Beta-blockers Flashcards
What is the MOA of beta-blockers
Competitive inhibition of Beta-1 receptors in SA and AV node
beta receptors influence influx of calcium into myocytes
What are the different subtypes of beta-blockers
- Selective beta 1 blockers
- Non-selective beta 1 & beta 2 blockers
- Mixed beta 1/beta 2, alpha 1 blockers
1. e.g. metoprolol, 2. Nadolol, 3. carvedilol
What effects do beta-blockers have on chronotropy?
Decrease
What effects do beta-blockers have on inotropy?
Decrease
What are the hemodynamic effects of beta-blockers
Decreased HR (chronotropy)
Decreased strength of contraction (inotropy)
Beta blockers ________ myocardial oxygen demand
Decrease
True or false:
Beta blockers are indicated in treating angina
And why?
True
decrease myocardial oxygen demand
Describe how beta blockers prevent remodeling of the heart
Prevents beta 1 mediated renin release (we know that aldosterone has remodeling effects)
Also, calcium may play a role in remodling (beta blockers affect calcium concentrations in cardiac myocytes)
True or false:
Beta blockers are effective as first line monotherapy in HTN
False
Explain why non-selective beta blockers are ineffective at reducing BP
Block beta 2 receptors as well, which prevents smooth muscle relaxation
Name a selective beta blocker
beta 1 activity only
Metoprolol tartrate
Metoprolol succinate
Which formulation of metoprolol is extended release
tartrate or succinate
Succinate
Name two non-selective beta blockers
Beta 1, beta 2 activity
Nadolol
Propranolol
Name the two mixed Beta blockers
Beta 1, 2, and alpha 1 activity
Carvedilol
Labetalol
Which beta blockers are FDA approved for HF
Metoprolol Succinate
Carvedilol
Which beta blocker has the shortest half-life and is used IV
Esmolol
Which beta blocker is a first line agent for aortic dissection
Esmolol
Name a relative contraindication for beta blockers
1st degree heart block
Name an absolute contraindication for beta blockers
2nd/3rd degree heart block
Sick sinus syndrome
List some of the side effects of beta blockers
Bradycardia
Bronchospasm (in patients with asthma)
Depression (lipophilic drugs)
Mask hypoglycemia, teach pts to look for sweating
Fatigue (lipophilic drugs)
Sexual dysfunction (lipophilic drugs)
What are the three primary uses of beta-blockers?
HF
After an acute MI
Asymptomatic LV dysfunction
Where is the highest concentration of beta-1 adrenergic receptors?
Heart
Possible effect of beta-blockers on existing DMII
May precipitate or exacerbate DMII, use with caution
For their decreased chronotropic effect, who are beta-blockers recommended for?
Hyperthyroid patients
Main reason for non-adherence of beta-blockers
Sexual disfunction and impotence
Effect of beta-blockers when combined with OTC cold medicines (ex. phenylephrine)
Unopposed alpha stimulation resulting in rebound hypertension.
If clonidine when taken concurrently with beta-blockers is not tapered, what can result?
Fatal increases in hypertension
Beta-blockers are the drugs of choice in…
Exertional angina
What mechanism is caused by chronic beta-blocker use that can result in life-threatening consequences in abrupt withdrawal?
Upregulation of beta receptors over time, makes the system sensitive to SNS tone changes.
