電図（ECG）検査が必要になります。
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。