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)
Postural hypotension May occur if you block this receptor: ________
a1
If its blocked in venous smooth muscle, and the pt stands up the BP will drop too much
Which B-blockers can be used as local anesthetics?
Acebutolol
Labetalol
Metoprolol
Pindolol
Propranolol
What do we use Tamsulosin for?
BPH. Easy to peeeee
An irreversible/non competitive antagonist will cause the dose-response curve to shift the the _______ and the max response will (decrease/stay the same)
Right
Decrease
What does yohimbine do to your body?
Blocks a2 receptors, so it will increase NE release.
BP and HR go up
(Sold as an herbal viagra)
B2 receptor stimulation has these effects:
Relax the bronchioles
Dilate blood vessels to skeletal muscle
Dilate coronary and cerebral arteries
Increase glycogenolysis
What do you need to tell your patient to do when they are starting an alpha blocker?
Take first dose at bedtime becasue it causes a HUGE drop in BP and postural hypotension for 30-90 minutes after the first dose
What is the main side effect of tamsulosin?
Ejaculation dificulty
Remember it targets the a1A subtype on the prostate
If you injected epinephrine right into the tip of your patients fingers and it starts to turn cold and white and you’re worried about necrosis, what drug is given to reverse that?
Phentolamine
What is labetalol used for?
Given IV for hypertensive Emergencies
What are the benefits of B blockers that have ISA?
May reduce risk of bronchoconstriction and bradycardia
Lipid panels stay normal
What drug is used directly in the eye to treat glaucoma, but should NOT be given to asthmatics in case they swallow a bit, since it is a non-selective B-blocker?
Timolol (Timoptic)
B1 receptors (increase/decrease) renin secretion
Increase
What will an a2 blocker cause?
Increased NE release
Increased secretion of insulin
What is the main use of Carrvedilol (Coreg)?
- hypertension
- CHF-extends life
- Post MI
Cardiologists LOVE Carvedilol!!!! One of the MOST prescribed drugs
Drugs that block a1 receptors can cause these effects:
Decrease blood pressure
Orthostatic hypotension
Miosis
Make it easier to urinate
Inhibit ejaculation
What is meant by a B-blocker having ISA (intrinsic sympathetic activity)
It has some partial agonist activity
- will stimulate the receptors when sympathetic activity is low
- but, will reduce the effects when activity is high (lots of NE and Epi floating around)
What class of drugs is often prescribed to men with BPH to help them urinate?
Alpha blocker
What drugs will increase the effect of propranolol?
Ones that inhibit P450
Cimetidine***
And chlorpromazine
What class of drugs will inhibit lipolysis, preventing you from using your fat stores for energy?
B-blockers
What kind of B blocker should you take if you would like to preserve your exercise tolerance?
B1 selective
If your pt is on a-blockers and you give them norepinephrine, what will happen?
Alpha effects will be blocked/
NE has alpha and beta effects
What kind of beta blockers will have fewer effects on your lipid panel?
B blockers with ISA (Instrinsic sympathetic activity)
What will happen if your patient is on phenoxybenzamine and you give them a SHIT TON of norepinephrine?
Nothing.
Phenoxybenzamine is irreversible and can not be overcome
What condition do we treat with Metyrosine?
Pheochromocytoma
Is it OK to give Carevedilol and Labetalol to asthmatics?
NO they are non-specific B blockers
Which receptors does Yohimbine affect?
Blocks α2 receptors
If your pateitn is on prazosin and you give them a SHIT TON of norepinephrine, what will happen?
You will see effects of NE, like increased HR and BP, since prazosin is reversible/competitive alpha antagonist
What do we use the “zosins” for?
Prazosin, terazosin, doxazosin, alfuzosin
Treating HTN
Decreases vascular resistance
A1 receptor stimulation normally produces these types of physical effects:
Vasoconstriction
Mydriasis
Decreased GI tone
Contraction of bladder sphincters
Ejaculation
(Soooo what would happen if you blocked these….)
Should you give Carvedilol to your patient with end stage CHF to extend his life?
No, do not give in end stage CHF
OK the rest of the time in CHF and post MI
What is the only beta blocker you can say is a vasoDILATOR due to it releasing NO?
Nebivolol (Bystolic)
What are the 2 reasons alpha blockers can cause reflex tachycardia?
- Decreased BP tells baroreceptors to increase sympathetic stimulation and decrease vagal tone
- If the drug also blocks a2 receptors, NE release will be increased and cause further stimulation of B receptors in the heart
What populations should you be careful giving B-blockers to?
- asthmatics
- Type I diabetics- hard to recover from hypoglycemia
Why do you still have to be cautious with asthmatics when giving B1-selective blockers?
The selectivity decreases as the dose goes up
Will an alpha blocker make it easier or harder to urinate?
Easier
Will phentolamine cause cardiac stimulation?
Yes, due to the increased NE release (a2 blockade) and the baroreceptor reflex
Why doesn’t tamsulosin cause orthostatic hypotension like all the other a blockers?
It is selective for α1A subtype !!
α1A = prostate α1B= blood vessels
What drug will Yohimbine interfere with?
Clonidine- BP will jump
Yohimbine= a2 blocker
Clonidine= a2 agonist
What does Guanethidine do?
Inhibits release of NE from nerve terminals
What drug willl decrease mortality after an MI and improve symptoms of angina
Propranolol
Decreases O2 demand
What is a side effect of labetalol (normodyne)?
Hepatotoxicity
(Maybe the reason it’s only used for hypertensive emergencies?
What does reserpine do?
Completely eliminates all of your sympathetic systems:
Depletes NE, dopamine, and serotonin
Terrible drug, not used clinically
What effect do B-blockers have on intraocular pressure?>
Decreases
-lowers the production of aqueous humor
What happens to the iris if you give an alpha blocker?
Miosis
Relaxation of the iris radial muscle
Will B-blockers stimulate/inhibit glycogenolysis?
Inhibit
If your patient is on a-blockers, what will happen if you give them phenylephrine?
Phenylephrine is a pure alpha agonist, so its effects will be totally blocked
What class of drugs is associated with a “first dose phenomenon”?
Alpha blockers:
Phentolamine
Phenoxybenzamine
Prazosin
Terazosin
Doxazosin
Alfuzosin
(NOT tamsulosin- very little effect on BP)
Which B-blocker can enter the CNS and can cause sedation?
Propranolol
It is lipid soluble
Wanna see a list of all the things propranolol does?
Decrease BP with chronic use
Decrease mortality following MI
Improves angina
Anti arrhythmic
Early CHF
lower HR for hyperthyroidism
Prevent migrainss
Decrease portal vein pressure/reduce bleeding in cirrhosis
Decrease stage fright
