Adrenergic Blockers Flashcards
Adrenrgic antagonists are drugs which antagonize the action of what?
EP and NE at the receptor level.
Adrenergic receptors are classified according to what?
Relative affinity for alpha or beta receptors.
What drugs are non selective alpha blockers?
Phenoxybenzamine and phentolamine.
Which non selective alpha blocker is an irreversible antagonist?
Phenoxybenzamine.
Which non selective alpha blocker is reversible?
Phentolamine.
What happens when non selective alpha blockers block alpha 1 receptors?
Vasodilation and postural hypotension.
What happens when non selective alpha blockers block alpha 2 receptors?
1- reduced NE action.
2- increase release of NE, which can cause tachycardia and increased CO.
What is the mechanism of action of non selective alpha blockers?
Binds covalently (irreversibly) to alpha receptor and Blocks NA action.
Non selective alpha blockers are given through which routes?
Orally, IV, and SC injection.
What is T1/2 for phenoxybenzamine?
12 hours
What is T1/2 for phentolamine?
3 hours.
Non selective alpha blockers are use in the treatment of what?
Pheochromocytoma.
Which non selective alpha blocker is the preferred agent for the treatment of hypertensive crisis in clonidine withdrawal and cheese reaction?
Phentolamine.
What are the side effects of non selective alpha blockers?
1- postural hypotension.
2- tachycardia.
3- dizziness and headache.
4- sexual dysfunction.
List selective alpha one antagonists?
Prazosin, terazosin, and doxazosin.
What are the actions of alpha one blocker?
1- vasodilation and reduction in BP.
2- increase in HR.
3- decrease bladder sphincter tone.
4- inhibition of hypertrophy on smooth muscle of bladder neck and prostate.
prazosin and terazosin are metabolized by?
liver.
list the clinical uses of selective alpha one blockers?
1- severe hypertension.
2- benign hyperplasia of prostate.
which selective alpha one blocker is used for benign hyperplasia or prostate?
tamsulosin.
cardioselective beta antagonists block which receptor?
beta one
beta blockers lower BP but they do not induce _____
postural hypotension.
list non selective beta blockers?
1- propranolol.
2- timolol.
3- nadolol.
list selective beta one blockers?
1- acebutolol.
2- atenolol.
3- metoprolol.
4- esmolol.
5- nebivolol.
list the action of propranolol?
1- peripheral vasoconstriction.
2- bronchoconstriction.
3- reduces renin release.
4- decreased glycogenolysis and glucagon secretion.
which beta blocker readily crosses BBB?
propranolol.
list the adverse affects of propranolol?
1- bronchoconstriction.
2- metabolic disturbances (fasting hypoglycemia).
non selective beta blockers are contraindicated in what?
- bronchial asthma (due to their bronchoconstriction action).
- raynaud’s disease (by causing vasoconstriction these drugs worsen peripheral vascular disease).
when it comes to selective beta one blockers their selectivity is _____ at high doses?
lost.
selective beta one blockers are preferred in patient with?
diabetes, bronchial asthma, peripheral vascular disease.
which selective beta one blocker is used in emergency treatment of supraventricular dysrhythmias?
esmolol.
list the advantages of cardio selective beta blockers?
1- safe in asthma.
2- safe in diabetes.
3- less risk of hyperglycemia.
4- less risk of dyslipidemia.
list the mechanism of action of nadolol and timolol?
1- reduce production of aqueous humor in the eye.
2- decrease secretion of aqueous humor by ciliary body.
3- do not cause cycloplegia.
which selective beta one blocker has a very long duration of action?
nadolol
list the actions of nadolol and timolol?
1- decrease intraocular pressure.
2- more potent than propranolol.
what is the clinical use of nadolol and timolol?
chronic management of glaucoma.
