module 7 vasodilators and digoxin Flashcards
hydralazine mechanism of action and use
vasodilator stimulates NO production in endothelial cells -> arterial dilation Uses: - HTN - HF
hydralazine adverse effects
fluid retention
reflex tachycardia
drug fever
peripheral neuropathy
rare: reversible systemic lupus like syndrome
tachyphylaxis (less effect over time) due to having to replenish NO stores
hydralazine contraindications
CAD
rheumatic mitral valve disease
minoxidil mechanism of action and use
K channel opener
causes hyperpolarization of smooth muscle membrane -> dec. excitation and contraction -> arterial vasodilation
Use:
- refractory HTN
active metabolite can cause hypoTN for 24hrs
minoxidil contraindications
acute MI
pheochromocytoma
aortic dissection
minoxidil adverse effects
fluid retention
rebound tachycardia
hypertrichosis: hair growth (can be used for alopecia)
fenoldopam mechanism of action and use
vasodilator D1 receptor agonist - dec peripheral vascular resistance and inc. renal blood flow - inc. diuresis and natriuresis Use: - HTN emergency - IV: short-term use up to 48 hrs
fenoldopam adverse reactions
hypoTN
tachycardia
headache
flushing
Sodium nitroprusside mechanism of action
vasodilator
produces NO -> smooth muscle relaxation
vasodilates arteries and veins
sodium nitroprusside use
HTN emergencies
- rapid onset of action
- very short duration of action
- IV infusion only
sodium nitroprusside adverse effects
risk of cyanide toxicity
-> blurred vision, confusion, tinnitus, seizures, acid-base imbalance, and arrhythmias
metabolized into NO and cyanide -> thiocyanate -> renal excretion
digoxin Mechanism of action
considered for all HF pt who have not responded symptomatically to other Rx tx.
- AV nodal and inotropic effects
- inc PSNS outflow
inhibits Na-K ATPase
nitrates
nitroglycerin
isosorbide mononitate
isosorbide dinitrate
nitrate mechanism of action
inc. concentration of NO in smooth muscle cells
- > activation of cGMP
- > smooth muscle relaxation
dec. venous blood return to the heart
dec. preload
nitroglycerin site of admin
sublingual tablets spray topical patch or paste IV - high first-pass effect 90% degraded in liver