What are the names of calcium channel blockers (CCBs)?

Calcium Channel Blockers (CCBs): Types and Classification

Calcium channel blockers are divided into two main structural and functional categories: dihydropyridines and non-dihydropyridines, each with distinct pharmacological properties and clinical applications. The main calcium channel blockers include dihydropyridines (amlodipine, felodipine, nifedipine, and nisoldipine) and non-dihydropyridines (diltiazem and verapamil). 1, 2

Dihydropyridine CCBs

Dihydropyridines have high selectivity for L-type calcium channels in the vasculature and produce potent peripheral vasodilation:

• Amlodipine: Used for hypertension and angina 3
• Felodipine: Dihydropyridine derivative used for hypertension 4
• Nifedipine: Potent vasodilator
• Nisoldipine: Primarily used for hypertension
• Isradipine: Binds to calcium channels with high affinity and specificity 5

Key Characteristics of Dihydropyridines:

• Potent peripheral vasodilation
• Minimal direct effects on cardiac conduction
• May cause reflex tachycardia (especially short-acting formulations)
• Higher incidence of peripheral edema (12.3%) 2
• Primary use in hypertension and angina

Non-Dihydropyridine CCBs

Non-dihydropyridines have less vascular selectivity but more pronounced effects on cardiac tissues:

• Diltiazem: Moderate to weak inhibitor of CYP3A4 1
• Verapamil: Has significant negative chronotropic and inotropic effects 1, 2

Key Characteristics of Non-Dihydropyridines:

• Significant slowing of sinoatrial and atrioventricular node conduction
• Negative chronotropic and inotropic effects
• Lower incidence of peripheral edema (3.1%) 2
• Used for hypertension, angina, and rate control in atrial fibrillation/flutter
• Should not be used in heart failure with reduced ejection fraction 2

Mechanism of Action

CCBs work by inhibiting the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle cells by blocking voltage-dependent L-type calcium channels 2, 6. This results in:

• Relaxation of arterial smooth muscle
• Decreased peripheral vascular resistance
• Reduced blood pressure
• Increased coronary blood flow
• Prevention of coronary artery spasm 2

Clinical Considerations

1. Drug Interactions:

   • Non-dihydropyridines (diltiazem and verapamil) can interact with statins, potentially increasing statin exposure 1
   • Diltiazem and verapamil should not be used with ivabradine due to risk of severe bradycardia 1

2. Contraindications:

   • Non-dihydropyridine CCBs should be avoided in heart failure with reduced ejection fraction 2
   • Use caution when combining non-dihydropyridines with beta-blockers due to potential for severe bradycardia 2

3. Side Effects:

   • Peripheral edema (more common with dihydropyridines)
   • Headache, dizziness, flushing
   • Constipation (particularly with verapamil)
   • Reflex tachycardia (with dihydropyridines) 7, 8

4. Overdose Management:

   • Calcium administration (first-line)
   • Vasopressors for hypotension
   • Atropine for significant bradycardia
   • High-dose insulin for refractory hypotension 9

The selection of a specific calcium channel blocker should be based on the patient's comorbidities, potential drug interactions, and the specific cardiovascular condition being treated 10.