Adrenoreceptor ANTAGONISTS part 1 Flashcards
adrenoceptor blockers can be divided into…..
alpha blockers and beta blockers
name 2 drugs that have both alpha and beta blocking effects**
labetalol and carvedilol
name a beta 2 selective beta blocker
butoxamine
name 2 beta 1 selective beta blockers
atenolol
metoprolol
name 3 NONSELECTIVE beta blockers
propanolol
pindolol
labetolol (both alpha and beta effects)
true or false
labetolol and metoprolol have both alpha and beta blocking effects
FALSE
labetolol and carvedilol
name an alpha 2 selective blocker
yohimbine
prazosin is a __ selective blocker
a1
name 2 nonselective alpha blockers
phentolamine (reversible)
phenoxybenzamine (irreversible)
name 2 beta receptor partial agonists
labetelol and pindolol
as mentioned, labetolol and carvediolol have both alpha and beta blocking effects
explain the selectivity in more detail
b1=b2 > or equal to alpha 1> alpha 2
most selective for betas, then alpha 1, then alpha 2
name an alpha blocker that is irreversible and noncompetitive
phenoxybenamine
non selective alpha blocker that binds COVALENTLY to alpha receptors
stops catecholamine induced vasoconstriction due to tumor on adrenal gland that is releasing too much NE (phenochromocytoma)
state the effect of alpha blockers in the cardiovascular system
they cause decrease in heart rate due to vasodilation
name 2 effects of alpha blockers aside from the cardiovascular effects
nasal stuffiness (congestion)
miosis (eye constriction)
the major use of phenoxybenzamine is in treatment of _________**
pheochromocytoma
when does phenoxybenzamine have less of an effect?
when the pt is supine (laying down)
true or false
cardiac output may be increased in the administration of phenozybenzamine
true bc of reflex effects and some blocking of the a2 receptors
name some adverse effects of phenoxybenzamine
orthostatic hypotension
tachycardia
fatigue
what is phentolamine
a competitive (reversible) antagonist at BOTH ALPHA 1 AND 2 RECEPTORS****
what does reduced peripheral resistance mean
blood vessels have dilated, which increases blood flow
explain the action of phentolamine and the use
reduces peripheral resistance by blocking a1 and possibly a2
also used to treat pheochromocytoma
also used to reverse local anesthesia in soft tissue sites
name some side effects of phentolamine
severe tachycardia
arrhythmias
myocardial ischemica
what are prazosin and terazosin?
HIGHLY SELECTIVE alpha 1 blockers used to treat hypertension
besides hypertension, what else is terazosin used for
selective alpha 1 blocker
used for men with urinary retention issues due to benign prostatic hyperplasi
which has a higher bioavailability - prazosin or terazosin?
terazosin
true or false
prazosin is a nonselective alpha antagonist
FALSE
selective for alpha 1
name some clinical uses of alpha blockers
pheochromocytoma (too much NE and E)*****
urinary obstruction due to BPH – go to bathroom too much bc not getting it all out every time -***
male sexual dysfunction
chronic hypertension
hypertensive emergency when alpha agonist levels too high
peripheral vascular occlusive disease (Raynaud”s)
name drugs that can be used to treat BPH (benign prostatic hyperplasia)
ALPHA 1 BLOCKERS
terazosin
alfuzosin
doxazosin
tamsulosin
silodosin
where is b1 receptor found
the heart
where is b2 receptor found
in vasculature, bronchi
beta antagonists are used for what conditions?
hypertension
arrhythmia
angina
infarction
do beta receptor antagonists reduce or increase renin release?
REDUCE
renin causes retention of fluid and increased blood pressure. produces angiotensin which is potent pressor agent
beta blockers want to reduce BP
the antihypertensive action of beta antagonists depends on what 3 things
reduced cardiac output
decreased sympathetic activity
reduction of renin release
explain the mechanism of action of beta blockers
they competetively reduce receptor occupancy by the catecholamines and other beta agonists
BIND TO SAME SITE ON RECEPTOR - COMPETITIVE
TRUE OR FALSE
most beta blocking agents are partial agonists
FALSE - most are pure antagonists that cause NO effect of the beta receptor when it’s bound
however, SOME are partial agonists like labetolol and pindolol
name 2 beta blockers that are partial agonists and state their selectivity
labetolol and pindolol
labetolol is nonselective for neither alpha nor beta
pindolol is nonselective - binds both b1 and b2
SOME ARE ALSO INVERSE AGONISTs
NAME 2 BETA BLOCKERS THAT ARE INVERSE AGONISTS AND WHAT THIS MEANS
betaxolol and metoprolol
reduce the activity of the beta receptors below the baseline in some tissues
THEREFORE the person may get hypotension
selectivity of betaxolol and metoprolol
both are inverse agonists
both are selective for B1
name the enzyme that is a major determinant of individual differences in metoprolol plasma clearance**
CYP2D6
__ and ___ are extensively metabolized in the liver, with little unchanged drug appearing in the urine
metoprolol and propanolol
true or false
beta blockers are given chronically to lower blood pressure in patients with hypertension
these drugs usually cause hypotension in healthy individuals with normal blood pressure
FALSE
all is true except that they cause hypotension in healthy patients with normal blood pressure
besides hypotension, name 3 other uses for beta blockers
angina
chronic heart failure
following a myocardial infarction
arrhythmias
ischemic heart disease
obstructive cardiomyopathy (can increase stroke volume)
GLAUCOMA
TRUE OR FALSE
beta blockers have negative inotropic and chronotropic effects
true
CHRONIC administration of beta blockers leads to a ___ in peropheral resistance in patients with hypertension
fall
blocking the beta 2 receptors causes what?
what can you conclude from this?
may lead to airway resistance in bronchial smooth muscle, particularly in asthma patients
therefore, beta 1 selective antagonists like metoprolol and atenolol have an advantage over nonselective beta antagonists
what do beta blocking agents do to the eye?
REDUCE intraocular pressure, especially in glaucoma**
by decreased aqueous humor production
name a specific beta blocker that can be used for glaucoma
timolol eye drops
true or false
beta blockers enhance the sympathetic nervous system in the stimulation of lipolysis
FALSE – inhibit lipolysis by the sympathetic nervous system
drugs with beta adrenoceptor antagonist action generally have what kind of name?
ends with LOL
explain how nebivolol is different from the other beta antagonists
it is the MOST SELECTIVE B1 antagonist AND elicits vasodilation due to its action on endothelial nitric oxide production
true or false
metoprolol, atenolol, and other Beta 1 selective antagonists should not be used in patients with asthma
not necessarily
they can be used - definitely preferred over non selective beta antagonists, but they should be used in asthma patients with caution
benefits outweigh the risks in patients who’ve had a mycoardial infarction
name 4 beta blocking agents used for glaucoma
timolol
nadolol
levobunolol
betaxolol
Explain how beta blockers can be used in hyperthyroidism
in hyperthyroidism, there is excessive catecholamine action, ESPECIALLY in the heart
beta antagonists can be used to combat this - -namely propanolol
__________ reduces the frequency and intensity of migraines
PROPANOLOL **
Explain the discontinuation problems with beta blockers
requires dose tapering due to upregulation of beta receptors
what are some cardiovascular issues in patients taking beta blockers
reduce in heart rate and contractility and should be used cautiously in myocardial infarction patients
name 4 drugs that are selective for b1 blocking
metoprolol
atenolol
nebivolol
betaxolol
state the characteristics of metoprolol, atenolol, nebivolol, betaxolol
lower heart rate and blood pressure
reduce renin
may be safer is asthma bc selective for B1
true or false
there is no clinical indication for butoxamine
true
it is a selective B2 blocker
increases peripheral resistance and provokes asthma
name 3 drugs that block b1 AND b2
propanolol
nadolol
timolol
true or false
labetolol and pindolol have intrinsic sympathomimetic effect
TRUE
this basically just means they are partial agonists
they lower BP like other b blockers, but only slightly lower heart rate bc of partial agonist/intrinsic sympathomimetic effect
tyrosine hydroxylase inhibitor
metyrosine
helps to lower blood pressure and can be used to treat pheochromocytoma
blocks synthesis of dopamine, NE, E
