Chapter 21: Vascular Tone Flashcards
How do nitrates work?
NO activates guanylyl cyclase and increases DEphosphorylation of myosin light chain in vascular smooth muscle. This case vasodilation.
What drug selectively dilates pulmonary vasculature?
Inhaled nitric oxide gas
(makes sense - INHALE/GAS/LUNGS!
Which drugs dilate veins moreso than arteries?
Isosorbide dinitrate
Isosorbide 5 mononitrate
NTG
Which drug targets arteries and veins equally by a non-enzymatic process? It is used for hypertensive emergencies.
Sodium nitroprusside.
Which drug comes in a transdermal patch that you should remove at night to prevent tolerance and “Monday Morning headaches”?
NTG
Why isosorbide 5 mononitrate preferred over dinitrate?
It has a longer half life, is absorbed better from the GI tract, less reboudn angina….
Which nitrate is used for newborns with hypertension?
Inhaled nitric oxide gas
How does NTG prevent coronary steal?
Preferentially dilates larger epicardial arteries than the smaller coronary arteries
With what nitrate do you have a risk for cyanide toxicity?
Sodium nitroprusside (sounds like an evil little bitch…like the king of PRUSSia)
What are nitrates typically used for? Short acting vs. long acting?
Acute angina attacks
Chronic heart disease
When does cyanate toxicity become life threatening? concentration?
200mg/L
SildenaFIL
VardenaFIL
TadalaFIL
MOA: Phosphodiesterase inhibitors (PDE5) leads to cGMP accumulation = smooth muscle relaxation
TX: ED
Phosphodiesterase inhibitors are contraindicated when?
patients also taking organic nitrates NO NO NO DON’T DO ITTT
Also pts with a history of vision loss
Sildenafil can be used to treat ED and what else?
pulmonary hypertension
How do calcium channel blockers work?
They block voltage gated Ca channels so you prevent actin myosin cross bridge formation.
Nifendipine
Ca channel blocker
Serious reflex tachycardia
Amlodipine
Ca channel blocker
Higher bioavailability
Felodipine
Ca channel blocker
Clevidipine
Ca channel blocker
IV infusion for hypertension emergencies
Which Ca channel blockers favor arterial vasodilation?
dyhydropyridines
Diltiazem & verapamil
Ca channel blockers with less vascular to cardiac selectivity….
Use for Prinzmetal angina, hypertension, tachycardia
Verapamil w/alcohol makes alcohol more potent
What Ca channel blocker has the most cardiac effect?
Verapamil (suppresses cardiac conductivity most)
MOA potassium channel openers
open ATP modulated K channels and hyperpolarize the membrane –> inhibit influx of Ca –> decrease arterial BP
Minoxidil
Pinacidil
Nicordandil
“Dil Pickle Potassium”
MOA: K channel opener
TX: severe hypertension or hair loss (ROGAINE!!!)
Use with beta blocker and diuretic to prevent reflect tachycardia
