Beta blockers Flashcards
What are non selective beta Adrenergic receptor agonists?
Nadolol
Propranolol
Timolol
Dilator
What are beta1 selective beta Adrenergic receptor agonists?
Atenolol
Bisoprolol
Metoprolol
What are non selective beta Adrenergic receptor agonists?
Carvedilol
Labetalol
What are beta 1 selective 3rd generations agonist?
Nebivolol
Beta blockers have what suffix
O lol
What is the clinical relevance of Beta 1 receptors?
Heart: rate, contractility, automaticity, conduction velocity,
Kidney: Renin release
What is the clinical relevance of beta 2 receptors?
Lung: Bronchorelaxation
Skeletal muscle: Vasodilation, Glycogenolysis
Liver: glycogenolysis and gluconeogenesis
What are primary mechanisms of beta agonists?
Specifically block beta 1 Adrenergic receptors
They have varying affinity for beta1 and Beta2
None are specific to beta1 in a dose related way
What are the secondary mechanisms for beta 1 agonists?
Partial agonists/ intrinsic sympathomimetic activity (ISA)
They inhibit beta receptors when with catecholamines
Local anesthetic
Alpha1 blockers
Vasodilation or antioxidants
What are the effects of beta blockers on the cardiovascular system?
Decreases most of the sumpathetically supported cardiac functions.
Depends on sympathetic nervous system.
Lowers BP in hypertension
Decreased cardiac output
See slide 10 about NE release and know mechanism
See slide 10 about NE release
How do beta blockers affect the eye?
Reduced intraocular pressure
*chronic open angle glaucoma
Beta 2 receptors are on ciliary epithelium
What are the adverse effects of beta blockers on the heart?
May cause or exacerbate heart failure.
Bradyarrhythmias
Exacerbate peripheral vascular disease ( Raynauds)
Abrupt discontinuation can cause sudden death)
Exercise intolerance
What are the adverse effects of beta blockers on the pulmonary system?
Block beta 2 receptors in the bronchial smooth muscle: COPD patients can have life threatening Vasoconstriction.
Less likely with Beta 1 or Beta agonists with ISA
What are the adverse effects of beta blockers on CNS?
Fatigue
Sleep disturbance
Depression
What are the adverse effects of beta blockers on metabolism?
Delays recovery from hypoglycemia
Beta2- mediated effects of catecholamines on gluconeogenesis and gluconeogenesis.
Beta1 selective agonist no issue
Blunts the perception of symptoms of hypoglycemia.
Non-selective beta blockers first generation:
Propranolol( Prototype)
Nadolol
Timolol
Sotalol
What are the mechanics of non-selective beta blockers 1st generation propanolol prototype:
Competitive reversible antagonist of B1 and B2 receptors.
Rapid and completely absorbed
Substantial first pass metabolism
What are the clinical uses of non-selective first generation beta blockers? Propanolol prototype
Hypertension
Angina
Cardiac Arrhythmias
Myocardial infarction
Pheochromocytoma
Migraine prophylaxis
What are the adverse effects of nonselective first generation beta blockers propanolol protype
Acute heart failure Bradycardia Bronchospasm Blunt recognition hypoglycemia Abrupt withdrawal
What is Timolol?
A nonselective first generation beta blocker
Competitive and reversible antagonist of Beta 1 and 2 receptors.
Major use Glaucoma: decreases aqueous humor
Also used similarly as propanolol
What are beta 1 selective antagonists second generation:
Atenolol
Bisoprolol
Metoprolol (prototype)
What is the mechanism for beta 1 selective antagonist metoprolol?
Competitive reversible agonist of beta 1 receptors
Cardioselective
A low dose is 10 fold more selective for Beta 1
What are the clinical uses for beta 1 selective antagonist metoprolol?
Hypertension
Angina
Acute myocardial infarction
Congestive heart failure
Adverse effects: Similar to proranolol less bronchoconstriction
What is esmolol?
A beta 1 selective antagonist second generation.
Moderately selective
Half-life 8 minutes
Cleaves by esterases i tot be plasma
Prevents tachycardia in surgery
What are beta 1 antagonists with additions cardiovascular effects 3rd generation ?
Non-selective: Carvedilol and Labetolol
B1 selective: nebivolol
What are labetolol and Carvedilol
Non selective 3rd generation beta 1 antagonists:
Labetalol: competitive reversible antagonist of a1 and both beta receptors ( Hypertension)
Carvedilol: competitive reversible antagonist of Alpha 1 and beta receptors
( Antioxidant, anti inflammatory, blocks l-type calcium channels, heart failure, hypertension)
Clinical use of beta Adrenergic receptor antagonists:
Hypertension
- for under 60s and non smokers
- Beta blockers without ISA recommended for heart patients.
Ischemic heart disease:
Decreases cardiac work and reduces oxygen demand
Improves exceed use tolerance
Timolol propanolol metroprolol
Use Beta antagonist without ISA for myocardial infarction.
Cardiac arrhythmia:
Slows ventricular response rates to atrial flutter and fibrillation
Reduce ectopic beats with catecholamines
Esmolol helps with preoperative Arrhythmias
Sotatol blocks channels
Heart failure
Reducing mortality in chronic heart failure
Metroprolol bisoprolol Carvedilol
Glaucoma:
Reduces intraocular pressure
Better tolerated than Epinephrine it pilocarpine
Beta blockers that lack Logan anesthetic properties
Topical administration: Timolol betaxolol metipranolol, carteolol, metipranolol
Hyperthyroidism:
Beta blockers stop symptoms caused by increased beta tone
Palpitations tachycardia anxiety heat tolerance
Other treatments
Migraine: propanolol metoprolol Timolol
Essential tremor: propranolol
Performance anxiety: propranolol
What comorbidities should always be considered?
Beta1 selective antagonists are preferable in patients with:
Bronchospasm
Diabetes
Peripheral vascular disease
Raynaud’s phenomenon
