Drug that selectively targets and reduces heart rate by inhibiting the SA pacemaker current.
First line therapy for acute angina symptoms
What class of drugs can be used as prophylaxis for episodes of angina?
Vasodilators (ie. nitrates) are metabolized in their target tissues to their active compound ____ also known as ___
NO= endothelium derived relaxing factor
In smooth muscle, NO stimulates ______ --> cGMP --> Protein Kingase G -->___________--> Relaxation
Myosin light chains phosphatase
What class of drugs relaxes vascular smooth muscle only and what is the rank in which it affects these?
Veins >> arteries >> Arterioles
Nitrates have a major action in reducing _____ on the heart.
Nitrates have ____ and ____ properties.
When are these seen?
Seen w/ IV or transdermal administration of nitroglycerin in treating unstable angina.
Nitrate stimulation of guanylate cyclase prevents _____ binding to ______ receptors
fibrogen, platelet IIb/IIIa receptors
Major effect of organic nitrates?
Reduction in myocardial oxygen demand
How do nitrates decrease the preload and afterolad? This decreases the amnt the heart has to work and thus decreases the oxygen needed to sustain the myocardium.
Venous dilatation results in pooling of blood in veins --> decreases volume of blood returning to the heart (reducing preload)
Decrease in blood pressure decreases cardiac afterload.
Volatile liquid given by inhalation- rapid acting short duration (few minutes); no longer used for angina because it causes methemoglobin at high blood concentrations.
Use for potential antidotal action in cyanide poisoning.
Which has the greatest first pass effect via the liver: Nitroglycerin, glyceryl dinitrate or glyceryl mononitrate?
NG > glyceryl dinitrate >>>> glyceryl mononitrate
Isos are about equal to each other.
Workers who are constantly exposed to NG, lose tolerance over weekend and come back on Monday. They get headache, dizziness, tachycardia, etc.
What are the advantages of sublingual or buccal administration of NG compared to oral?
It avoids hepatic first pass inactivation
Therapy of choice for acute anginal episodes and prophylactically for activities konwn to elicit angina.
Tolerance is generally not a problem with what form of NG?
3 contraindications for Nitrates
Patients on PDE5 inhibitors (sildenafil, viagra, etc) --> dangerous hypotension