Beta Blockers

Beta Blockers

• Beta blockers end with the suffix olol.
• Classified as beta adrenergic blockers or antagonists.
• They block the effects of adrenaline (epinephrine) and norepinephrine.

Mechanism of Action

• Beta 1 Receptors: Primarily found on the heart's surface.
• Beta 2 Receptors: Primarily found on smooth muscles of bronchioles and blood vessels.
• Cardioselective Beta Blockers:
  • Target beta 1 receptors in the heart's electrical conduction system.
  • Decrease heart rate (negative chronotrope effect).
• Non-selective Beta Blockers:
  • Affect both beta 1 (heart) and beta 2 (lungs) receptors.
  • Can cause vasodilation and bronchial constriction.

Therapeutic Effects

• Decrease in blood pressure and heart rate.
• Decrease in myocardial contractility (negative inotrope effect).
• Decrease in oxygen demand of myocardial cells.

Indications

• Hypertension (high blood pressure).
• Angina (chest pain).
• Dysrhythmias (abnormal cardiac rhythms).
• Left ventricular systolic function improvement.

Precautions and Contraindications

• Caution when used with other blood pressure medications.
• Non-selective blockers can affect pulmonary diseases.
• Potential contraindications include:
  • Pulmonary diseases.
  • Cardiac dysrhythmias like bradycardia.
• May mask symptoms of hypoglycemia.

Side Effects

• Congestive heart failure.
• Bradycardia (slow heart rate).
• Bronchospasms, especially with non-selective blockers.
• Fatigue, depression, and impotence.

Nursing Actions

• Assess blood pressure and heart rate before administration.
• Monitor pulmonary status and listen to breath sounds.
• Educate patients on monitoring their heart rate and blood pressure.
• Watch for potential renal function impact and blunted hypoglycemic symptoms.

Examples of Beta Blockers

• Propranolol: Non-selective beta blocker.
• Metoprolol and Atenolol: Selective beta blockers targeting beta 1 receptors.

Additional Notes

• Educate patients on recognizing side effects and the importance of regular monitoring.
• Remember that the key differentiation between these medications is their selectivity and the receptors they target.