HF
Peripherally Acting Sympatholytics
PRAZOSIN
Ischemic Heart Disease
CLONIDINE, METHYLDOPA
Andrenergic Antagonists: beta-blockers (class II antidysrhythymic)
R: can cause depression because can cross BBB
P: alpha-1 specific blocker [alpha-1 receptor blockade causes relax. of smooth muscle & decr. vasc. resist.) **Substantial 1st pass effects, still useful orally w/adjusted dose.
Cannot use w/Sympathomimetics OTC (cold meds.=decongestants). Activate sensitive alpha-receptors. Trycyclic antidepressants prevent uptake of G. into neurons.
affects postgang. neurons of PSNS. [G: displace. of norepi. from granules & inhibit. of release of norepi.] & [R: depletion of catecholamines from granules]
treat HTN
Cardiac Arrythymias
Essential HTN
Andrenergic Antagonists: alpha-blockers
2nd line treatment of HTN
GUANETHIDINE, RESERPINE
competitive inhibition of beta-receptors, decr. C.O., & decr. vasc. resist. **1st pass effect
P: first dose response (severe hypotension in response to 1st dose), depression, fatigue, fluid retention
G: orthostatic Hypotension
treat essential HTN
M: sedation, lassitude, hepatotoxicity, hemolytic anemia
Centrally Acting Sympatholytics
alpha-2 agonists @ central receptors, decr. vasc. resist., decr. C.O., decr. sympathetic output
C: sedation, depression, reound HTN
