Vasodilators Flashcards
Nerve stimulation, endothelilal signaling, and SMC stretch control
SMC tone
PRotects distal capillary beds from high pressure
SMC stretch
Used in the treatment of HTN and angina
-Bind L-type Ca2+ channels
Calcium Channel Blockers (CCBs)
The CCBs that control vascular tone are primarily
Arterial Vasodilators
Have negative chronotropic and inotropic effects on the heart and promote relaxation
CCBs
What are the three classes of CCBs?
Dihydropyridines, phenylalkylamines, and benzothiazepines
Have a preference for inactivated Ca2+ channels
Dihydropyridines
VSMC have a higher RMP (-70) when compared to cardiomyocytes (-90). This more Ca2+ chanels are inactivated and will bind DHP at
Lower doses
Have a preference for open Ca2+ channels
Non-dihydropyridines
Dihydropyridines act on
VSMC
Are equipotent for cardiac tissue and vasculature
Non-dihydropyridines
Verapamil and Diltiazem have negative effects on
HR and contractility
Nifedipine and amlodipine act as
Arterial vasodilators
Have a rapid onsent of action and short half-life, which can cause a precipitous drop in BP
CCBs
Initial monotherapy for patients w/ hypertension
CCBs (dihydropyridines)
Which CCB is used for hypertensive emergency?
Clevidipine
Which CCB do we use to trat ventricular tachyarrhythmias
Verapamil
Can cause headaches, dizziness, light-headedness, and flushing
Vasodilation
CCBs are contraindicated in
AV-block or WPW + Afib
One of the oldest cardiac therapies
-used for stable and unstable angina
Nitric Oxide Donors (NODs)
Acts on veins
-Has less arterial effects
NOD
Results in increased venous capitance and decreased LVEDV and LVEDP
NOD
Which NOD is the exception in that it acts on arteries more than veins?
Sodium nitroprusside
Mild arterial vasodilation also occurs w/ NODs, this can minimizes
Coronary Steal
Do not cause coronary steal syndrome
Nitrates
Decreae preload and myocardial O2 demand in low doses
Nitrates
In HIGH doses, nitrates decrease
Afterload and myocardial O2 demand
Also causes smooth muscle dilation of esophagus, intestines, and genitourinary tract and inhibits platelet aggregation
NOD
Can be used to treat esophageal spasm
NTG
What are the three classes of nitric oxide donors?
Ihaled NO, organic nitrates, and inorganic nitrates
Enzymatically reduced to S-nitrosothiols (RSNO)
-Confers tissue specificity
Organic Nitrates
Redued to NO by tissue enzymes
RSNO
Has a rapid onset of action but less bioavailibility
Sublingual NTG
Sublingual NTG provides raid relief of
Anginal symptoms
has a 100% bioavailability orally and has a long half-life
Isosorbide mononitrate
The number one adverse effect of organic nitrates is
Headache
Directly reduced by oxyhemoglobinto NOplus cyanide
Sodium Nitroprusside (SNP)
Causes both arteriolar AND venous dilation
SNP
Very rapid onset and short duration of action Requires continuous infusion and BP monitoring
SNP
SNP is effective for
Hypertensive emergency
Can cause cyandide toxicity and thiocyanate toxicity w/ renal insufficiency
SNP
We can treat cyanide toxicity w/
Sodium thiosulfate
Causes disorientation and confusion w/ muscle spasms
Thiocyantate toxicity w/ renal insufficiency
Hypotension, increased ICP, and diastolic HF are contraindication to
NODs
What is a major contraindication to NODs?
Phosphodiesterase 5 inhibitors
Direct-acting arterial vasodilator
-NOT a first line drug for hypertension
Hydralazine
Used with isosorbidedinitratefor the treatment of heart failure
Hydralazine
Phosphodiesterase type 5 is a potentiator of
NO signaling
Phosphodiesterase 5 inhibitors are used for
Erectile Dysfunction
When phosphodiesterase 5 inhibitors are used w/ NO donors, we can see
SEVERE refractory hypotension
Peripheral dopamine-1 receptor agonist
Fenoldopam
Arteriolar vasodilator used for hypertensive emergencies
Fenoldopam
Use w/ caution in glaucoma b/c it can cause increased ICP
Fenoldopam
