アテノロール
Atenolol
Atenololum (ICI-66082)
別名: Tenormin · Atenololum · ICI-66082
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 |
|---|---|---|---|---|---|
| Cardiac arrhythmias, obstructive heart disease, hypertension, myocardial infarction, etc. | 0.3-0.6 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
| Moderate to severe sub-valvular aortic stenosis (SAS) | 0.5-1 mg/kg PO twice a day | PO | q12h | — | 🌎 NA |
| To attempt to decrease syncopal episodes associated with pulmonic stenosis | 0.25-1 mg/kg PO twice a day | PO | q12h | — | 🌎 NA |
| Hypertension | 0.25-1 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
- Cardiac arrhythmias, obstructive heart disease, hypertension, myocardial infarction, etc.: For refractory VTach combine with mexiletine (5-8 mg/kg PO q8h)
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Treatment of hypertension or cardiac conditions (e.g., hypertrophic cardiomyopathy) | 3 mg/kg PO q12h (or 6.25 -12.5 mg total dose) PO q12h | PO | q12h | — | 🌎 NA |
| Treatment of hypertension or cardiac conditions | 6.25-12.5 mg (total dose per cat) q12h | PO | q12h | — | 🌎 NA |
| Treatment of choice for hyperthyroid, hypertensive cats | 6.25-12.5 mg (total dose) PO q12-24h | PO | q12-24h | — | 🌎 NA |
- Treatment of choice for hyperthyroid, hypertensive cats: Beta-blockers are rarely sufficient alone to treat hypertension due to other causes.
フェレット
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Hypertrophic cardiomyopathy | 6.25 mg (total dose) PO once daily | PO | q24h | — | 🌎 NA |
| Hypertrophic cardiomyopathy | 3.13-6.25 mg (total dose) PO once daily | PO | q24h | — | 🌎 NA |
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
アテノロールは、主に小動物の全身性高血圧および頻脈性不整脈の管理に使用される心臓選択性β遮断薬です。肺水腫を伴わない肥大型心筋症（HCM）の猫において、動的流出路閉塞を軽減し、拡張期の心室充満を改善するためによく使用されます。
主な特徴:
- 心臓選択性: 通常の用量ではβ2受容体への作用が最小限であるため、プロプラノロールのような非選択性β遮断薬と比較して、喘息や気管支痙攣のある患者に対して比較的安全に使用できます。
- 陰性変力作用: うっ血性心不全（CHF）、腎不全、または洞不全症候群の患者には極めて慎重に使用する必要があります。
- 代謝への影響: 高用量では甲状腺機能亢進症や低血糖の臨床症状を隠蔽する可能性があります。また、高血糖または低血糖を引き起こす可能性があるため、不安定な糖尿病患者には注意が必要です。
臨床のポイント: プロプラノロールとは異なり、アテノロールは非常に水溶性が高い薬剤です。脂溶性が低いため、血液脳関門をほとんど通過せず、結果として中枢神経系（CNS）の副作用（嗜眠やうつ状態など）が著しく少なくなります。主に未変化体のまま腎臓から排泄されるため、重度の腎機能障害がある患者では用量調整が必要になる場合があります。
作用機序
Atenolol acts as a competitive, relatively specific antagonist at β1-adrenergic receptors located primarily in the myocardium.
- Pathway: Blockade of β1-receptors → decreased intracellular cAMP → reduced intracellular calcium influx.
- Cardiovascular Effects: This leads to negative chronotropic (decreased sinus heart rate) and negative inotropic (decreased contractility) effects. It slows AV conduction, diminishes cardiac output at rest and during exercise, and significantly decreases myocardial oxygen demand.
- Blood Pressure: Reduces systemic blood pressure through decreased cardiac output and potentially decreased renin release from the kidneys.
- Selectivity Loss: At higher dosages, β1 specificity may be lost, leading to β2-receptor blockade (which can cause bronchoconstriction and peripheral vasoconstriction).
- Atenolol lacks intrinsic sympathomimetic activity (ISA) and membrane-stabilizing activity.
安全性・警告
禁忌
- Overt heart failure
- Hypersensitivity to beta-blockers
- Greater than first-degree heart block
- Sinus bradycardia
- Cats with hypertrophic cardiomyopathy with accompanying pulmonary edema
有害事象
- Lethargy
- Hypotension
- Diarrhea
- Bradycardia
- Inappetence
- Depression
- Impaired AV conduction
- Worsening of heart failure
- Hypoglycemia
- Syncope
- Bronchoconstriction (rare at normal doses)
注意事項
Withdrawal Warning: Exacerbation of symptoms has been reported following abrupt cessation of beta-blockers. It is highly recommended to withdraw therapy gradually in patients who have been receiving the drug chronically.
- Renal Impairment: Use cautiously in patients with significant renal insufficiency as the drug is primarily excreted unchanged in the urine.
- Endocrine: Can mask clinical signs associated with hypoglycemia and thyrotoxicosis. Use cautiously in labile diabetic patients as it can cause hypo- or hyperglycemia.
- Cardiac: Use cautiously in patients with sinus node dysfunction. Non-specific beta-blockers are generally contraindicated in patients with CHF unless secondary to a tachyarrhythmia responsive to beta-blocker therapy.
医薬品相互作用
Additive myocardial depression may occur with concurrent use.
Concurrent use should be done with caution due to additive negative inotropic effects, particularly in patients with preexisting cardiomyopathy or CHF.
Atenolol may exacerbate rebound hypertension after stopping clonidine therapy.
May increase the hypotensive effects of atenolol.
Concurrent use may exhibit enhanced hypotensive effects.
Potential for additive effects including hypotension and bradycardia.
May have their actions blocked by atenolol, and they may in turn reduce the efficacy of atenolol.
監視
- Cardiac function
- Pulse rate
- ECG (if necessary)
- Blood pressure (if indicated)
- Signs of toxicity (lethargy, hypotension, bradycardia)
薬物動態
半減期
吸収
Absorbed rapidly. Bioavailability is approximately 90% in cats, but only 50-60% in humans.
分布
Very low protein binding (5-15%) and distributed well into most tissues. Low lipid solubility; only small amounts distribute into the CNS. Crosses the placenta and levels in milk are higher than those found in plasma.
代謝
Minimally biotransformed in the liver.
消失
40-50% is excreted unchanged in the urine and the bulk of the remainder is excreted in the feces unchanged (unabsorbed drug). Duration of beta blockade effect in cats persists for about 12 hours.
過剰投与
Common clinical signs of overdose include lethargy and vomiting. Severe overdose represents extensions of the drug's pharmacologic effects: hypotension, bradycardia, bronchospasm, cardiac failure, hypoglycemia, and hyperkalemia.
Treatment:
- If recent oral ingestion: consider emptying the gut and administering activated charcoal.
- Monitor: ECG, blood glucose, potassium, and blood pressure.
- Cardiovascular support: Symptomatic treatment. Use fluids and pressor agents (dopamine or norepinephrine) for hypotension.
- Bradycardia: Treat with atropine. If atropine fails, isoproterenol given cautiously is recommended.
- Metabolic: Insulin and dextrose may be needed for hyperkalemia and hypoglycemia.
- Advanced support: A transvenous pacemaker may be necessary. Cardiac failure can be treated with a digitalis glycoside, diuretics, and oxygen.
- Antidote: Glucagon (5-10 mg IV; human dose) may increase heart rate and blood pressure and reduce the cardiodepressant effects of atenolol.
製品
製剤
- Oral tablets
- Oral suspension (compounded)
ヒト用医薬品
- Atenolol Oral Tablets: 25 mg, 50 mg, & 100 mg; Tenormin® (AstraZeneca); generic; (Rx)
- Also available in an oral fixed dose combination product with chlorthalidone.
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
Tablets should be stored at room temperature and protected from heat, light, and moisture. Atenolol preparations are most stable at pH 4 and should be protected from ultraviolet light to prevent decomposition. Compounding Note: Atenolol oral suspensions should NOT be compounded with sugar-containing vehicles (like simple syrup), as sugars reduce potency to <90% within 7-14 days. Suspensions compounded with sugar-free vehicles (Ora-Plus/Ora-Sweet SF) retain >90% potency for 90 days at 5°C and 25°C.
飼主向け情報
- 規則正しい投薬が重要です: 効果を得るためには、獣医師の指示通りにすべての用量をペットに投与する必要があります。
- 急に投薬を中止しないでください: 獣医師に相談することなく、この薬の投与を突然中止しないでください。心拍数や血圧の危険な上昇を引き起こす可能性があります。投薬を中止する必要がある場合は、徐々に減量する必要があります。
- 副作用の観察: ペットが異常に元気がない、運動を嫌がる、息切れや咳をする、または行動や態度に急な変化が見られた場合は、すぐに獣医師に連絡してください。
- 錠剤の分割: 指示に従って、適切な用量にするために錠剤を砕いたり、1/4や半分に割ったりすることができます。
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