alpha and beta blockers + sympatholytics Flashcards
whats the function of alpha 1 receptors ?
1- effect on vessels =VASOCONSTRICTION
2- effect on uterus : Contraction
3- eyes : contraction of the dilator pupilieee ( muscle in the eye ) leading to dilated pupils and myadrasis , during sympathetic activity eyes dilate to see properly in danger
4- wall of GIT/BLADDER = dilation
5- splinchter GIT/BLADDER = contraction ( if alpha is blocked lead to urine retention )
6- sweat glands of the palm and forehead = sweating
what is the function of alpha 2 receptors?
its mainly presynaptic :
it has inhibitory effect —-> inhibit the release of noreephrine –> relaxation and vasodilation
whats the function of alpha blocker?
1- vasodilation MOST important
and the opposite of everything mentioned in the function
what reflex does do alpha blockers do?
reflex tachycardia due to hypotension because they cant reset the baroreceptor like ace and bb
what are the 2 types of alpha blockers? give examples
non selective which block both alpha 1 and alpha 2 like ( AMINE ):
phenoxybenzamine
Phentolamine
Selective alpha 1 blockers ( OSIN) :
Prazosin- PROTOTYPE
Doxazosin
Terazosin
why dont we have selective alpha 2 blockers?
cuz alpha 2 is a good receptor and it causes inhibition and relaxations
what are the uses of non selective alpha blockers? phenoxybenzamine/phentolamine
is no longer used for hypertension but it is used for PHEOCHROMACYTOMA
what are the uses of selective alpha blockers ? prazosin doxazoin terazosin
there are 3 uses :
1- HYPERTENSION
2- PHEOCHROMOCYTOMA in combination with beta blocker (b4 surgery)
3- TREATMENT OF RAYNAUD DISEASE ( which ischemia due to vasoconstriction, you give alpha blocker cuz it causes vasodilation )
whats happens when you give the first dose alpha blockers? But its resolved later when body adjusts to it
SEVERE hypotension and syncope + reflex tachycardia
what is the function of beta 1 receptors?
In heart : Increases all aspects of the heart : contractility ,cardiac output, heart rate, everything
in kidneys : Release of renin
Vessels : Vasodilation
Lipolysis
whats the function of beta 2 receptors?
نصف الرجوله b2
In skeletal muscle :
1- Vasodilation = more blood to muscles
2- Increase sensitivity of muscles
3- takes potassium from blood and take it to the muscle –> hypokalemia
In liver : glycolysis you need energy for running
in trachea : bronchodilation you need air to run
In eyes : increase the aqueous humor to increase the eye pressure –> when you are running theres pressure in your eyes the aqueous humor will counter this pressure – > beta blockers can be used in glucoma
in heart : Vasodilation of coronary arteries —> beta agonist can be used in angina and prinzemetal angina
-Utertine : relaxation -when you are running and you are pregnant you dont want to contract w gg
In CNS : release norepinephrine
whats the function of beta blockers?
the antihypertensive effects :
1- Decrease cardiac output ( due to blockage b1 decreasing heart rate )
2- decrease sympathetic flow from CNS ( Due to blockage of b2 )
3- Inhibit renin release ( due to blockage of b1)
4-increase PGI and nitiric oxide leading to vasodilation
5- reset baroreceptor no tachycardia like ACE
6-bronchoconstriction – contraindicated in asthma patients
7- inhibit glycogenlysis in liver
and opposite of everything else mentioned before
what are the types of beta blockers and give examples
non selective beta blockers block both beta 1 and beta 2 :
Propranol = the prototype
Nodalol
Timolol
pindolol
penbutalol
Cartelol
selective beta blockers block beta 1 only :
metaprolol
Atenolol
acebutalol
bisoprolol
nebivolol
whats the different functions of both types?
the none selective, block both b1 and b2 leading to:
decrease HR and contractility
decrease renin release
vasodilation
decrease cns sympathetic activity
inhibit glycogenlysis
bronchoconstriction
But the selective ones only work on heart and kidney and vessels
which beta blocker has extended period of action?
nadolol non selective
which beta blocker causes vasodilation by nitric oxide release
nebivolol selective
which beta blockers require dosage reduction in renal failure
nadolol and cartelol both are none selective
which beta blocker is used in glucoma
timolol ( non selective ) and betaxolol
which beta blockers are cardio selective
atenolol and metaprolol both are selective
which beta blocker are lipophilic and metabolized in liver
PM
proprolol and metaprolol
which beta blockers are lipophobic and excreted unchanged in urine
AS
atenolol and sotalol
what is the most selective beta blocker
nebivolol
what are the adverse effects of beta blocker?
1- hear failure cuz heart depressing
2- bradycardia no reflex tachycardia cuz they reset baroreceptor
3-heart block from depressing
4- bronchoconstriction
5- sedation
6- sudden stop , if you want to stop , stop gradually to avoid arrhythmia and hypertension
what are the contraindication of beta blocker
1- asthma patients cuz bronchoconstriction
2- prinzemetal angina ( you should beta agonist not antagonist )
3- peripheral vascular disease ( RAYNAUD FOR EXAMPLE, peripheral vascular disease means ischemia , you dont want to give bb cuz you need beta vasodilation effect )
4- alone in pheochromocytoma
be caution in diabetes patients cuz sometimes sugar drops and when bb are used it will inhibit glycogenlysis and there wont be sugar to help., this is most likely avoided when using selective cuz selective inhibit b1 alone and not b2 and b2 is responsible for glycogenlysis
how is bb administered ?
orally, iv
what are drugs that inhibit both alpha and beta receptor together
labetalol and carvedilol
how is labetalol administered
IV and orally
Labetalol is used in emergencies cuz its IV
whats the special point of labetalol and carvedilol
they can be used alone in pheochromocytoma cuz they block both a and b
is labetalol and carvedilol safe for pregnancy?
yes both can be used
what reflex does labetalol cause
it doesnt cause any reflex and not reflex tachycardia cuz its also a beta blocker and it reset baroreceptor
whats the difference between labetalol and carvedilol
carvedilol has greater b blockage effect compared to labetalol
what are centrally acting sympatholytic
drugs that are alpha 2 agonists
what are the functions of sympatholytic
they activate alpha 2 receptors in the brain which inhibit noreepinephrine and and lead to relaxation
what are the 2 examples of sympatholytics
alpha methyl dopa
clonidine
what are the adverse effects of methyl dopa
hemolytic anemia
whats the best scenario where you use clonidine/methyl
hypertension + renal failure
what is clonidine usually administered with and how its administered
its given with diuretics cuz it causes water sodium retention
its administered IV, Orally, Patch
what are the adverse effects of clonidine ?
Sedation
Drying of nasal mucosa
what happens when you stop suddenly?
rebound hypertension js like beta blockers so you must stop slowly and gradually
what do you give with vasodilators ?
diuretics and bb cuz vasodilators lead to reflex tachycardia and increased renin release + water retention
you give diuretics and to counter the water retention and bb to counter reflex tachycardia
what are the drugs safe for pregancy until now
number 1 always :-
1- ALPHA METHYL DOPA /Clonidine
2- labetalol/carvedilol
what are the drugs that can be used for emergencies until now
1- enalaprilat iv
2- labetalol IV
