1what do sns antagonists do
compete with n/ne at receptors to cause sympatholytic (inhibiting) effects
2factors affecting effect of antagonists
net effect at pre vs post synaptic receptors
selectivity for receptor subtype
compensatory reflex adjustments
3therapeutic uses of sns antagonists
HTN
angina
heart failure
migraine HA prevention
open angle glaucoma
benign prostatic hyperplasia
4types of alpha-adrenergic receptor antagonists
non-selective alpha antagonists
competitive alpha 1 antagonists
5nonselective alpha antagonists general mechanism
block a1 receptors > vasodilation > reflex inc HR
block a2 receptors > more NE release > even more tachycardia
6nonselective alpha antagonist indication
long term or acute pheochromocytoma
local anesth reversal
7brand name for LA reversal
oraverse
8nonselective alpha antagonists side effects
postural hypotension, tachycardia, arrythmia
9nonselective alpha antagonist drugs
phenoxybenzamine: irreversible so lim use
phentolamine mesylate (oraverse): 1/10 systemic dose, reversible, vasodil/absorb LA from sym tone reversal
10what is the primary influence in BP
TPR
11what does blocking alpha 1 receptor cause mainly
dropped BP due to dropped TPR
12clinical indications of alpha 1 competitive antagonists
HTN crisis and BPH
13prazosin mechanism
does not antagonize a2 at clinical dose
sm m relaxation in vascular, urinary bladder sphincter, prostate capsule
14what kind of antagonist is prazosin
alpha 1 competitive antagonist
15prazosin sfx
tachycardia, orthostatic hypotension, headache, nasal congestion
postural hypotension
16prazosin acute use
HTN crisis
17how do beta blockers vary
relative affinity for b1or b2
receptor efficacy
LA activity
18therapeutic indications of beta blockers
Hypertension
Angina pectoris
Myocardial infarction
Arrhythmias
Congestive heart failure
Glaucoma
19beta blockers used for HTN
v force and rate contraction > v TPR GRADUAL
reflex arc dissipates over time
nonselective or b1
20beta blockers for angina
v force and rate contraction > heart less strain > less O2 need
nonselect or b1
21beta blockers for arrhythmia
less catecholamine induced incs in conductivity, less serum K+
B1 or LA
22**beta blockers for congestive heart failure
less work load on heart (force and rate contr)
less ROS production > less remodeling or hypertrophy of heart
decreased risk ischemia
decrease HTN
non or b1
23**beta blocker for glaucoma
less aq. humor formation in eye
timolol
nonselective
24propranolol (inderal)
nonselective B receptor antagonist
antagonize NE by preventing B receps from transducing signal
doesn't affect normal ppl @ rest; only stress responses
tx HTN, arrhythmia and angina
25metoprolol (lopressor)
B1 selective receptor antagonist
use if avoiding: bronchoconstriction, blocking glucose prod in liver
little fx on normal or resting pts
tx: HTN
26labetalol (normodyne)
mixed a/B beta blocker; competitive antagonist but greater effects on B
tx: HTN crisis, chronic HTN that is safe to use during pregnancy
27carvedilol (coreg)
mixed a/B beta blocker; competitive antag but greater effects on B
tx: chronic HTN, congestive heart failure (better than metoprolol)
28sfx of beta blockers
supersensitivity: rebound HTN if sudden withdrawal
CNS: nightmares, mental depression, insomnia
potentiation of vasoconstrictors (a1 agonists)
29special pt popu to caution with beta blockers
asthma or bronchospasms pt: blockade of pulmonary B2 receptors; B1 selective preferred
diabetes: compensatory hyperglycemia is removed if B2 blocked in liver; B1 selective preferred
congestive heart failures: contraindicated with late stage
raynauds: induce or worsen