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42 Cards in this Set
- Front
- Back
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What is HTN defined as?
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sustained diastolic BP >90
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What is the major long-term regulator of BP?
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renin-angiotensin-aldosterone
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What is the main benifit of treating HTN?
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prolongs life
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What are 2 main factors to compliance?
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complexity of regimen
side effects |
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What are the 2 main features of a direct vasodilator?
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dilate in the absence of SNS
non-specific antagonizers of constrictors |
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Where is the main site of action of vasodilators?
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peripheral arterioles
little effect on veins |
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What are the compensatory mechanims to vasodilators?
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reflex tachycardia
refelex release of renin Na/H20 retention |
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What is the mechanism of reflex tachycardia?
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inc CO
inhibited by B Blockers may cause angina due to increased myocardial 02 demand |
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What are the direct vasodilators?
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Hydralazine
Minoxidil Nifedipine, Diltiazem, verapamil diazoxide Sodium Nitroprusside Fenoldopam |
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What is the pneumonic for vasodilators?
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How Many Nifty Doctoring Vets Does Somebody Need Freed?
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What is hydralazine used to treat?
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chronic HTN
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What do you use in combination with vasodilators?
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BB - reduce reflex tachy
diuretic - reduce Na/H20 |
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How is hydralazine inactivated?
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acetylation
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What are the major SE of hydralazine?
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headache, palpitations, tachycardia, dizziness, edema & lupus-like syndrome
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What is Minoxidil used to treat?
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refractory HTN
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What is the mechanism of action of minoxidil?
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opens ATP-sensitive potassium channels in vascular smooth muscle
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What are the side effects of minoxidil?
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tachycardia, edema, hair growth
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What else is minoxidil used for?
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topically to cause hair growth
rogaine! |
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How does Nifedipine, diltiazem & verapamil work?
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blockade of voltage-dependent Ca channels
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Where do the CCB work?
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mainly on arterioles
GI & bronchial SM |
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What do CCB cause?
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vasodilation & corresponding drop in BP that does NOT go below normal
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How do you find CCB in plasma?
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bound to plasma protiens
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What are the SE of CCB?
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flushing, headaches
Verapamil - dec AV conduction, constipation Nifedipine - edema |
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What is diazoxide used to treat?
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HTN emergencies - bp rarely falls below normal
IV! |
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What is the mechanism of action of diazoxide?
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opens ATP-sensitive potassium channels
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How do you give diazoxide?
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IV bolus
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Why does diazoxide have to be given in an IV bolus?
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highly bound to plasma protiens
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What does the rate that diazoxide is given determine?
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extent & duration of BP fall
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What are the SE of diazoxide?
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reflex tachycardia, hyperglycemia, edema
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How does the dramatic is the drop in BP due to diazoxide?
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rarely falls below normal
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What is sodium nitroprusside used to treat?
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HTN emergencies
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How does sodium nitroprusside work?
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metabolized into NO
acts by increasing cGMP in vascular SM |
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What is s SE of sodium nitroprusside metabolism?
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metabolized to cyanide & thiocyanide which accumulate with prolonged therapy & is excreted slowly
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Where does sodium nitroprusside act?
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dilates both arteries & veins
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What is the consequence of dilating both arteries & veins?
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no change in CO
venous pooling decreases VR |
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What is the mechanism of action of Fenoldopam?
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parenteral dopamine A1 agonist
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What does fenoldopam do at high concentrations?
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blocks alpha adrenergic receptors 1>2
activates adenylyl cyclase & increases cAMP |
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What is the effect of fenoldopam?
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lowers systolic & diastolic BP
dilates renal & mesenteric vascular beds |
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What is the effect of dilation of renal vasculature?
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increased RBF
no change in GFR |
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What is fenoldopam used to treat?
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HTN emergencies & post-op HTN
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What are the side effects of fenoldopam?
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increased intra-ocular pressure, flushing, headaches, sinus tachycardia, may precipitate angina
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What are the contraindications of fenoldopam?
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glaucoma, angina, heart failure
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