ジゴキシン
Digoxin
別名: Cardoxin · Lanoxin PG · digoxinum · digoxosidum · digitalis
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 |
|---|---|---|---|---|---|
| CHF with atrial fibrillation in dogs with normal renal function | 0.005-0.0075 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Initial dosing for dogs weighing less than 20 kg | 0.005-0.011 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Initial dosing for dogs weighing more than 20 kg | 0.22 mg/m2 (NOT mg/kg) PO q12h | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of dilated cardiomyopathy patients with atrial fibrillation | 0.0025 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Adjunctive treatment of atrial fibrillation | 0.003-0.005 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Refractory heart failure or atrial fibrillation (if pimobendan unavailable) | 0.005 mg/kg PO twice a day | PO | q12h | — | 🌎 NA |
| Supraventricular arrhythmias | 0.22 mg/m2 (NOT mg/kg) PO q12h | PO | q12h | — | 🌎 NA |
| Management of supraventricular tachyarrhythmias | 2.5-3.5 μg/kg (based on lean body weight; decrease dose by 10% for elixir). Maximum dose 0.25 mg/dog. Start at lower end of dose range and up-titrate carefully. | PO | q12h | Long-term | 🌍 EU |
| Management of supraventricular tachyarrhythmias (Emergency/Rare) | 2.2-4.4 μg/kg | IV | q12h | As needed | 🌍 EU |
- CHF with atrial fibrillation in dogs with normal renal function: Trough level of 0.8-1.2 nanograms/mL is the recommended target.
- Initial dosing for dogs weighing less than 20 kg: Results in therapeutic range by second day. Monitor levels 3-5 days later.
- Initial dosing for dogs weighing more than 20 kg: Results in therapeutic range by second day. Monitor levels 3-5 days later.
- Adjunctive treatment of dilated cardiomyopathy patients with atrial fibrillation: Loading dose usually not given. Trough therapeutic level is 0.8-1.2 ng/mL.
- Refractory heart failure or atrial fibrillation (if pimobendan unavailable): Start with a low dose and round down if needed.
- Management of supraventricular tachyarrhythmias: Dose based on lean body weight. Decrease dose by 10% for elixir.
- Management of supraventricular tachyarrhythmias (Emergency/Rare): Only use IV if essentially indicated. Administer very slowly.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Dilated cardiomyopathy or advanced atrioventricular valve insufficiency | 0.007 mg/kg PO every other day | PO | q48h | — | 🌎 NA |
| Starting dose for normal cats weighing less than 3 kg | 1/4th of a 0.125 mg tablet administered every other day | PO | q48h | — | 🌎 NA |
| Starting dose for normal cats weighing 3 to 6 kg | 1/4th of a tablet every day | PO | q24h | — | 🌎 NA |
| Starting dose for normal cats weighing more than 6 kg | 1/4th of a tablet every day to q12h | PO | q12h-q24h | — | 🌎 NA |
| Management of supraventricular tachyarrhythmias | 10 μg/kg (equating to 1/4 of a 125 μg tablet). Start at lower dose range and titrate up. | PO | q24-48h | Long-term | 🌍 EU |
| Management of supraventricular tachyarrhythmias (Emergency/Rare) | 1-1.6 μg/kg | IV | q12h | As needed | 🌍 EU |
- Dilated cardiomyopathy or advanced atrioventricular valve insufficiency: Use lean body weight. Measure serum level 10+ days later, 8-10 hours after dosing. Therapeutic level: 1-2 ng/mL.
- Starting dose for normal cats weighing less than 3 kg: Tablets are better tolerated than the alcohol-based elixir.
- Starting dose for normal cats weighing 3 to 6 kg: Using 0.125 mg tablet.
- Starting dose for normal cats weighing more than 6 kg: Using 0.125 mg tablet.
- Management of supraventricular tachyarrhythmias: Cats are highly sensitive to toxicity.
- Management of supraventricular tachyarrhythmias (Emergency/Rare): Only use IV if essentially indicated. Administer very slowly.
小型哺乳類
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Dilated cardiomyopathy in Hamsters | 0.05-0.1 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
フェレット
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Dilated cardiomyopathy | 0.01 mg/kg PO once daily initially | PO | q24h | — | 🌎 NA |
| Maintenance | 0.005-0.01 mg/kg PO once to twice daily | PO | q12h-q24h | — | 🌎 NA |
| Dilated cardiomyopathy long-term maintenance | 0.01 mg/kg q24h | PO | q24h | Long-term | 🌎 NA |
- Dilated cardiomyopathy: Use oral liquid. May increase to twice daily if necessary.
- Maintenance: Using the elixir; monitor blood levels if possible.
- Dilated cardiomyopathy long-term maintenance: Used with furosemide (2 mg/kg q12h) and enalapril (0.5 mg/kg q48h).
鳥
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Emergency stabilization | 0.02-0.5 mg/kg q12h for 2-3 days, then decreased to 0.01 mg/kg q12-24h | PO/IM/IV | q12h then q12-24h | 2-3 days initial, then maintenance | 🌎 NA |
- Emergency stabilization: Because of very small therapeutic margin, best used for emergency stabilization rather than long-term therapy. Consider switching to an ACE inhibitor.
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Loading dose | 11 micrograms/kg IV given slowly or in divided doses, or 44 micrograms/kg PO | IV/PO | Once | — | 🌎 NA |
| Maintenance Dose | 2.2 micrograms/kg IV every 12h or 11 micrograms/kg PO every 12 hours | IV/PO | q12h | — | 🌎 NA |
- Loading dose: ARCI UCGFS Class 4 Drug
- Maintenance Dose: Maintain plasma concentrations between 0.5-2 ng/mL.
牛
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Normalize atrial rate | 0.25 mg/100 lbs body weight | PO | Titrate to effect | — | 🌎 NA |
- Normalize atrial rate: Not destroyed in rumen; not excreted in milk.
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
ジゴキシンは、主に陽性変力作用（心筋収縮力の増加）および陰性変時作用（心拍数の低下）を目的として使用される強心配糖体です。獣医学では、うっ血性心不全（CHF）や心房細動・粗動などの上室性頻脈性不整脈の治療に利用されます。
臨床上のポイント：
- 治療域が狭い： 治療量と中毒量の差が非常に小さいため、慎重な投与と薬物治療モニタリング（TDM）が不可欠です。
- 治療パラダイムの変化： 歴史的にはCHF管理の要でしたが、ピモベンダンのようなより安全で効果的な強心血管拡張薬の登場により、現在では犬や猫の心不全の第一選択薬とは見なされていません。現在は主に心房細動のレートコントロールとして、ジルチアゼムと併用されることが多いです。
- 投与量の基準： ジゴキシンは脂肪や腹水にはほとんど分布しないため、投与量は除脂肪体重に基づいて計算する必要があります。
- 動物種による感受性： 猫は犬に比べてジゴキシンの毒性に対して非常に敏感です。
作用機序
Digoxin exerts its effects through the reversible inhibition of the Na⁺/K⁺-ATPase pump in the myocardial cell membrane.
- Positive Inotropy (Contractility): Inhibition of Na⁺/K⁺-ATPase → Increased intracellular Na⁺ → Decreased driving force for the Na⁺/Ca²⁺ exchanger (NCX) → Decreased Ca²⁺ extrusion → Increased intracellular Ca²⁺ → Increased Ca²⁺ uptake into the sarcoplasmic reticulum. Upon the next action potential, more Ca²⁺ is released, leading to increased myocardial contractility.
- Negative Chronotropy/Dromotropy (Heart Rate/Conduction): Digoxin increases vagal (parasympathetic) tone → Decreased conduction velocity through the AV node and prolonged effective refractory period (ERP) → Slowed ventricular response rate in supraventricular arrhythmias.
- Neurohormonal Effects: At low doses, digoxin restores baroreceptor sensitivity, which decreases sympathetic outflow and reduces the neurohormonal activation seen in heart failure.
安全性・警告
禁忌
- Ventricular fibrillation
- Digitalis intoxication
- Hypertrophic cardiomyopathy in cats (relative contraindication, may increase myocardial oxygen demand and dynamic outflow obstruction)
- Frequent ventricular arrhythmias
- Atrioventricular (AV) block
- Feline hypertrophic cardiomyopathy
- Hypokalaemia
有害事象
- Cardiac arrhythmias (complete or incomplete heart block, bigeminy, ST segment changes, paroxysmal ventricular or atrial tachycardias, multifocal VPCs)
- Mild GI upset
- Anorexia
- Weight loss
- Diarrhea
- Vomiting (especially associated with IV injections)
- Diarrhoea
- Depression
- Arrhythmias (AV block, bigeminy, paroxysmal ventricular or atrial tachycardias with block, multiform VPCs)
- Vasoconstriction (with IV administration)
注意事項
Extreme Caution: Patients with glomerulonephritis and heart failure, or with idiopathic hypertrophic subaortic stenosis (IHSS).
- Caution: Severe pulmonary disease, hypoxia, acute myocarditis, myxedema, acute myocardial infarction, frequent VPCs, V-tach, chronic constrictive pericarditis, or incomplete AV block.
- Renal Disease: Principally eliminated by the kidneys; use with caution and monitor serum levels closely in patients with renal impairment.
- Electrolyte/Endocrine Imbalances: Animals that are hypernatremic, hypokalemic, hypercalcemic, hyper- or hypothyroid may require smaller dosages; monitor carefully.
- Cardioversion: Elective cardioversion of patients with atrial fibrillation should be postponed until digoxin has been withheld for 1-2 days.
- Dosing Weight: Dosing is generally based upon lean body weight as digoxin does not distribute well into ascitic fluid or fat.
医薬品相互作用
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels in dogs
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May reduce digoxin serum levels
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels (data conflicts); additive negative effects on AV conduction
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects; hypokalemia predisposes to digitalis toxicity
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels; rule of thumb is to decrease digoxin dose by 50% if used together
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels, decrease elimination rate, or enhance toxic effects
May increase serum levels; additive negative effects on AV conduction
Additive negative effects on AV conduction, complete heart block possible
May decrease serum levels of digoxin independent of route of digoxin dosing
May predispose the patient to digitalis toxicity via electrolyte imbalances (e.g., hypokalemia)
May enhance or decrease the toxic effects of digoxin
Patients on digoxin that receive thyroid replacement therapy may need their digoxin dosage adjusted
May decrease digoxin absorption from the GI tract
May increase serum level, decrease elimination rate, or enhance toxic effects
Can cause hypokalaemia, which strongly predisposes to digoxin toxicity
May increase serum level, decrease elimination rate, or enhance toxic effects
May decrease digoxin absorption from the GI tract
May decrease digoxin absorption from the GI tract
May decrease digoxin absorption from the GI tract
May decrease digoxin absorption from the GI tract
May cause hypokalaemia, which enhances the toxic effects of digoxin
May cause hypokalaemia, which enhances the toxic effects of digoxin
監視
- Serum digoxin levels (Trough levels recommended: Dogs 0.8-1.2 ng/mL; Cats 0.9-2 ng/mL; Other species 0.5-2 ng/mL. Wait at least 6 days after starting therapy to reach steady-state)
- Appetite and body weight
- Cardiac rate and ECG changes
- Serum electrolytes (especially potassium)
- Renal function tests
- Clinical efficacy for CHF (improved perfusion, decreased edema)
- Serum digoxin levels (check after 7-10 days, sample taken 6-8 hours post-pill. Ideal trough therapeutic level: 0.6-1.2 ng/ml)
- ECG (monitor for AV block and ventricular arrhythmias)
- Serum potassium levels (hypokalaemia increases toxicity risk)
- Renal function (BUN, Creatinine)
薬物動態
半減期
吸収
Variable depending on the oral dosage form. Food may delay, but not alter, the extent of absorption in most species. In cats, food reportedly decreases the amount absorbed by 50% after tablet administration. Peak serum levels occur within 45-60 minutes (elixir) and 90 minutes (tablet).
分布
Widely distributed with highest levels in kidneys, heart, intestine, stomach, liver, and skeletal muscle. Lowest concentrations in brain and plasma. Does not significantly enter ascitic fluid. Approximately 20-30% bound to plasma proteins.
代謝
Metabolized slightly.
消失
Primary method of elimination is renal excretion (both glomerular filtration and tubular secretion). Dosage adjustments are required in significant renal disease.
過剰投与
Acute Toxicity: In dogs, the acute toxic dose after IV administration is reported to be 0.177 mg/kg.
Treatment of Toxicity:
- Chronic Toxicity: Often resolves by temporarily stopping the drug and reevaluating the dosage regimen.
- Acute Ingestion: If recent and no cardiotoxic/neurologic signs are present, empty the stomach followed by activated charcoal. Repeated charcoal administration may be beneficial due to enterohepatic recirculation. Anion-exchange resins (colestipol, cholestyramine) can reduce absorption but are rarely available.
- Supportive Care: Continuous ECG monitoring, correct acid-base/hypoxia/fluid/electrolyte imbalances. Note: Potassium use in normokalemic patients is controversial and requires expertise.
- Antiarrhythmics: Lidocaine and phenytoin are commonly used for life-threatening digitalis-induced arrhythmias. Atropine may treat sinus bradycardia, SA arrest, or AV block.
- Antidote: Digoxin immune Fab (ovine antibodies) binds directly to the drug, inactivating it. It is highly effective but very expensive, and veterinary experience is limited.
製品
製剤
- Injection
- Tablets
- Oral Solution
- 62.5 μg oral tablet
- 125 μg oral tablet
- 250 μg oral tablet
- 50 μg/ml oral elixir
- 250 μg/ml injectable
動物用医薬品
- Veterinary-labeled products are no longer available commercially in the USA.
ヒト用医薬品
- Digoxin Solution for Injection: 250 micrograms/mL (0.25 mg/mL) and 100 micrograms/mL (0.1 mg/mL) (Lanoxin, generic)
- Digoxin Oral Tablets: 125 micrograms (0.125 mg) and 250 micrograms (0.25 mg) (Lanoxin, generic)
- Digoxin Oral Solution: 50 micrograms/mL (0.05 mg/mL) (generic)
- Lanoxin 62.5 μg, 125 μg, 250 μg tablets
- Lanoxin PG 50 μg/ml elixir
- Lanoxin 250 μg/ml injectable
規制ステータス
POM
POM-V / POM
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Store tablets, capsules, elixir, and injection at room temperature (15-30°C) and protect from light. Stable at pH 5-8; hydrolyzed in solutions with a pH of less than 3.
飼主向け情報
ジゴキシンは、心臓のポンプ機能を助け、不規則な心拍をコントロールするために使用される強力な心臓薬です。
- 厳密な投薬： 処方された通りに正確に投薬してください。有効量と中毒量の差が非常に小さいため、獣医師に相談せずに用量を変更したり、投薬を中止したりしないでください。
- 中毒症状に注意： ペットに中毒の兆候（通常は胃腸の不調から始まります）が見られた場合は、すぐに獣医師に連絡してください。食欲不振、嘔吐、下痢、無気力、気分の落ち込み、行動の変化に注意してください。
- 投薬を忘れた場合： 投薬を忘れた場合でも、次回の投薬時に2回分を与えないでください。次の予定時刻に通常の1回分を与えてください。
- 定期的なモニタリング： 薬の量が安全で効果的であることを確認するため、血液中のジゴキシン濃度、腎機能、電解質レベルをチェックする定期的な血液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。