What are the commonly used calcium channel blockers for treating hypertension and arrhythmias?

Calcium Channel Blockers: Classification and Clinical Use

Calcium channel blockers are divided into two major subclasses: nondihydropyridines (verapamil and diltiazem) and dihydropyridines (amlodipine, felodipine, nifedipine, nicardipine, isradipine, nimodipine, and cilnidipine), with distinct pharmacologic properties that determine their clinical applications. 1, 2, 3

Nondihydropyridine Calcium Channel Blockers

These agents act primarily on cardiac tissue with significant effects on nodal conduction:

• Verapamil - Acts on AV nodal tissue to control supraventricular arrhythmias and rate control in atrial fibrillation/flutter 1
• Diltiazem - Similar nodal blocking properties to verapamil, effective for supraventricular tachyarrhythmias and rate control 1

Key Clinical Characteristics of Nondihydropyridines

• Both agents have negative inotropic and chronotropic effects, making them useful for arrhythmia management but potentially harmful in heart failure 1, 4
• Should not be combined with beta-blockers due to risk of profound bradycardia and AV block, particularly with verapamil 1
• Contraindicated in wide-complex tachycardias, impaired ventricular function, and heart failure 1
• Diltiazem and verapamil have important drug interactions with digoxin and cyclosporine 4

Dihydropyridine Calcium Channel Blockers

These agents have greater selectivity for vascular smooth muscle with minimal cardiac effects:

First-Generation Dihydropyridines

• Nifedipine (immediate-release formulation should be avoided due to increased mortality risk) 5, 2

Second-Generation (Long-Acting) Dihydropyridines

• Amlodipine - Preferred agent for hypertension and resistant hypertension due to superior safety profile and neutral mortality effects 5, 6, 7
• Felodipine - Similar properties to amlodipine with good tolerability 5
• Nicardipine 2
• Isradipine 2
• Nimodipine - Specifically used for vasospasm following subarachnoid hemorrhage 3
• Cilnidipine 8

Key Clinical Characteristics of Dihydropyridines

• Greater vasoselectivity with minimal AV node or sinus node effects 5
• Common side effects include peripheral edema, hypotension, reflex tachycardia, headache, and flushing 5, 4
• Do not provide survival benefit in heart failure with reduced ejection fraction, though amlodipine has neutral effects and may be used for concurrent hypertension or ischemic disease 1, 5
• Less effective than diuretics or ACE inhibitors for preventing heart failure 1

Critical Clinical Distinctions

When to Use Nondihydropyridines

• Supraventricular tachycardia (narrow-complex only) 1
• Rate control in atrial fibrillation/flutter (except pre-excited AF) 1
• Patients requiring both antihypertensive and antiarrhythmic effects 3

When to Use Dihydropyridines

• Hypertension as first-line therapy 1, 6
• Resistant hypertension (amlodipine preferred) 6
• Chronic stable angina 7
• Vasospastic angina 7
• Patients with concurrent beta-blocker therapy 1

Absolute Contraindications and Warnings

Never use calcium channel blockers in these situations:

• Pre-excited atrial fibrillation or flutter (may accelerate ventricular response) 1
• Acute heart failure with pulmonary edema 5
• Severe left ventricular dysfunction 5
• Wide-complex tachycardias (for nondihydropyridines) 1

Critical warning: Immediate-release, short-acting dihydropyridines (like immediate-release nifedipine) should never be used without concurrent beta-blockade due to increased mortality risk 5

Important Clinical Pitfalls

• Avoid combining nondihydropyridine calcium channel blockers with beta-blockers - risk of profound bradycardia and heart block 1
• Do not combine multiple calcium channel blockers simultaneously 8
• Do not use AV nodal blocking agents sequentially without considering overlapping half-lives - can cause severe bradycardia 1
• Most calcium channel blockers (except amlodipine) should be avoided in heart failure with reduced ejection fraction 1