Direct Vasodilators Flashcards
Minoxidil
oral
Relaxes ARTERIOLE smooth muscle by opening K+-ATPase channels
(dilates arteries, NOT veins)
Causes reflex tachycardia and strong renin release!! (so take w/ BB and diuretics long-term)
Causes Hirsutism (increases hair…)
Rogaine!…male-pattern baldness
Nitroprusside
Pro-drug that’s broken down into NO
–>increase in cGMP–> muscle relaxation
active in arterioles AND mainly veins!!!
Awesome for HF treatment!
Decreases CO in normal pts
Increases CO in pts w/ Left ventricular HF b/c decreases afterload (along w/ preload)
Very short half-life, given w/ pump
Hydralazine
selective arteriole vasodilator (NOT in veins)
–Sympathetic nervous system activated–> catecholamine/renin secretion–> increased HR and contractility, venoconstriction, Na/H2O retention
So decrease in BP causes fluid retention
- **Used w/ BB and diuretics long-term
- -BBs decrease contractility, HR, and renin release
- -diuretics fight Na/fluid retention
pre-eclampsia! OB-GYNs like
Diazoxide
IV for HTN emergencies
Prevents vascular smooth muscle contraction by opening K+ channels…
–stabilizes resting membrane potential (-60 may go down to -80mV)
reflexive tachycardia and renin secretion
–(so increases CO and fluid retention)
Best if given w/ BB
Side effects…hyperglycemia (b/c inhibits insulin release)
–used in pts w/ insulinomas
Fenoldopam
D1 agonist
(found in arterioles in kidney)
especially good if renal HTN
Very short half-life
given via pump
Reflex tachycardia
increased IO pressure so avoid in pts w/ glaucoma
General
usually used in hospital setting for HTN emergencies
–pre-eclampsia
Hydralazine side effects
palpitations/pronounced tachycardia (may trigger angina)
Autoimmune rxns
–hemolytic anemia, GN, SLE-like syndrome
Nitroprusside Side Effects
excessive hypotension
pronounced tachycardia (palpitations)
metabolized to cyanide
–cyanate or thiocyanate toxicity (give smallest dose for shortest period)
