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ベラパミル

Verapamil

Verapamil hydrochloride

カルシウムチャネル遮断薬 / クラスIV抗不整脈薬POIVSC犬猫小型哺乳類馬

別名: Calan · Isoptin · Verelan · Covera-HS · Securon · CP-16533-1 · D-365 · iproveratril hydrochloride · verapamili hydrochloridum

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

Initial dose of 0.05 mg/kg IV slowly, can repeat every 5 minutes up to a total dose of 0.15-0.2 mg/kg; Oral Dose: 0.5-2 mg/kg PO q8hIV/PO· q8h (for PO)
— 🐕

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
Supraventricular tachycardiaInitial dose of 0.05 mg/kg IV slowly, can repeat every 5 minutes up to a total dose of 0.15-0.2 mg/kg; Oral Dose: 0.5-2 mg/kg PO q8hIV/POq8h (for PO)—🌎 NA
Treatment of hypertension1-5 mg/kg PO q8hPOq8h—🌎 NA
Emergency treatment for hemodynamically unstable and sustained (continuous) supraventricular tachycardia0.05 mg/kg boluses IV (slowly) up to a total dose of 0.15 mg/kgIVSeries of boluses—🌎 NA
General arrhythmias1-5 mg/kg PO three times daily; 0.05-0.25 mg/kg IV slowlyPO/IVTID (for PO)—🌎 NA
Acute termination of supraventricular tachycardiaInitial dose of 0.05 mg/kg should be administered over 1-2 minutes while ECG is monitored; if not effective, may repeat in 5-10 minutes. If arrhythmia still not terminated, may give one last dose of 0.05 mg/kg (total = 0.15 mg/kg). For longer control, may give as a CRI at 2-10 micrograms/kg/minute.IVPRN / CRI—🌎 NA
Supraventricular tachyarrhythmias0.5-3 mg/kgPOq8h—🌍 EU
Supraventricular tachyarrhythmias (Acute)0.05 mg/kgIVonceover 5 minutes🌍 EU
  • Emergency treatment for hemodynamically unstable and sustained (continuous) supraventricular tachycardia: As an alternative to diltiazem
  • Acute termination of supraventricular tachycardia: Effect may persist for 30 minutes or less.
  • Supraventricular tachyarrhythmias (Acute): Administer slowly with ECG monitoring. Up to 4 repeat IV administrations at a reduced dose of 0.025 mg/kg q5min if necessary.

猫

適応用量経路頻度期間地域
Supraventricular tachycardiaInitial dose of 0.025 mg/kg IV slowly, can repeat every 5 minutes up to a total dose of 0.15-0.2 mg/kg; Oral Dose: 0.5-1 mg/kg PO q8hIV/POq8h (for PO)—🌎 NA
Supraventricular tachyarrhythmias0.5-1 mg/kgPOq8h—🌍 EU
Supraventricular tachyarrhythmias (Acute)0.025 mg/kgIVonceover 5 minutes🌍 EU
  • Supraventricular tachyarrhythmias (Acute): Administer slowly with ECG monitoring. Up to 3 repeat IV administrations q5min if necessary.

小型哺乳類

適応用量経路頻度期間地域
Cardiovascular disease0.25-0.5 mg (total dose per hamster) SCSC——🌎 NA
Cardiovascular disease8-16 mg/kg PO + 0.5-2 mg/kg SC once daily (q24h)PO/SCq24h—🌎 NA
  • Cardiovascular disease: Hamsters
  • Cardiovascular disease: Rabbits

馬

適応用量経路頻度期間地域
To control ventricular rate in atrial fibrillation0.025-0.05 mg/kg IV q 30 minutes; give less than 0.2 mg/kg total doseIVq 30 minutes—🌎 NA
  • To control ventricular rate in atrial fibrillation: ARCI UCGFS CLASS 4 DRUG

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。

診察中ですか？VetSheet の AI が薬剤・用量・投与期間を構造化された診察記録に直接記入します。VetSheet の仕組みを見る

概要

ベラパミルは​非ジヒドロピリジン系カルシウムチャネル遮断薬​であり、​クラスIV抗不整脈薬​です。

血管平滑筋に作用して血管拡張を引き起こすジヒドロピリジン系カルシウムチャネル遮断薬（アムロジピンなど）とは異なり、ベラパミルは心臓の刺激伝導系、特に房室結節（AV結節）に強い影響を与えます。

​主な臨床用途:​

  • 獣医療では主に、犬および猫の​上室性頻拍（SVT）​の管理に使用されます。
  • 心房粗動または心房細動における心室拍動数のコントロールに使用されることがあります。
  • ​臨床のポイント:​ ベラパミルは​P-糖タンパク質（P-gp）​の阻害薬として知られています。このメカニズムにより、抗てんかん薬が中枢神経系から排出されるのを防ぐ目的で、難治性てんかんの補助治療薬として研究されています。

作用機序

Verapamil exerts its effects by blocking the transmembrane influx of extracellular calcium ions through L-type voltage-gated calcium channels in myocardial cells and vascular smooth muscle cells.

  • ​Cardiac Conduction (Primary Effect):​ Blocks calcium channels in the SA and AV nodes → decreases AV node conduction velocity and increases the effective refractory period → slows ventricular response rate in supraventricular arrhythmias.
  • ​Myocardial Contractility:​ Exhibits a negative inotropic effect (decreases heart muscle contractility).
  • ​Vascular Smooth Muscle:​ Inhibits contractile mechanisms → causes vasodilation and decreases peripheral vascular resistance (though less potently than amlodipine).
  • ​Neurological:​ Inhibits ​P-glycoprotein (MDR1/ABCB1)​ at the blood-brain barrier → reduces the efflux of certain substrate drugs back into the systemic circulation.

安全性・警告

禁忌

  • Cardiogenic shock
  • Severe CHF (unless secondary to a supraventricular tachycardia amenable to verapamil)
  • Hypotension (<90 mmHg systolic)
  • Sick sinus syndrome
  • 2nd or 3rd degree AV block
  • Digoxin intoxication
  • Hypersensitivity to verapamil
  • Recent use (within a few hours) of IV beta-adrenergic blockers
  • Left ventricular dysfunction
  • Heart failure

有害事象

  • Hypotension
  • Bradycardia
  • Tachycardia
  • Exacerbation of congestive heart failure (CHF)
  • Peripheral edema
  • AV block
  • Pulmonary edema
  • Nausea
  • Constipation
  • Dizziness
  • Headache
  • Fatigue
  • Precipitation or exacerbation of congestive heart failure

注意事項

​Critical Warning:​ IV verapamil is contraindicated within a few hours of IV beta-adrenergic blocking agents (e.g., propranolol). The combination can severely depress myocardial contractility and AV node conduction, potentially causing rapid hemodynamic deterioration and ventricular fibrillation.

  • ​Cardiac Disease:​ Use with caution in patients with heart failure or hypertrophic cardiomyopathy (HCM) due to negative inotropic effects.
  • ​Organ Impairment:​ Toxicity may be potentiated in patients with hepatic or renal impairment.
  • ​Arrhythmias:​ Use very cautiously in patients with atrial fibrillation and Wolff-Parkinson-White (WPW) syndrome as fatal arrhythmias may result.
  • ​Endocrine:​ May increase blood glucose in dogs; use with caution in diabetic animals.
  • ​Breed Sensitivities:​ Verapamil is a neurotoxic substrate of P-glycoprotein. Use with extreme caution in herding breeds (e.g., Collies, Australian Shepherds) that may possess the MDR1 (ABCB1) gene mutation causing a nonfunctional P-gp protein.

医薬品相互作用

ACE Inhibitors

May cause additive hypotensive effects

Alpha-Adrenergic Blockers (e.g., prazosin)

May cause additive hypotensive effects

Beta-Adrenergic Blockers (e.g., propranolol)

May cause additive negative cardiac inotrope and chronotrope effects; IV combination is contraindicated

Doxorubicin

Verapamil may increase doxorubicin concentrations

COPP Chemotherapy

May decrease oral absorption of verapamil

Cyclosporine

Verapamil may increase cyclosporine levels

Dantrolene

Cardiovascular collapse reported in animals when used with verapamil

DigoxinMajor

Verapamil may increase blood levels of digoxin; monitoring recommended

Disopyramide

May cause additive effects and impair left ventricular function; concurrent use within 24-48 hours not recommended

Diuretics

May cause additive hypotensive effects

Erythromycin, Clarithromycin

May increase verapamil levels

Flecainide

Possible additive effects; concurrent use is to be avoided in humans

Neuromuscular Blockers

Effects of nondepolarizing muscle relaxants may be enhanced by verapamil

Phenobarbital

May reduce verapamil levels

Quinidine

Additive alpha-adrenergic blocking activity; increased hypotensive effect; verapamil can block quinidine's AV conductive effects and increase quinidine levels

Rifampin

May reduce verapamil levels

TheophyllineMajor

Verapamil may increase serum levels of theophylline and lead to toxicity

VincristineModerate

Calcium channel blockers may increase intracellular vincristine by inhibiting the drug's outflow from the cell

Beta-blockersMajor

Profound negative inotropic and chronotropic effect

Sodium-channel blockersMajor

May lead to cardiovascular depression and hypotension

Vitamin D or Calcium saltsModerate

May adversely affect verapamil activity

CimetidineModerate

May increase the effects of verapamil

DigitoxinMajor

May increase blood levels leading to potentially toxic effects

Non-depolarizing muscle relaxantsModerate

Neuromuscular blocking effects may be enhanced

監視

  • Clinical signs of toxicity (hypotension, bradycardia, edema)
  • Blood pressure (especially during acute IV therapy)
  • Serum concentration (if efficacy or toxicity warrant; 100-300 ng/mL is considered therapeutic)
  • ECG (especially during IV administration)
  • Heart rate and rhythm
  • Liver function (in patients with hepatic disease)

薬物動態

半減期

犬0.8 - 2.5 hours

吸収

Rapidly absorbed after oral administration (~90%), but undergoes a high first-pass effect in the liver, resulting in systemic bioavailability of only 20-30%. Hepatic dysfunction can significantly increase bioavailability. Food decreases the rate and extent of absorption of sustained-release tablets.

分布

Volume of distribution is approximately 4.5 L/kg in dogs. Highly protein-bound (~90% in humans). Crosses the placenta and enters milk at levels approaching plasma concentrations.

代謝

Extensively metabolized in the liver to at least 12 separate metabolites, with norverapamil being the predominant active metabolite.

消失

The majority of metabolites are excreted in the urine. Only 3-4% is excreted unchanged in the urine.

過剰投与

​Clinical Signs of Overdose:​ Bradycardia, hypotension, hyperglycemia, junctional rhythms, and 2nd or 3rd degree AV block.

​Treatment:​

  • ​Decontamination:​ If secondary to recent oral ingestion, consider gut emptying and activated charcoal administration.
  • ​Supportive Care:​ Vigorously monitor cardiac and respiratory function.
  • ​Negative Inotropy:​ Intravenous calcium salts (1 mL of 10% solution per 10 kg of body weight) may treat negative inotropic signs, but may not adequately resolve heart block.
  • ​Hypotension:​ Fluid therapy and pressor agents (e.g., dopamine, norepinephrine) may be utilized.
  • ​AV Block / Bradycardia:​ Treat with isoproterenol, norepinephrine, atropine, or cardiac pacing.
  • ​Rapid Ventricular Rate:​ Patients developing rapid ventricular rate due to antegrade conduction in flutter/fibrillation with WPW syndrome have been treated with D.C. cardioversion, lidocaine, or procainamide.

製品

製剤

  • Sustained/Extended-Release Tablets
  • Sustained/Extended-Release Capsules
  • Injection
  • Injectable: 2.5 mg/ml solution
  • Oral: 40 mg, 80 mg, 120 mg, 160 mg tablets
  • Oral: 40 mg/5 ml oral solution

動物用医薬品

  • None

ヒト用医薬品

  • Verapamil HCl Tablets: 40 mg, 80 mg & 120 mg (Calan®, generic)
  • Verapamil HCl Sustained/Extended-Release Tablets/Capsules: 100 mg, 120 mg, 180 mg, 200 mg, 240 mg, 300 mg & 360 mg (Calan® SR, Covera-HS®, Isoptin® SR, Verelan®, Verelan® PM, generic)
  • Verapamil HCl for Injection: 2.5 mg/mL in 2 mL & 4 mL vials, amps and syringes (generic)
  • Securon (2.5 mg/ml injectable)
  • Verapamil (40 mg, 80 mg, 120 mg, 160 mg tablets; 40 mg/5 ml oral solution)

規制ステータス

European Union✓ 承認済み処方箋医薬品EMA

Human authorized products used under the cascade.

United Kingdom✓ 承認済み処方箋医薬品 · POMVMD

POM (Prescription Only Medicine)

規制データなし: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Verapamil HCl tablets should be stored at room temperature (15-30°C). The injectable product should be stored at room temperature (15-30°C) and protected from light and freezing.

飼主向け情報

ベラパミルは、主に異常に速い心拍リズムを正常化するために使用される心臓の薬です。

  • ​指示通りの投薬が重要です:​ 効果を得るためには、獣医師の処方通りにすべての用量をペットに与える必要があります。用量を飛ばしたり、急に投薬を中止したりしないでください。
  • ​注意すべき症状:​ ペットが異常に無気力になったり、運動を嫌がったり、喘鳴（ゼーゼーという呼吸）、息切れ、咳を始めたり、行動や態度に急激な変化が見られた場合は、直ちに獣医師に連絡してください。
  • ​食事に関する注意:​ 食事が特定の剤形の吸収に影響を与える可能性があるため、薬を食事と一緒に与えるかどうかについては獣医師の指示に従ってください。

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。