Week 12: Alpha 1 Selective Antagonists, Alpha 2 Agonist Flashcards
sympathetic nervous system has what receptors
adrenergic receptors
when stimulated, flight or flight occurs (pupils constrict, vasoconstriction etc)
parasympathetic nervous system has what receptors
cholinergic receptors
anticholinergics side effects mimic what system
sympathetic nervous system
pupils dilate, dry mouth
alpha 1 selective antagonist / alpha blocker / alpha 1 adrenergic
“-zosin or osins”
doxazosin, tamsulosin, terazosin
MOA
in hypertension: inhibits alpha 1 receptors = vasodilate veins and arterioles, decreases total peripheral resistance and blood pressure
BPH: competitively inhibits alpha 1 receptors in prostatic stromal and bladder neck = reduces sympathetic tone induced urethral stricture causing sx’s
“-zosin or osins”
doxazosin, tamsulosin, terazosin
ADE
Fluid retention, nasal congestion, blurred vision, dry mouth, constipation, impotence, urinary frequency, headache, dizziness, fatigue, priapism (rare), allergic reactions (rare)
Impotence / inhibition of ejaculation
“-zosin or osins”
doxazosin, tamsulosin, terazosin
c/c
No preg/lac, volume depletion
caution HF, MI, renal, hep, elderly (beers)
“-zosin or osins”
doxazosin, tamsulosin, terazosin
pt education
SIGNIFICANT first dose orthostatic hypotension (w/in 30-90 mins) [except for tamsulosin]
take at night
if skip dose, next dose might get orthohypo
takes 4 weeks to work
alpha 2 agonist:
clonidine (Catapres) MOA & Indication
adrenergic agonist target SNS of organs/tissues; Norepeinephrine (or mimic action)
Hypertension, ADHD
HTN: stimulates alpha-2 receptors in the brain stem, = reduced sympathetic outflow from the CNS, decreasing peripheral resistance, heart rate, blood pressure and renal vascular resistance
ADHD: regulates prefrontal cortex responsible for emotions, attention, and behaviors
Down regulation of alpha 2 receptors after chronic use
clonidine (Catapres) pt education
DON’T stop abruptly (cause rapid increase in BP = life threatening!)
clonidine (Catapres) c/c
NO lac, hx of bradycardia
caution coronary insuff, renal, CVD, preg, elderly
clonidine (catapres) ADE
Drowsiness, headache, fatigue, dizziness, skin rash, xerostomia, bradycardia, nightmares, constipation, impotence
methyldopa (Aldomet) MOA and indication
antihypertensive
stimulates central alpha 2 receptors; decrease in sympathetic outflow to heart, kidneys and blood vessels
indication: hypertension
methyldopa (Aldomet) c/c
NO active liver dz/cirrhosis, hx of bradycardia, lacation
caution in coronary insuff, Cerebrovascular dz, renal impairment
NO BETA BLOCKERS! (bradycardia)
methyldopa (Aldomet) ADE
bradycardia edema sedation hypotension skin rash, myalgias, elevated LFTs, hemolytic anemia (rare), hepatotoxicity (rare)
alpha 1 receptors are located where
blood vessels, gut, bladder, prostate smooth muscle
