Adrenergic Blocking Agents Flashcards
Which drug is used to treat stage fright
Propranolol
What happens to the heart when you block B receptors
Decreased HR
Decreased contractility
What happens if you take a calcium channel blocker with propranolol?
The effects are additive- you get an AV block
Will alpha blockers help you ejaculate or make it harder?
Inhibits ejacyulation
B3 receptor stimulation will have this effect
Lipolysis
What does Metyrosine (Demser) do?
It is a tyrosin analogue that blocks the rate limiting step in the synthesis of dopamine, so you can’t make NE and Epinephrine
What happens to peopel with asthma when you give them beta blockers?
They die - bronchoconstriction
A B1 selective blocker may be tolerated
What receptors are blocked by phentolamine
a1 and a2
What happens to peripheral resistance in the short term when you first start B-blockers?
Peripheral resistance increases
CO will be reduced, which will stimulate SNS activity, and skeletal muscle vasculataure will dilate due to B2 block
What happens if you abruptly stop B blockers?
Arrhythmia- your B-receptors get upregulated while you’re on the drug
B-blockers are great for reducing intraocular pressure in ppl with glaucoma, but some shouldn’t be used. Why?
Do not use the ones that cause local anesthesia in the eye- may accidentally scratch cornea and not know it
(Acebutolol, labetalol, metoprolol, pindolol, propranolol)
What are the 2 non-selective B-blockers with ISA?
Pindolol (Visken)
Carteolol (Cartol)
Do we use Guanethidine today?
No
If a receptors are blocked, _____ receptors may become dominant
B
(Especially if a drug blocks a1 and a2 since stimulation of a2 receptors normally INHIBITS NE release.) Removing this modulation will ENAHNCE the release of NE and B receptor stimulation will be more pronounced
Will you get more or less nasal congestion if you give an alpha blocker?
Increased nasal stuffiness due to vasodilation in the nasal mucosa
Metoprolol, Atenolol, and Bisoprolol will affect which receptor?
B1 only!
Decreased HR
Decreased Contractility
Decreased Renin
Decreased AV node conduction
What kind of B blocker should you take if you are an insulin dependent diabetic
B1 specific- will have less effect on glycogenolysis
What is special about esmolol (Breviblock)
VERY short acting B1 blocker
IV only
What is meant by an epinephrine reversal?
Blocking of the a receptors exposes effects of B stimulation, so you get decreased BP and increased HR
Phentolamine, prazosin, doxazosin and terazosin are (reversible/irreversible) antagonists
Reversible
What is the only B1 selective blocker that has ISA?
Acebutolol (Sectral)
If you give epinephrine and your patient is on propranolol, what will happen to their HR and Contractility?
Nothing will happen
Alpha blockers have what effect on peripheral vascular resistance
Lowers- decreases blood pressure
What is a good beta-blocker to put diurectly in your eye for glaucoma treatment and will be safer for asthmatics?
Betaxolol (Betoptic)
The effect of an adrenergic blocker depends on the _________ of the tissue and the _______ of the drug
Prevailing adrenergic tone
Selectivity for α and β receptors
What drugs are used for pheochromocytoma?
Phenoxybenzamine (long term blocking of epinephrine)
Phentolamine- hypertensive crisis
Phenoxybenzamine is (long/short) acting
Very long- it’s an irreversible alpha blockade
A competitive antagonist will shift the dose response curve to the _________ and the maximum effect (stays the same/decrease)
Right,
Stays the same
Stimulation of a2 receptors will cause:
Decreased NE
Decreased insulin
(So what would happen if you blocked these receptors?)
If your patient is on phentolamine, what happens to the HR and BP if you give them Epinephrine?
The a-blocker allows the B2 vasodilation effect of epinephrine to be dominant, so that BP is decreased, rather than increased.
Effects of epinephrine now resemble isoproterenol
Phenoxybenzamine is the only (reversible/irreversible) alpha antagonist
Irreversible
Which 2 drugs will block B1, B2, and a1 receptors?
Carvedilol (Coreg)
Labetalol (Normodyne)