Calcium Channel Blockers

Definition

Calcium Channel Blockers (CCBs) inhibit calcium influx into vascular smooth muscle and cardiac cells. This causes vasodilation, lower blood pressure, reduced cardiac contractility, and slowed AV conduction. They are used for hypertension, angina, arrhythmias, and Raynaud's.

Classes

• Dihydropyridines (end in '-dipine'): Amlodipine, nifedipine, nicardipine. More vascular; little cardiac effect. Used primarily for hypertension.
• Non-dihydropyridines: Diltiazem, verapamil. Both vascular and cardiac effects. Used for rate control in atrial fibrillation and angina.

Side Effects

• Dihydropyridines: Peripheral edema (especially amlodipine), flushing, headache, reflex tachycardia.
• Non-dihydropyridines: Bradycardia, heart block, constipation (verapamil), heart failure exacerbation.

Contraindications

• Heart block (non-dihydropyridines)
• Severe heart failure (non-dihydropyridines)
• Cardiogenic shock

Nursing Considerations

• Check BP and pulse before administration; hold for hypotension or bradycardia per parameters.
• Teach patients to rise slowly (orthostatic hypotension).
• Avoid grapefruit juice (increases CCB levels via CYP3A4 inhibition).
• Do NOT combine non-dihydropyridines with beta-blockers (additive AV block).
• Monitor for edema and signs of heart failure.

NCLEX Relevance

Grapefruit juice interaction and hold parameters are high-yield teaching.