アムロジピン
Amlodipine
Amlodipine besylate
別名: Norvasc · Lotrel (combination) · Caduet (combination) · Amodip · Istin · Amlodipini besilas · UK-48340-26 · UK-48340-11 · Amlodipine maleate · Amlodipine besylate · Amlodipino
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 |
|---|---|---|---|---|---|
| Adjunctive therapy for refractory heart failure (advanced mitral valve degeneration as an afterload reducer) | 0.2-0.4 mg/kg PO twice daily. Initiate therapy at 0.1 mg/kg PO twice daily and up-titrate weekly while monitoring blood pressure. | PO | q12h | — | 🌎 NA |
| Arterial vasodilator for refractory CHF secondary to mitral regurgitation | 0.1 mg/kg q12-24h initially; titrate up as needed to 0.25 mg/kg PO q12-24h | PO | q12-24h | — | 🌎 NA |
| Systemic hypertension in dogs with chronic renal disease | 0.1-0.5 mg/kg PO once daily (q24h) | PO | q24h | — | 🌎 NA |
| Systemic hypertension (2nd step drug) | 0.1 mg/kg q24h; step up to 0.2 mg/kg q24h if needed | PO | q24h | — | 🌎 NA |
| Systemic hypertension | 0.05-0.1 mg/kg (titrate upwards weekly as required, up to 0.5 mg/kg) | PO | q12-24h | Long-term | 🌍 EU |
- Adjunctive therapy for refractory heart failure (advanced mitral valve degeneration as an afterload reducer): After ACE inhibitor maintenance therapy has been established.
- Arterial vasodilator for refractory CHF secondary to mitral regurgitation: Monitor blood pressure.
- Systemic hypertension in dogs with chronic renal disease: Most often combined with an ACE inhibitor. May require weeks to months to achieve satisfactory control.
- Systemic hypertension (2nd step drug): Used after enalapril/benazepril. Each step added if after 1-2 weeks systolic BP > 160 mmHg.
- Systemic hypertension: Monitor blood pressure regularly. Consider concurrent ACE inhibitor.
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Systemic hypertension (1st step drug) | 0.625 mg per cat q24h, if cat greater then 6 kg, 1.25 mg/cat q24h | PO | q24h | — | 🌎 NA |
| Systemic hypertension | 0.625-1.25 mg (total dose) PO once daily | PO | q24h | — | 🌎 NA |
| Systemic hypertension | 0.625-1.25 mg/cat | PO | q24h (may increase slowly or increase frequency to q12h if necessary) | Long-term | 🌍 EU |
- Systemic hypertension (1st step drug): Add ACE inhibitor if proteinuric.
- Systemic hypertension: Drug of choice; often successful as a single agent. Maximum effect seen within 7 days.
- Systemic hypertension: Blood pressure monitoring is essential. Appears safe even with concurrent renal failure.
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
アムロジピンはジヒドロピリジン系カルシウムチャネル拮抗薬（CCB）であり、獣医療では主に強力な末梢動脈血管拡張薬として使用されます。
- 猫の医療：猫の全身性高血圧（慢性腎臓病、甲状腺機能亢進症、肥大型心筋症などに続発することが多い）の管理において第一選択薬（ゴールドスタンダード）とされています。猫では単独投与で高い有効性を示します。
- 犬の医療：犬では、難治性うっ血性心不全（CHF）における後負荷軽減の補助薬として、または二次的な降圧薬として使用されます。犬に高用量で単独投与するとレニン・アンジオテンシン・アルドステロン系（RAAS）を活性化する可能性があるため、この作用を軽減するためにACE阻害薬（エナラプリルなど）と併用されることがよくあります。
- 臨床のポイント：作用発現が比較的緩やかであるため、急性の低血圧クリーゼを防ぐのに役立ちますが、投薬を忘れると急激なリバウンド高血圧を引き起こす可能性があります。
作用機序
Amlodipine selectively inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle by blocking L-type voltage-gated calcium channels.
- Vascular Smooth Muscle → Relaxation and vasodilation → Significant reduction in peripheral vascular resistance (afterload) → Decreased systemic blood pressure.
- It has a much higher affinity for vascular smooth muscle than cardiac muscle, meaning it produces profound vasodilation with minimal negative inotropic (contractility) or chronotropic (heart rate) effects at therapeutic doses.
- Cardiac Muscle → Mildly depresses impulse formation (automaticity) and conduction velocity.
安全性・警告
禁忌
- Patients with cardiogenic shock
- Advanced aortic stenosis (relative contraindication)
- Use with caution in patients with heart failure (due to slight negative inotropic effects)
- Use with caution in patients with hepatic dysfunction
有害事象
- Cats: Infrequent azotemia, lethargy, hypokalemia, reflex tachycardia, weight loss
- Dogs: Gingival hyperplasia (with long-term use)
- Anorexia and hypotension (early in therapy)
注意事項
Renal Considerations in Cats: There is concern that using amlodipine alone for treating hypertension in cats with renal disease may expose glomeruli to higher pressures secondary to efferent arteriolar constriction (caused by localized RAAS activation). Using an ACE inhibitor concurrently may help prevent this, though routine use of ACE inhibitors with amlodipine in cats with CKD remains somewhat controversial.
- Cardiac Disease: Use cautiously in patients with heart failure due to slight negative inotropic effects.
- Hepatic Disease: Use cautiously as the drug is extensively metabolized in the liver; half-life may be prolonged.
- Pregnancy: Fetotoxic in laboratory animals at very high doses; prolonged labor in rats. FDA Category C.
医薬品相互作用
Concomitant use may cause additive hypotension.
Concomitant use may cause additive hypotension.
Concomitant use may cause additive hypotension.
May cause hypotension if used concurrently.
May alter bioavailability of amlodipine.
May impair hepatic metabolism of amlodipine, increasing circulating levels
May impair hepatic metabolism of amlodipine, increasing circulating levels
May impair hepatic metabolism of amlodipine, increasing circulating levels
May impair hepatic metabolism of amlodipine, increasing circulating levels
CYP3A4 inducer; may reduce circulating amlodipine levels
Increased risk of hypotension when combined
監視
- Systemic blood pressure (frequent monitoring during dose titration)
- Ophthalmic exam (to assess for hypertensive retinopathy/retinal detachment)
- Renal values and electrolytes (especially if combined with ACE inhibitors)
- Clinical signs of hypotension (lethargy, weakness)
薬物動態
半減期
吸収
Slowly but almost completely absorbed after oral administration. Bioavailability is not altered by food.
分布
Very high plasma protein binding characteristics (approximately 93%).
代謝
Slowly but extensively metabolized to inactive compounds in the liver.
消失
Hepatic metabolism and subsequent excretion.
過剰投与
Overdoses pose a significant risk for profound hypotension and reflex tachycardia (though bradycardia is also possible). Common clinical signs in dogs and cats include lethargy and vomiting.
Treatment:
- When possible, massive overdoses should be managed with gut emptying (emesis/lavage) and activated charcoal.
- Provide aggressive supportive treatment (IV fluids).
- Specific therapies may include beta-agonists, intravenous lipid emulsion (ILE) therapy, and intravenous calcium to counteract the calcium channel blockade.
製品
製剤
- Oral tablets
- Oral suspension (compounded)
ヒト用医薬品
- Amlodipine Oral Tablets: 2.5 mg, 5 mg, & 10 mg (Norvasc, generic)
- Fixed-dose combination products with benazepril (Lotrel) or atorvastatin (Caduet)
規制ステータス
Amodip is approved for cats in the EU.
POM-V, POM.
規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Store tablets at room temperature in tight, light-resistant containers. Compounded oral suspensions (1 mg/mL in Ora-Plus/Ora-Sweet) retain >90% potency for 91 days at 5°C and 25°C, but must be protected from light.
飼主向け情報
- 投与方法：食事と一緒に、または空腹時に与えることができます。
- 投薬を忘れないでください：高血圧は「サイレントキラー」です。投薬を忘れると血圧が急激に上昇し、急性の失明、発作、または重篤な腎臓の損傷を引き起こす可能性があります。
- モニタリング：ペットの血圧を測定し、用量が適切であることを確認するために、定期的な通院が必要です。
- 副作用：特に投薬開始時は、無気力、脱力感、食欲不振の兆候に注意してください。犬の場合、長期使用により歯茎が肥厚する（歯肉増殖症）ことがあります。
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。