cardio:ccb:nifedipine
Nifedipine
Nifedipine is a Dihydropyridine Calcium Channel Blocker (DHP CCB).
It primarily causes arterial vasodilation and reduces systemic vascular resistance.
Used in:
- Vasospastic angina
- Raynaud phenomenon
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.
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.
Hemodynamic Effects
- ↓ Blood pressure
- ↓ Afterload
- Possible reflex tachycardia (especially short-acting form)
Does NOT significantly:
- Slow heart rate
- Depress AV conduction
Clinical Use
Hypertension:
- Extended-release formulation preferred
- Often combined with:
Angina:
- Reduces afterload
- Improves oxygen supply-demand balance
Vasospastic Angina:
- Coronary vasodilation
Raynaud Phenomenon:
- Reduces vasospasm
Adverse Effects
Common:
- Peripheral edema
- Flushing
- Headache
- Reflex tachycardia (short-acting)
Mechanism of edema:
- Arteriolar dilation without venodilation
- Increased capillary hydrostatic pressure
Contraindications & Cautions
Avoid short-acting formulation in:
- Unstable angina
- Acute coronary syndromes
Use caution in:
- Severe hypotension
Nifedipine vs Amlodipine
- Longer half-life
- Less reflex tachycardia
- More gradual onset
Nifedipine:
- Faster onset
- Greater reflex tachycardia risk (short-acting)
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
Related
cardio/ccb/nifedipine.txt · Last modified: by andrew2393cns
