What 3 Alpha adrenergic antagonists do we use? - Answers Phentolamine, Phenoxybenzamine,
Prazosin
What do Alpha adrenergic antagonists do? - Answers convert the vascular response to
Epinephrine from constriction to vasodilatation.
**produce vasodilation!
Alpha antagonists uses: - Answers Hypertension
Benign prostatic hyperplasia (BPH)
Pheochromocytoma
Raynaud's phenomenon
Ergot alkaloid toxicity
Where are A2 receptors found? - Answers Found periphery & on nerve terminals
**primarily presynaptic
Post-synaptic A2 receptors are found mostly in GI tract
What does A2 stimulation do? - Answers Inhibits release of norepi from nerve terminals by a
negative feedback system.
**decreases available catecholamines & Ach.
What does A2 blockade do? - Answers Increases sympathetic outflow. It promotes
norepinephrine release by eliminating negative
feedback
**increases available catecholamine
A1 antagonist selective drugs end in __________. - Answers osin (prazosin)
Which A1 antagonist is non-selective? Which is kind of selective? What does this mean? -
, Answers Selective: phentolamine
Means A1=A2
Kind of: phenoxybenzamine
means A1:A2 is 100:1
Which alpha antagonists causes least increase in HR? - Answers Selective
What 3 tranquilizer drugs have alpha blocking properties? - Answers Droperidol, haloperidol,
chlorpromazine
*all can decrease BP
What 3 ergot alkaloids have alpha blocking properties? - Answers Ergotamine, oxytocin,
methylergonovine
Alpha blockade side effects: - Answers Orthostatic Hypotension**
Tachycardia
Miosis
Nasal stuffiness
Why does alpha blockade cause nasal stuffiness? - Answers D/t unopposed vasodilatation in
mucous membranes
Should Alpha blockers be used to treat ambulatory HTN? - Answers No because they are very
potent and decrease BP rapidly
Exception: Prazosin and derivatives
What alpha antagonists are used to treat raynauds? - Answers Prazosin and derivatives
Alpha antagonists and anesthesia: - Answers All A-antagonist effects are enhanced by
anesthetic agents & strong analgesics
**they decrease BP more