Vasodilators
Terms
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- Short acting nitrates
-
amyl nitrate (inhaled)
nitroglycerin
isosorbide dinitrate - inhaled short acting nitrate
- amyl nitrate
- reason for using inhaled or sublingual nitrates
- avoid first past hepatic metabolism
- mechanism of action for nitrates
- NO activates guanylyl cyclas which lowers Ca and causes relaxation
- NO preferentially dilates which vessels
- veins>>arteries>>arterioles
- when can nitrates dilate large arteries aand decreases BP
- when given at high doses
- Reflex to NO
-
catecholamine release to increase HR and contractility
increse Renin/Ang system - How long must a person wait to take Viagra after taking nitrates
- 6 hours
- Nitrates effects beyond vasodilation
-
Decrease platelet aggregation (though no effect on acute MI)
Converst Hb to metHb which sequesters CN - Uses for nitrates
- Angina (stable, variant and unstable)
- Toxicities of nitrates
-
Reflex increase in HR, contractility
Postural Hypotension
Throbbing headache
Tolerance (reversible after 8/12 hours off) - Mechanism of nitrate tolerace
- exhaust tissue thiols necessary to convert NO2 to NO
- Calcium channel blockers
-
verapamil
Diltiazem
Nimodipine
Nifedipin
Nifedipine sustained release
Isradipine
Amlodipine - Ca blocker without high first pass metabolism
- amlodipine
- amlodipine differs from other Ca blockers because?
- it does not have a high first pass metabolsim
- Ca blockers that can be given IV
-
verapimil
diltiazem - phenylalkylamines
- verapamil
- benzothiazepines
- Diltiazem
- Dihydropyridines
-
Nimodipine
Nifedipine
Isradipine
Amlodipine - preferential dilate of Ca channel blockers
- arterioles>arteries>>veins
- selective for cerebral blood vessels
- Nimodipine
- special use for Nimodipine
- cerebral vasospasm
- these drugs do not show a reflex response
- Ca channel blockers
- Ca channel blockers effect on kidneys
-
Increase RBF, GFR
Decrease sodium reabsorption
May worse proteinuria - May worse proteinuria
-
Ca channel blockers
Verapamil
Diltiazem
Nimodipine
Nifedipine
Isradipine
Amlodipine - Ca channel blockers effect on heart
-
decrease contractility
decrease rate
decrease AV node conduction - Uses for Ca channel blockers
-
Angina
HTX
Cardiac arrythmias
Vasospasm
Multidrug resistance - These two Ca channel blockers block cardia Ca channels
-
Verapamil
Diltiazem
Bind in open-state - May block cardiac Na channels
- Verapamil
- Uses for spraventricular tachyarrhytmias
-
Diltiazepam
Verapamil - Used to increase diastolic filling time
-
Verapamil
Diltiazem - uses for cerebral vasospams
- Nimodipine
- used to block chemo drug transmport out of cells
- Verapamil
- multi drug transporter blocked by verapamil
- P170
- Toxicities of nonDHPs
-
cardiac arrest
bradycardia
AV block
heart failure - mild Ca channel toxicities
- headaches, nausea, flusshing, constipation, dizziness, peripheral edema
- hydralazine is used in combination with?
- beta blockers for sever hypertension
- when used with beta block, cause relieve sever hyptertension
- hydralazine
- Your pateint begins having joint paint, muscle pain and a skin rash after receiving blood pressure medicine. Which one did she receive?
- hydralazine
- toxicities of hydralazine
- arthralgia, myalgia, lupus like skin rash (10%)
- site of action for minoxidil
- dilates arterioles, not veins
- mechanism of action for minoxidil
- open K channels and hyperpolarizes muscle
- minoxidil is a prodrug for what active component
- minoxidil sulfate
- side effects of minoxidil
-
hypotension
reflex response
hirsuitism - site of action for Sodium nitroprusside
- arteries and veins
- mechanism of action for sodium nitroprusside
- generates NO to dilate veins with little reflex tachy
- side effects of sodium nitroprusside
-
hypotension
generation of CN - uses for sodium nitroprusside
- HTX emergencies and severe cardia failure