Calcium%25252525252525252520channel%25252525252525252520blockers

# Calcium Channel Blockers (CCBs) ## Overview CCBs are categorized into two main groups: **Dihydropyridines** (e.g., amlodipine, nifedipine) which primarily act as potent systemic vasodilators, and **Non-dihydropyridines** (e.g., diltiazem, verapamil) which have significant negative chronotropic and inotropic effects on the myocardium. ## Primary Indications * **Hypertension** (All) * **Angina Pectoris** (All) * **Supraventricular Tachyarrhythmias** (Non-dihydropyridines only: Diltiazem, Verapamil) * **Raynaud's Phenomenon** (Dihydropyridines) ## Adult Dosing * **Amlodipine (DHP):** 2.5–10 mg PO once daily. Max: 10 mg/day. * **Nifedipine ER (DHP):** 30–90 mg PO once daily. Max: 90 mg/day. * **Diltiazem IR:** 30–90 mg PO Q6-8H; **ER:** 120–360 mg PO daily. Max: 360 mg/day. * **Verapamil IR:** 80–120 mg PO TID; **ER:** 180–480 mg PO daily. Max: 480 mg/day. * *Note: IV Diltiazem for AFib: 0.25 mg/kg bolus, followed by 5–15 mg/hr infusion (refer to institutional protocol).* ## Pediatric Dosing *Dosing is highly variable and weight-based; always consult standardized references (e.g., Lexicomp/Harriet Lane).* * **Amlodipine:** 0.1 mg/kg/day PO (max 5 mg) initially, titrated to 0.6 mg/kg (max 10 mg). * **Diltiazem:** Often used off-label for SVT; oral dosing typically starts at 1.5–2 mg/kg/day divided TID/QID. ## Dose Adjustments * **Hepatic Impairment:** Most CCBs are extensively metabolized by the liver. Start at lower doses or avoid (especially with non-DHPs). * **Renal Impairment:** No initial dose adjustment typically required, but monitor for exacerbation of peripheral edema. ## Contraindications * **Non-DHPs (Diltiazem/Verapamil):** Acute heart failure (HFrEF), second- or third-degree AV block (without pacemaker), sick sinus syndrome, severe hypotension. * **DHPs:** Severe aortic stenosis (caution due to vasodilation), unstable angina. ## Adverse Effects * **Dihydropyridines:** Peripheral edema, reflex tachycardia, flushing, gingival hyperplasia. * **Non-dihydropyridines:** Constipation (especially Verapamil), bradycardia, heart block, myocardial depression, exacerbation of CHF. ## Key Drug Interactions * **CYP3A4 inhibitors/inducers:** Interactions with grapefruit juice, ketoconazole, clarithromycin, and rifampin drastically affect serum levels. * **Beta-blockers:** Additive bradycardia/heart block risk with non-DHPs. * **Statins:** Diltiazem/Verapamil can increase levels of simvastatin or lovastatin; limit simvastatin to 20 mg/day. ## Monitoring * **Blood Pressure:** Essential at baseline and titration. * **Heart Rate/ECG:** Mandatory for non-DHPs to monitor for bradycardia or AV nodal blockade. * **Symptoms:** Monitor for peripheral edema (DHPs) or constipation (Verapamil). * **Liver Function:** Monitor periodically in patients with chronic high-dose therapy. ## Clinical Pearls * Never use Diltiazem or Verapamil in patients with HFrEF as they increase mortality. * Nifedipine IR should never be used for acute hypertension management due to risk of unpredictable hypotension and reflex sympathetic discharge. * Dihydropyridines should be transitioned to a different class if peripheral edema becomes refractory; adding an ACE inhibitor/ARB can help attenuate DHP-induced edema. * Always verify if the prescription is for an Extended Release (ER/SR/CD/XL) formulation, as switching formulations can lead to toxicity or loss of efficacy. *** **Disclaimer:** This information is for educational purposes for healthcare professionals. Clinical practice, institutional protocols, and patient-specific factors vary. Always verify current prescribing information, package inserts, and local clinical guidelines before administering medication.