sns antag

compete with n/ne at receptors to cause sympatholytic (inhibiting) effects

net effect at pre vs post synaptic receptors
selectivity for receptor subtype
compensatory reflex adjustments

HTN
angina
heart failure
migraine HA prevention
open angle glaucoma
benign prostatic hyperplasia

non-selective alpha antagonists
competitive alpha 1 antagonists

block a1 receptors > vasodilation > reflex inc HR
block a2 receptors > more NE release > even more tachycardia

long term or acute pheochromocytoma
local anesth reversal

oraverse

postural hypotension, tachycardia, arrythmia

phenoxybenzamine: irreversible so lim use
phentolamine mesylate (oraverse): 1/10 systemic dose, reversible, vasodil/absorb LA from sym tone reversal

TPR

dropped BP due to dropped TPR

HTN crisis and BPH

does not antagonize a2 at clinical dose
sm m relaxation in vascular, urinary bladder sphincter, prostate capsule

alpha 1 competitive antagonist

tachycardia, orthostatic hypotension, headache, nasal congestion
postural hypotension

HTN crisis

relative affinity for b1or b2
receptor efficacy
LA activity

Hypertension
Angina pectoris
Myocardial infarction
Arrhythmias
Congestive heart failure
Glaucoma

v force and rate contraction > v TPR GRADUAL
reflex arc dissipates over time

nonselective or b1

v force and rate contraction > heart less strain > less O2 need

nonselect or b1

less catecholamine induced incs in conductivity, less serum K+

B1 or LA

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

less aq. humor formation in eye
timolol

nonselective

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

B1 selective receptor antagonist

use if avoiding: bronchoconstriction, blocking glucose prod in liver
little fx on normal or resting pts
tx: HTN

mixed a/B beta blocker; competitive antagonist but greater effects on B

tx: HTN crisis, chronic HTN that is safe to use during pregnancy

mixed a/B beta blocker; competitive antag but greater effects on B

tx: chronic HTN, congestive heart failure (better than metoprolol)

supersensitivity: rebound HTN if sudden withdrawal
CNS: nightmares, mental depression, insomnia
potentiation of vasoconstrictors (a1 agonists)

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