Drugs that affect the Vasculature Flashcards
What classes of drugs act on the vasculature? (there are more but this lecture focuses on 2 main types)
Vasodilators
Anti-adrenergic
What are the 4 direct acting vasodilators?
Hydralazine
Minoxidil
Sodium nitroprusside
Fenoldopam
Hydralazine
Direct acting vasodilator- arteriole vasodilator
Htn, heart failure (+nitrate)
Decreases resistance to LV doesnt need to pump as hard –> increases CO
Low bioavailability, short half life
SE: HA, palpitations, flushing, nausea, anorexia, lupus like syndrome
Minoxidil
Direct vasodilator: arteriolar (increased K channel permeability)
Severe or refractor htn (rarely used!)
SE: reflex tachycardia, fluid retention, hypertrichosis (excessive hair growth–ROGAINE), pericardial effusion
Sodium nitroprusside
“balanced” vasodilator- acts on arteries and veins; potent/rapid
metabolized to NO and to cyanide
Decrease arterial/systemic resistance, increase venous capacitance – works best on pt with normal or reduced LV function
Treat hypertensive emergency (with beta blocker) & severe CHF – IV infusion, 30 seconds to on, minutes off
SE: thiocyanate toxicity –> blurred vision, tinnitus, disorientation, nasuea
Fenoldopam
Direct acting vasodilator– arteriolar
dopamine 1 agonist –> vasodilation
Thought to enhance renal perfusion
IV, rapid onset, rapid offset, metabolized in liver, renally excreted
SE: HA, dizzy, tachycardia, increased intraocular pressure (avoid in pt with glaucoma)
Nitrates
What conditions? Mechanism? Contraindications? How administered?
Vascular smooth muscle relaxation –> venodilation –> CO falls secondary to this
Use for angina, acute coronary syndromes, HF
Don’t use in preload sensitive patients i.e. RV MI
Fast acting formulas for acute i.e. sublingual
Chronic i.e. oral, transdermal
IV nitroglycerin for unstable angina, pulm edema, HF
Drug tolerance develops with continued use- drug holiday
SE: hypotension, reflex tachycardia, HA, flushing
What is the main 5-phosphodiesterase-5 inhibitor?
Sildenafil
Sildenafil
PhDiEs-5 inhibitor –> decreases pulm vasc resistance in pt with pulm arterial htn
Don’t use with nitrates or viagra!! Severe systemic hypotension
Calcium Channel blockers: how they work and 2 main classes
Decreases intracellular Ca concentrations –> vasodilation in vasc smooth muscles and/or inotropic effect in cardiac cells
- *Non-dihydropyridines**: mainly negative inotrope
- Verapamil
- Diltiazem
Dihydropyridines: mostly vasodilators
“-ipine”
When do you use Ca Channel blockers?
2nd line for angina
Coronary artery spasm
Htn
Verapamil and Dilitazem: Supraventricular Arrhythmias
What are the SE of Ca Channel blockers?
Verapamil: hypotension, bradycardia, AV block, constipation
Diltiazem: hypotension, peripheral edema, bradycardia
Dihydropyridines: hypotension, HA, flushing, peripheral edema (esp amlodipine)
What are the 4 main anti-adrenergic classes?
CNS alpha 2 agonists
Beta blockers
Peripheral alpha antagonists
Reseripine: sym nerve ending antagonist
Alpha and beta receptors location/response
What are the CNS alpha 2-antagonists? What is their effect?
Diminished sympathetic outflow from the medulla –> decreased peripheral vasc resistance, drop in BP and HR
Clonidine, alpha-methyldopa, guanabenz, guanfacine
SE: refractory htn
