====== Verapamil ======

Verapamil is a [[cardio:ccb:non_dhp|Non-Dihydropyridine Calcium Channel Blocker]] (Non-DHP CCB).

It primarily affects cardiac tissue and AV nodal conduction.

Used in:

  * [[cardio:arrhythmias:start|Dysrhythmias]] (rate control)
  * [[cardio:angina:start|Stable Angina]]
  * [[cardio:hypertension:start|Hypertension]]

→ [[cardio:ccb:start|Calcium Channel Blockers]]

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===== Mechanism of Action =====

Verapamil blocks L-type calcium channels in:

  * SA node
  * AV node
  * Myocardial tissue
  * Vascular smooth muscle (less than DHPs)

Effects:

  * ↓ Heart rate
  * ↓ AV nodal conduction
  * ↓ Contractility
  * Mild ↓ Afterload

Primary action = cardiac.

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===== Electrophysiologic Effects =====

Verapamil slows:

  * Phase 0 depolarization in nodal tissue
  * AV nodal conduction velocity

Prolongs:

  * PR interval

Used for:

  * Rate control in atrial fibrillation
  * SVT termination (AV nodal dependent)

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===== Hemodynamic Effects =====

  * ↓ Heart rate
  * ↓ Contractility
  * Mild vasodilation

Reduces myocardial oxygen demand by:

  * Lowering heart rate
  * Lowering contractility

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===== Clinical Use =====

Arrhythmias:

  * Rate control in AF
  * SVT (AV nodal reentry)

Angina:

  * Alternative to [[cardio:beta_blockers:start|Beta-Blockers]]
  * Useful when beta-blockers contraindicated

Hypertension:

  * Less commonly first-line
  * Useful in select patients

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===== Adverse Effects =====

Common:

  * Bradycardia
  * Hypotension
  * Constipation (classic)
  * Peripheral edema (less than DHPs)

Serious:

  * AV block
  * Worsening heart failure

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===== Contraindications =====

Avoid in:

  * [[cardio:heart_failure:start|Heart Failure with Reduced EF]]
  * High-grade AV block
  * Severe bradycardia

Avoid combination with:

  * [[cardio:beta_blockers:start|Beta-Blockers]]
    (risk of heart block)

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===== Verapamil vs DHP CCBs =====

Compared to:

  * [[cardio:ccb:amlodipine|Amlodipine]]

Verapamil:

  * Slows AV node
  * Reduces heart rate
  * Stronger cardiac effects

Amlodipine:

  * Primarily vasodilator
  * Minimal AV node effect

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===== Clinical Pearls =====

  * Non-DHP CCB
  * Slows AV node
  * Decreases contractility
  * Prolongs PR interval
  * Causes constipation
  * Avoid in HFrEF
  * Avoid with beta-blockers

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===== Related =====

  * [[cardio:ccb:start|Calcium Channel Blockers]]
  * [[cardio:ccb:non_dhp|Non-Dihydropyridines]]
  * [[cardio:ccb:diltiazem|Diltiazem]]
  * [[cardio:beta_blockers:start|Beta-Blockers]]
  * [[cardio:arrhythmias:start|Dysrhythmias]]
  * [[cardio:heart_failure:start|Heart Failure]]