====== Diltiazem ======

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

It has both cardiac and vascular effects and is commonly used for rate control and angina.

Used in:

  * [[cardio:arrhythmias:start|Dysrhythmias]]
  * [[cardio:angina:start|Stable Angina]]
  * [[cardio:hypertension:start|Hypertension]]

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

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

Diltiazem blocks L-type calcium channels in:

  * SA node
  * AV node
  * Myocardial tissue
  * Vascular smooth muscle

Effects:

  * ↓ Heart rate
  * ↓ AV nodal conduction
  * ↓ Contractility (mild-to-moderate)
  * ↓ Afterload

Compared to [[cardio:ccb:verapamil|Verapamil]]:
  * Slightly less negative inotropy
  * More vasodilatory effect

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

Diltiazem slows:

  * AV nodal conduction
  * Nodal depolarization

Prolongs:

  * PR interval

Used for:

  * Rate control in atrial fibrillation
  * SVT management

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

  * ↓ Heart rate
  * ↓ Contractility (less than verapamil)
  * ↓ Systemic vascular resistance

Improves angina by:

  * Reducing myocardial oxygen demand
  * Mild coronary vasodilation

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

Arrhythmias:

  * Rate control in AF
  * SVT

Angina:

  * Alternative to [[cardio:beta_blockers:start|Beta-Blockers]]
  * Useful in vasospastic angina

Hypertension:

  * Secondary option
  * Particularly useful when rate control also desired

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

Common:

  * Bradycardia
  * Hypotension
  * Peripheral edema
  * Fatigue

Serious:

  * AV block
  * Worsening heart failure

Less constipation than [[cardio:ccb:verapamil|Verapamil]].

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===== Contraindications =====

Avoid in:

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

Use caution with:

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

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===== Diltiazem vs Other CCBs =====

[[cardio:ccb:verapamil|Verapamil]]:
  * Stronger cardiac suppression
  * More constipation

[[cardio:ccb:amlodipine|Amlodipine]]:
  * Pure vasodilator
  * Minimal AV nodal effect

Diltiazem:
  * Balanced cardiac + vascular effects
  * Commonly used for AF rate control

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

  * Non-DHP CCB
  * Slows AV node
  * Moderate negative inotropy
  * Useful in AF with hypertension
  * Avoid in HFrEF
  * Avoid combining with beta-blockers

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===== Related =====

  * [[cardio:ccb:start|Calcium Channel Blockers]]
  * [[cardio:ccb:non_dhp|Non-Dihydropyridines]]
  * [[cardio:ccb:verapamil|Verapamil]]
  * [[cardio:ccb:amlodipine|Amlodipine]]
  * [[cardio:arrhythmias:start|Dysrhythmias]]
  * [[cardio:heart_failure:start|Heart Failure]]