Alpha One and Beta Receptor Blockers

Overview

• Drug Class: Affects both alpha one and beta receptors.
• Mechanism of Action:
  • Acts in the periphery (heart and blood vessels).
  • Non-selective receptor blocker affecting:
    • Alpha One: Works on arterials stimulated by epinephrine/norepinephrine.
    • Beta One: Receptors in the heart.
    • Beta Two: Receptors in the lungs, causing smooth muscle relaxation.
  • Decreases myocardial contractility (negative inotrope).

Therapeutic Effects

• Decrease progression of heart failure.
• Decrease blood pressure:
  • Reduced constriction and resistance.
  • Decrease afterload.
• Decrease heart rate (negative chronotrope):
  • Decreased SA node firing.

Indications

• Heart failure.
• High blood pressure.
• Angina (chest pain).

Precautions

• Concurrent use of multiple blood pressure-affecting drugs due to increased hypotensive effects.
• Patients with pulmonary disease, heart failure, cardiac dysrhythmias, particularly bradycardia.
• May mask hypoglycemia symptoms, especially due to beta adrenergic component.

Contraindications

• Pulmonary disease, especially asthma, due to bronchoconstriction.
• Some cardiac dysrhythmias.

Adverse Effects

• Heart failure.
• Cardiac dysrhythmias.
• Bronchospasms and bronchoconstriction:
  • Symptoms include dyspnea and wheezing.
• Fatigue, depression, and impotence.

Nursing Actions

• Assess heart rate and blood pressure.
• Perform cardiopulmonary assessment to check for worsening heart failure.
• Educate patients on:
  • Drug side effects, monitoring heart rate and blood pressure at home.
  • Recognizing hypotensive and hypertensive symptoms.
  • Effects on renal function, general side effects, and symptoms.
  • Monitoring blood glucose levels due to potential masking of hypoglycemia.

Example Drug

• Carvedilol