Antihypertensive drugs part 2 Flashcards
Where are alpha 1 receptors?
arterial smooth muscle
venous smooth muscle
prostatic smooth muscle
trigone
Pazosin lowers bp?
alpha 1 receptors on arteries to cause vasodilation and decrease PVR
block the alpha receptor, prevent binding of NE or EPI
alpha 1 selective, reversible
Type of alpha 1 receptor on prostate and base of bladder?
Alpha 1 a
Alpha antagonists and their use for hypertension?
Second line drugs for chronic treatment of hypertension
not that effective as diuretic in preventing cardiovascular events and heart failure
Alpha antagonists?
Prazosin
Terazosin
Doxazosin
Chronic use of alpha blocker?
CO and plasma renin activity return to pretreatment levels
reduction in blood pressure is achieved via vasodilation induced decrease in PVR
Describe what happens when vasodilate a vein?
decrease venous return, decrease cardiac output
Describe what happens when vasodilate an artery?
decrease PVR, reflex tachy/ reflex Na and water retention– increase in CO
Besides hypertension, what else alpha blockers treat?
Benign Prostatic hyperplasia
Raynaud’s disease
Why not use tamsulosin, alfuzosin, and silodosin for hypertension?
they are more slective for alpha one in the prostate and do not affect the alpha one receptors on vascular smooth muscle
Alpha one receptor subtype found on vascular smooth m?
alpha 1 D
Raynaud’s disease?
cold precipitates vasospasm of blood vessels in fingers and toes
Use non selective alpha blockers?
Pheochromocytoma
Adrenal medulla tumor, make catecholamines (Epi, NE) increase BP
Or
Hypertensive urgencies/emergencies
non selective alpha blockers?
Phenoxybenzamine (irreversible)
Phentolamine
Adverse effects alpha antagonists?
Orthostatic hypotension from first dose effect, little during long term treatment
reflex tachycardia
edema
headache, weakness, dizziness
What antihypertensive drug will help alpha antagonist counter Na and water retention?
diuretic
Alpha and beta antagonists
Labetalol
Carvediol
Bucindolol
Labetalol MOA?
Partial agonist for beta 2, antagonist for alpha 1 and beta 1
for beta 2 partial agonist and block alpha 1 cause vasodilation on arteries
for beta 1 on the heart, cause little effect on HR and CO
Lebetalol and clin use for hypertension?
second line drug for chronic treatment of hypertension
Hypertensive urgencies/ emergencies
Side effects Lebetalol?
Bronchospasm, prolong hypoglycemia, hypotension, nausea/ vomit, orthostatic hypotension, sexual dysfunction
Centrally acting alpha 2 agonists?
Methyldopa
Clonidine
lipid soluble, work in CNS
Clonidine MOA?
alpha 2 receptors in CNS, decrease sympathetic outflow, decrease PVR/ decrease HR and CO
Clonidine and hypertension treatment?
Second line drug for chronic treatment of hypertension
transdermal patch is better tolerated
hypertensive urgencies/emergencies
Methyldopa and hypertension treatment?
Hypertension in pregnancy
Central acting alpha 2 agonists adctivate receptors in CNS?
sedation, dry mouth, depression, impotenece
more in clonidine than methyldopa
Central acting alpha 2 agonist adverse effects?
Sodium and H20 retention
transdermal clonidine contact derm
adverse effects of methyldopa?!
pos Coombs test(for autoimmune hemolytic anemia), hemolytic anemia, hepatotoxicity
Adverse effects of Clonidine?
abrupt withdrawl
rebound hypertension
nervousness, tachycardia, headache, and sweating
Direct vasodilators?
Hyradalzine
Minoxidil
Nitroprusside
Minoxidil MOA?
activate was K channels on arterial vascular smooth muscle
Hyperpolarization
Arterial smooth muscle relaxation
Hydralazine and Minoxidil Antihypertensive action?
Artery, cause vasodilation, decrease PVR, decrease BP
Decrease PVR?
increase renin, increase Ang II, increase Aldosterone, salt and water retention
Activate SNS, reflex tachycardia, increase CO
Vasoconstriction, increase BP, increase CO
Drugs to block reflex tachy and fluid retention?
diuretic and beta blocker
Hydralazine and minoxidil clinical use?
orally
chronic therapy for severe hypertension
Hydralazine clin use?
IV, hypertensive emergencies
Adverse effects Hydralazine and minoxidil?
excessive vasodilation and hypotension
Hydra- lupus like syndrome, fever, arthralgia, skin rash
Min- Hypertrchosis
Nitroprusside MOA?
Sodium nitroprusside, causes nitric oxide, increases cGMP, arterial and venous, arterial and venous vasodilation
Nitroprusside on artery and vein?
Artery- vasodilate, decrease PVR
Vein- reduced venous return
Nitroprusside clinical use?
Hypertensive emergencies titrate blood pressure, produce controlled hypotension during surgery
Nitroprusside adverse effects?
Cyanide and thiocyanate
Hypotension
End result of alpha antagonists?
chronic use, heart rate and plasma renin levels return to pretreatment levels
reduction in blood pressure is achieved via vasodilation induced decrease in PVR
