IHD - CSAP drug therapy - Beta-blockers

Question 1

Mechanism of action

Answer 1

Reduce myocardial oxygen demand by inhibiting the increases in heart rate, arterial pressure, and myocardial contractility caused by adrenergic activation

Question 2

Beta blockade reduces HR, MAP and myocardial contractility most strikingly during ____ [rest/exercise] but causes only small reductions at ____ [rest/exercise]

Answer 2

• Exercise
• Rest

Question 3

Therapeutic aims of beta-blockers

Answer 3

• Relief of angina and ischemia
• Reduce mortality and reinfarction rates in patients after MI
• Moderately effective antihypertensive agents

Question 4

Relative contraindications

Answer 4

• Asthma and reversible airway obstruction in patients with COPD
• AV conduction disturbances
• Severe bradycardia
• Raynaud’s phenomenon
• A history of mental depression

Question 5

Side effects

Answer 5

• Fatigue
• Reduced exercise tolerance
• Nightmares
• Impotence
• Cold extremities
• Intermittent claudication
• Bradycardia (sometimes severe)
• Impaired AV conduction
• LV failure
• Bronchial asthma
• Worsening claudication
• Intensification of the hypoglycemia produced by oral hypoglycemic agents and insulin

Question 6

If discontinuation of beta-blocker is necessary, how must it be done and why?

Answer 6

Since sudden discontinuation can intensify ischemia, the doses should be tapered over 2 weeks