====== Nifedipine ======

Nifedipine is a [[cardio:ccb:dhp|Dihydropyridine Calcium Channel Blocker]] (DHP CCB).

It primarily causes arterial vasodilation and reduces systemic vascular resistance.

Used in:

  * [[cardio:hypertension:start|Hypertension]]
  * [[cardio:angina:start|Stable Angina]]
  * Vasospastic angina
  * Raynaud phenomenon

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

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

Nifedipine blocks L-type calcium channels in vascular smooth muscle.

This leads to:

  * ↓ Intracellular calcium
  * Arterial vasodilation
  * ↓ Systemic Vascular Resistance
  * ↓ Afterload

Minimal direct effect on:

  * SA node
  * AV node
  * Myocardial contractility

Primary action = vascular.

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===== Immediate-Release vs Extended-Release =====

Immediate-Release (short-acting):

  * Rapid vasodilation
  * Reflex tachycardia
  * Not recommended for chronic hypertension
  * Associated with increased risk of adverse cardiac events

Extended-Release (preferred):

  * Smooth 24-hour BP control
  * Lower risk of reflex tachycardia
  * Appropriate for chronic hypertension and angina

Extended-release formulations are standard in modern practice.

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

  * ↓ Blood pressure
  * ↓ Afterload
  * Possible reflex tachycardia (especially short-acting form)

Does NOT significantly:

  * Slow heart rate
  * Depress AV conduction

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

Hypertension:

  * Extended-release formulation preferred
  * Often combined with:
      * [[cardio:raas:acei|ACE Inhibitors]]
      * [[cardio:raas:arb|ARBs]]
      * [[cardio:diuretics:thiazide:start|Thiazide Diuretics]]

Angina:

  * Reduces afterload
  * Improves oxygen supply-demand balance

Vasospastic Angina:

  * Coronary vasodilation

Raynaud Phenomenon:

  * Reduces vasospasm

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

Common:

  * Peripheral edema
  * Flushing
  * Headache
  * Reflex tachycardia (short-acting)

Mechanism of edema:

  * Arteriolar dilation without venodilation
  * Increased capillary hydrostatic pressure

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===== Contraindications & Cautions =====

Avoid short-acting formulation in:

  * Unstable angina
  * Acute coronary syndromes

Use caution in:

  * Severe hypotension

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===== Nifedipine vs Amlodipine =====

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

  * Longer half-life
  * Less reflex tachycardia
  * More gradual onset

Nifedipine:

  * Faster onset
  * Greater reflex tachycardia risk (short-acting)

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

  * DHP CCB
  * Strong arterial vasodilator
  * Use extended-release for chronic therapy
  * Avoid short-acting form in CAD
  * Causes peripheral edema
  * No AV nodal slowing

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===== Related =====

  * [[cardio:ccb:start|Calcium Channel Blockers]]
  * [[cardio:ccb:dhp|Dihydropyridines]]
  * [[cardio:ccb:amlodipine|Amlodipine]]
  * [[cardio:hypertension:start|Hypertension]]
  * [[cardio:angina:start|Anti-Anginal Therapy]]