Calcium Channel Blockers

Introduction

• Presenter: Sarah from RegisteredNurseRN.com
• Topic: Calcium channel blockers
• Purpose: Pharmacology series; understanding calcium channel blockers for exams
• Quiz: Available after the video

Mechanism of Action

• Blocks L-type calcium channels
• Affects 3 areas:
  1. Vascular smooth muscle (coronary and peripheral arteries)
  2. Cardiac myocytes (heart muscle cells)
  3. Cardiac nodal tissue (SA and AV nodes)

Vascular Smooth Muscle

• Blocks calcium channels: Leads to relaxation/vasodilation
• Effects:
  • Decreases arterial blood pressure
  • Reduces systemic vascular resistance
  • Decreases cardiac afterload
  • Increases coronary artery blood flow
  • Prevents vasospasms

Cardiac Myocytes

• Blocks calcium channels: Weaker heart contractions
• Negative inotropic effect: Useful for angina, not for heart failure

Cardiac Nodal Tissue

• SA Node: Slows heart rate (negative chronotropic effect)
• AV Node: Slows conduction speed (negative dromotropic effect)

Uses

• Hypertension: Lowers blood pressure
• Angina: Prevents chest pain due to coronary artery spasm
• Dysrhythmias: Treats supraventricular tachycardias, atrial fibrillation

Types of Calcium Channel Blockers

1. Dihydropyridines
   • More vascular selective
   • Example: Amlodipine, felodipine, nifedipine
2. Non-Dihydropyridines
   • More heart selective
   • Example: Verapamil (phenylalkylamine), diltiazem (benzothiazepine)

Additional Conditions Treated

• Raynaud's syndrome
• Migraines
• Cerebral vessel spasms

Nursing Role and Patient Education

• Monitor heart rate: Watch for bradycardia
• Check blood pressure: Monitor for hypotension
• Teach self-monitoring: Heart rate and blood pressure
• Watch for reflex tachycardia: Caused by low blood pressure
• Educate on orthostatic hypotension: Move slowly to prevent falls
• EKG Monitoring: For dysrhythmias, especially with verapamil or diltiazem
• Signs of heart failure: Listen to lungs, check for fluid retention
• Avoid grapefruit juice: Increases drug levels
• High-fiber diet: Prevents constipation
• Oral hygiene: Prevent gingival hyperplasia
• Digoxin Monitoring: Check for digoxin toxicity
  • Signs: Nausea, vomiting, vision changes, dysrhythmias
  • Therapeutic range: 0.5 to 2 ng/mL

Conclusion

• Review of calcium channel blockers and their uses
• Importance in treating various cardiovascular conditions

Note: Always consult healthcare professionals for medical advice and treatment.