Adrenergic Blockers Flashcards
What are the 3 drug groups in adrenergic blockers?
- Alpha blockers
- Beta blockers
- Alpha plus beta blockers
how do we categorize alpha blockers?
irreversible and reversible
give an example of a irreversible blocker?
what do irreversible blockers do?
Phenoxybenzamine
insurmountable blockade of alpha receptors, forms covalent bond with receptors
what is phenoxybenzamine?
a Non selective α 1 & α 2
what is an example of a nonselective reversible alpha blocker?
what is an example of a alpha 1 selective reversible alpha blocker?
what is an example of a alpha 2 selective reversible alpha blocker?
- Phentolamine
- Prazosin, Tamsulosin
- Yohimbine
What are the Pharmacological effects of alpha blockers in the Cardiovascular system?
CVS effects: lowering of peripheral vascular resistance and blood pressure.
They convert a pressor response of epinephrine to a depressor response- called as epinephrine reversal
They cause orthostatic hypotension and reflex tachycardia , especially with nonselective blockers due to increased release of NE (due to α2 blockade)
What are the Pharmacological effects of alpha blockers in the urinary bladder?
α1 receptprs are expressed in base of bladder and prostate, and their blockade decreases resistance to the flow of urine
what is a good treatment for benign prostatic hyperplasia?
what is a specific type of the aforementioned durg?
Selective α1 blockers
αlpha 1A subtype may be the most important subtype mediating prostate smooth muscle contraction.
Name a specific αlpha 1a antagonist (blocker) that has the greatest potency?
Tamsulosin
what alpha blockers is used in the treatment of pheochromocytoma?
Phenoxybenzamine
Phentolamine
what alpha blockers is used in the treatment of essential hypertension?
Prazosin
what alpha blockers is used in the treatment of HT due to clonidine withdrawal or cheese reaction?
phentolamine
what alpha blockers is used in the treatment of Peripheral vascular disease-Raynaud’s Phenomenon?
Calcium channel blockers are preferred
what alpha blockers is used in the treatment of Benign Prostatic Hyperplasia?
Selective α1 blockers: Prazosin, terazosin
α1a blocker: Tamsulosin or Terazosin
What will activation of αlpha 1antagonist receptors in bladder trigone, prostrate and prostatic urethra do?
increases smooth muscle tone
What do alpha 1 antagonist do in benign prostatic hyperplasia?
DO NOT reverse the hyperplasia - offers only symptomatic relief (Increases urinary flow rate-more)
what will Toxicity of α blockers present as?
- Orthostatic hypotension
- Reflex tachycardia with nonselective blockers
- Tachycardia is less common with α1 selective blockers
Beta adrenergic Blockers are all what?
Beta adrenergic Blockers Types are classified how?
All are compititive antagonists at beta adrenoceptors
Receptor Selectivity, Partial Agonist Activity or “intrinsic sympathomimetic activity(ISA)”, Local Anesthetic Activity (“membrane-stabilizing activity”)
Beta adrenergic Blockers Types classified by receptor selectivity are divided into 2, what are these?
- Nonselective β blockers (both β 1 and β 2)
- β 1-selective blockers (Cardioselectivity) ***
Example of Nonselective β blockers (both β 1 and β 2) are…
Nadolol, propranolol, timolol
Example of Nonselective β blockers (both β 1 and β 2) that are α and β blocker as well, are…
Labetalol and carvedilol
Example of β 1-selective blockers (Cardioselectivity) are…
These are a good option to treat what?
Atenolol, Betaxolol, Esmolol, Acebutalol, Metoprolol
asthma
What are example of beta adrenergic blockers that have Partial Agonist Activity or “intrinsic sympathomimetic activity(ISA)”?
these drugs are good for treating what condition? why?
pindolol, acebutolol
is an advantage in treating patients with asthma because these drugs are less likely to cause bronchospasm.
what is an example of a beta adrenergic blocker with Local Anesthetic Activity (“membrane-stabilizing activity”)?
propranolol
what is a disadvantage of such beta blockers when used topically in the eye?
What beta adrenergic blocker drug can be used in the eye for the treatment of glaucoma?
it decreases protective reflexes and increases the risk of corneal ulceration.
Timolol
what is the effect of blockers in hypertension?
what is the effect of blockers in ischemic heart disease?
what is the effect of blockers in cardiac arrhythmia?
Which drug is used in this previous question?Why?
decrease CO and renin release
reduce the frequency of angina episodes and improve exercise tolerance. Prolongs survival in patients with myocardial infarction
increasing the AV nodal refractory period
Sotalol which has antiarrhythmic effects involving ion channel blockade in addition to its beta blocking action
what is the effect of blockers in heart failure?
Metoprolol, carvedilol can reduce mortality in chronic heart failure
what is the effect of blockers in glaucoma?
Timolol: reduced production of aqueous humor by the ciliary body, which is physiologically activated by cAMP.
what beta blocker is used in pheochromocytoma?
Labetalol
what beta blocker is used in migrane?
what beta blocker is used in performance anxiety?
Propranolol
Propranolol
What are the Side Effects of Beta Blockers?
what do you get if they are used chronically? Why?
Bradycardia
Bronchospasm*
Chronically = increased LDL and Triglycerides
- because they decrease insulin
Betablockers should be cautiously used in patients with what condition? Why?
congestive heart failure, they depresses myocardial contractility and excitability
Sudden stoppage of betablocker therapy leads to what?
rebound hypertension
