Lecture Notes: Cardiovascular Drugs (Topic 6D)

Professor Hoffman

Overview

• Topic: Vasodilators, Nitrates, Antiarrhythmics, and Cardiac Glycosides
• Focus: Mechanisms, uses, reactions, nursing considerations, patient teaching.

Vasodilators

• Examples: Minoxidil, Hydralazine, Nitroprusside
• Mechanism: Act on vascular smooth muscle, causing blood pressure reduction.
• Primary Use: Hypertension
• Secondary Uses: Various
• Reactions:
  • Lowering BP too quickly (risk of hypotensive crisis)
  • Palpitations, chest pain, systemic lupus erythematosus (SLE)
  • Neurological effects (tremors, numbness, disorientation)
  • Sinus and GI tract impacts, headaches
• Nursing Considerations:
  • Monitor BP
  • Watch for signs of SLE
  • Ensure drug compliance
  • Monitor for orthostatic hypotension

Nitrates

• Specific Vasodilators: Contain "nitrate" in the generic name
• Mechanism: Quick-acting, primarily on cardiac circulation
• Uses: Angina prevention and treatment
• Reactions:
  • Hypotension, palpitations, headaches (especially with sublingual or IV nitroglycerin)
  • Weakness, sweating, dizziness from hypotension
• Nursing Considerations:
  • Monitor BP
  • Teach patients about hypotension signs
  • Advise against eating or smoking during sublingual use
  • Avoid combining with sildenafil (Viagra) due to severe BP drop risk
  • Inform patients on dosing schedules and emergency procedures

Antiarrhythmics

• Purpose: Change cardiac conduction system to stabilize heart rate
• Class I: Sodium channel blockers
  • Examples: Decrease cell responsiveness and heart rate
  • Considerations: Avoid grapefruit juice (toxicity risk), monitor sodium levels
• Class II: Beta-blockers
  • Uses: Antiarrhythmic, not just antihypertensive
• Class III: Potassium channel blockers (e.g., Amiodarone)
  • Mechanism: Slow conduction, decrease responsiveness
  • Risks: Toxicity, fatal interactions, black box warning
  • Considerations: Monitor electrolytes closely
• Class IV: Calcium channel blockers
  • Mechanism: Block calcium, slow conduction, reduce contractility
  • Nursing Considerations: Vital signs monitoring

Cardiac Glycosides

• Example: Digoxin
• Mechanism: Work on sodium-potassium pump, decrease HR but increase contractility
• Uses: Heart failure (later stages), atrial fibrillation
• Risks: Toxicity, GI symptoms, bradycardia
• Considerations:
  • Monitor dosing, digoxin, and potassium levels
  • Watch for signs of GI toxicity
  • Assess apical HR, hold dose if below parameters

Conclusion

• Next Steps: Proceed to the next topic in the series.