Beta-Adrenergic Antagonist (Beta Blockers)

Question 1

Selective Beta Blockers
Metoprolol, Atenolol
Indications and MOA

Answer 1

• used for HF, HTN, A Fib, angina, treatment post-acute MI
• MOA: block beta-1 receptors at SA node to decrease HR, decrease contractility in the atria and ventricles and conduction velocity, and slow conduction at AV node
• Atenolol: longer half-life than metoprolol

Question 2

Selective Beta Blockers
Metoprolol, Atenolol
Caution and Contraindications

Answer 2

• do not abruptly withdraw
• avoid in patients with bronchospasm
• avoid in patients with 2nd or 3rd AV block
• caution in peripheral vascular disease
• caution in diabetic patients (can mask symptoms of hypoglycemia)
• caution in HLD (decreases HDL, increases triglycerides and cholesterol)
• other agents preferred in pregnancy and lactation
• other agents preferred in pediatrics for HTN
• caution in elderly patients

Question 3

Selective Beta Blockers
Metoprolol, Atenolol
Adverse Drug Effects

Answer 3

• hypotension, bradycardia, dizziness, drowsiness, fatigue, insomnia, depression, pruritus, impotence, decreased libido
• anaphylactic reactions (rare)

Question 4

Nonselective Beta Blockers
Propranolol (Inderal)
Indications and MOA

Answer 4

• used for A Fib, essential tremor, migraine prophylaxis, HTN, stable angina, thyroid storm
• MOA: competitively block response to beta-1 and beta-2 stimulation, which results in decreased HR, myocardial contractility, BP, and myocardial oxygen demand

Question 5

Nonselective Beta Blockers
Propranolol (Inderal)
Caution and Contraindications

Answer 5

• do not abruptly withdraw
• avoid in patients with bronchospasm
• avoid in patients with 2nd and 3rd degree AV block
• caution in peripheral vascular disease
• caution in diabetic patients
• caution in HLD
• other agents preferred in pregnancy and lactation
• approved in pediatrics
• caution in elderly patients