Sympathomimetics - Direct-Acting Flashcards
Pure A1 agonist
Phenylephrine
not inactivated by COMT, longer duration of action than the catecholamines
Phenylephrine
effective mydriatic and decongestant, can be used to raise blood pressure
Phenylephrine
selective A1 receptor agonist
Midodrine
for orthostatic hypotension, may cause hypertension when subject is supine
Midodrine
A group of selective agonists that decrease blood pressure through actions in the CNS that reduce sympathetic tone; direct application to a blood vessel may cause vasoconstriction.
useful in treatment of hypertension
Alpha2-selective agonists
Examples of Alpha2-selective agonists
clonidine
methyldopa
guanfacine
guanabenz
Side effect of Alpha-2 selective agonists
sedation
Alpha2-selective agonists with fewer CNS side effects
moxonidine
rilmenidine
Indicated for sedation in an intensive care setting or before anesthesia
also reduces requirement of opioids in pain control
dexmedetomidine
centrally acting muscle relaxant
tizanidine
directly-acting alpha agonist used as topical congestant as it promotes constriction of the nasal mucosa
oxymetazoline
very potent B-receptor agonist and has little effect on A-receptor
a potent vasodilator
actions lead to marked increase in cardiac output associated with a fall in diastolic and mean arterial pressure and slight increase in systolic pressure
Isoproterenol
These B-selective agents increase cardiac output with less reflex tachycardia than nonselective B agonists.
less effective in activating vasodilator B2 receptors.
B1-selective agents
The isomer of dobutamine that is a potent B1 agonist and an A1-receptor antagonist.
(+) isomer
