Calcium%25252525252525252525252525252525252525252525252525252525252525252525252520channel%25252525252525252525252525252525252525252525252525252525252525252525252520blockers

# Calcium Channel Blockers ## Overview Calcium channel blockers (CCBs) are a class of medications that reduce the influx of calcium ions into cardiac and vascular smooth muscle cells. This leads to vasodilation and decreased myocardial contractility and heart rate, depending on the specific agent. ## Primary Indications * Hypertension * Angina pectoris (stable and variant) * Supraventricular tachyarrhythmias (e.g., atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia) * Raynaud's phenomenon ## Adult Dosing Dosing varies significantly by agent and indication. Examples include: * **Dihydropyridines (e.g., amlodipine, nifedipine, felodipine):** * Amlodipine: 2.5-10 mg once daily. Max 10 mg daily. * Nifedipine (extended-release): 30-90 mg once daily. Max 120 mg daily. * **Non-dihydropyridines (e.g., verapamil, diltiazem):** * Verapamil: * Hypertension: 80-160 mg two to three times daily. Max 480 mg daily. * Angina: 40-80 mg three to four times daily. Max 480 mg daily. * Arrhythmias: Initial dose typically 40 mg IV, followed by 2.5-5 mg IV over 2 minutes, may repeat. Oral dosing varies. * Diltiazem: * Hypertension: 30-60 mg three to four times daily or 180-360 mg once daily (extended-release). Max 540 mg daily. * Angina: 30-60 mg three to four times daily or 120-360 mg once daily (extended-release). Max 540 mg daily. * Arrhythmias: Initial dose typically 20 mg IV, followed by 0.25 mg/kg IV bolus, then 5-15 mg/hr IV infusion. Oral dosing varies. ## Pediatric Dosing Pediatric dosing for CCBs is not well-established for all agents and indications. Dosing should be guided by expert consultation or specific pediatric guidelines. * **Amlodipine:** 0.1-0.3 mg/kg/day once daily (max 10 mg/day) for hypertension in children and adolescents. * **Verapamil:** May be used in pediatric patients for supraventricular tachycardias, but requires careful titration and monitoring. Dosing varies widely. ## Dose Adjustments * **Hepatic Impairment:** Reduce dose and titrate slowly due to decreased metabolism. * **Renal Impairment:** Generally no dose adjustment needed for most CCBs, but caution is advised with non-dihydropyridines. ## Contraindications * Hypersensitivity to the specific CCB. * Cardiogenic shock. * Severe hypotension. * Sick sinus syndrome or AV block greater than first-degree (without a pacemaker) for non-dihydropyridines (verapamil, diltiazem). * Acute myocardial infarction with pulmonary congestion (for non-dihydropyridines). ## Adverse Effects Common adverse effects include: * Peripheral edema * Headache * Flushing * Dizziness * Gastrointestinal upset (nausea, constipation) * Bradycardia and AV block (more common with non-dihydropyridines) * Gingival hyperplasia (prolonged use) ## Key Drug Interactions * **Beta-blockers:** Additive effects on heart rate and contractility, increasing risk of bradycardia and heart failure. * **CYP3A4 Inhibitors/Inducers:** Can alter CCB metabolism (e.g., grapefruit juice, azole antifungals, rifampin). * **Digoxin:** CCBs can increase digoxin levels. * **Statins:** Some statins (e.g., simvastatin, atorvastatin) can have increased levels when co-administered with certain CCBs. * **Grapefruit Juice:** Can significantly increase serum concentrations of amlodipine, nifedipine, verapamil, and diltiazem. ## Monitoring * Blood pressure and heart rate. * Signs of heart failure (edema, shortness of breath). * Electrocardiogram (ECG) for bradycardia or AV block, especially with non-dihydropyridines. * Renal and hepatic function. * Serum digoxin levels if co-administered. ## Clinical Pearls * Dihydropyridines are more potent vasodilators and are generally preferred for hypertension and angina without significant supraventricular arrhythmias. * Non-dihydropyridines have negative chronotropic and inotropic effects and are useful for rate control in atrial fibrillation and for angina. * Avoid short-acting nifedipine for hypertension due to risk of reflex tachycardia and precipitating angina or MI. * Non-dihydropyridines should be used with caution or avoided in patients with heart failure with reduced ejection fraction. *** *This information is intended for educational purposes and does not substitute for professional medical advice. Always consult the most current prescribing information and your healthcare provider for specific treatment decisions.*