Nicardipine Drug Classification
Nicardipine is a dihydropyridine calcium channel blocker (calcium entry blocker or calcium ion antagonist) that selectively inhibits L-type calcium channels in vascular smooth muscle. 1
Pharmacological Class Structure
Nicardipine belongs to the dihydropyridine subclass of calcium channel blockers, which is one of three chemically distinct subclasses 2:
- Dihydropyridines (nicardipine, nifedipine, amlodipine) - high vascular selectivity 2
- Benzothiazepines (diltiazem) - moderate vascular selectivity 2
- Phenylalkylamines (verapamil) - least vascular selectivity 2
Mechanism of Action
Nicardipine inhibits transmembrane calcium ion influx through L-type calcium channels into cardiac muscle and smooth muscle without changing serum calcium concentrations. 1
Vascular Selectivity Profile
- High selectivity for vascular L-type calcium channels over myocardial channels 2
- Produces marked peripheral arterial vasodilation with minimal negative inotropic effects 2
- More selective for vascular smooth muscle than cardiac muscle in animal models 1
- Causes coronary and systemic vascular resistance reduction 2
Hemodynamic Effects
The dihydropyridine structure confers specific cardiovascular actions 2:
- Reduces afterload through systemic vasodilation 3
- Increases coronary blood flow through coronary vasodilation 3, 4
- Minimal effects on sinoatrial and atrioventricular conduction (unlike non-dihydropyridines) 3, 5
- May cause reflex tachycardia, especially with short-acting formulations 2
Clinical Formulations
Nicardipine is unique among dihydropyridines as the first available in both oral and stable intravenous preparations in the United States. 3, 5
Available Routes
- Oral capsules: 20 mg and 30 mg strengths 1
- Intravenous formulation: for acute cardiovascular conditions 2
Key Distinguishing Features from Other Calcium Channel Blockers
Unlike non-dihydropyridine calcium channel blockers (diltiazem and verapamil), nicardipine does NOT significantly affect: 2
- Myocardial contractility (minimal negative inotropic effect)
- Cardiac pacemaker function
- Atrioventricular conduction
- Heart rate (except reflex tachycardia from vasodilation)
This vascular selectivity makes nicardipine safer in patients with certain conduction disturbances compared to non-dihydropyridines. 3, 5
Metabolism
All calcium channel blockers, including nicardipine, are metabolized by hepatic cytochrome P450 3A4. 2