Calcium Channel Blockers - Overview

Introduction

• Presenter: Sarah from RegisteredNurseRN.com
• Topic: Calcium Channel Blockers
• Video Highlights: Quizzes available after watching
• Mnemonic: NURSE to remember key points about medications

Mechanism of Action

• Areas Affected: L-type of Calcium Channels
  • Vascular smooth muscle (coronary & peripheral arteries)
  • Cardiac myocytes
  • Cardiac nodal tissue (SA & AV nodes)

Vascular Smooth Muscle Effects

• Calcium’s Role: Facilitates contraction
• Blockage: Leads to relaxation (vasodilation)
• Results of Vasodilation:
  • Decreased Arterial Blood Pressure
  • Decreased Systemic Vascular Resistance
  • Decreased Cardiac Afterload (less workload on the heart)
  • Increased Blood Flow: To coronary arteries, preventing vasospasms
• Clinical Benefits: Treat hypertension & prevent angina, especially variant angina (Prinzmetal’s angina)

Cardiac Myocytes Effects

• Blockage of Calcium Channels: Leads to weaker heart contractions
• Negative Inotropic Effect: Decreased oxygen demand in heart muscle
• Clinical Considerations: Beneficial for angina, not recommended for heart failure

Cardiac Nodal Tissue Effects

• SA Node (Pacemaker): Slower heart rate (negative chronotropic effect)
• AV Node (Gatekeeper): Slower conduction speed (negative dromotropic effect)
• Clinical Applications: Effective for treating dysrhythmias (e.g., supraventricular tachycardia, atrial fibrillation)

Types of Calcium Channel Blockers

Dihydropyridines

• Vascular Selective: Primarily targets vascular smooth muscle
• Uses: Treat hypertension & angina
• Medications: Amlodipine, Felodipine, Nifedipine

Non-Dihydropyridines

• Myocardial Selective: Primarily targets the heart
• Uses: Treat hypertension, angina, and dysrhythmias
• Medications: Verapamil (Phenylalkylamine), Diltiazem (Benzothiazepine)
• Additional Conditions: Raynaud's syndrome, migraines, cerebral vessel spasms

Nursing Considerations, Side Effects, & Patient Education

Monitoring

• Heart Rate: Risk of bradycardia, especially with Verapamil & Diltiazem
• Blood Pressure: Risk of hypotension with all CCBs
• Reflex Tachycardia: Monitor for compensatory increase in heart rate
• Orthostatic Hypotension: Teach patients to rise slowly
• EKG: Monitor for potential dysrhythmias (e.g., first-degree AV block)
• Signs of Heart Failure: Wet lung sounds, difficulty breathing, rapid weight gain, edema

Patient Education

• Self-Monitoring: Check heart rate & blood pressure regularly, record readings
• Diet: High fiber to prevent constipation (especially with Verapamil & Diltiazem), good oral hygiene to prevent gingival hyperplasia
• Avoid Grapefruit Juice: Increases drug levels in the body
• Watch for Digoxin Toxicity: Due to potential interaction; symptoms include nausea, vomiting, vision changes, and dysrhythmias

Summary

• Mnemonic: Remember NURSE to recall key points
• Clinical Benefits: Effective in managing hypertension, angina, and certain dysrhythmias
• Nursing Role: Critical for monitoring and patient education