Lec 19 Vasodilators and Ca Channel Blockers Flashcards
What is angina?
chest pain caused by cardiac ischemia
What is purpose of pharm management of angina?
reducing myocardial O requirement
What type of drugs can you use to treat angina?
vasodilators: nitrates and Ca blockers
cardiac depressants: Beta blockers
What is goal of anti-anginal therapy?
reduce myocardial O2 consumption by reducing one or more of the following: end diastolic volume, blood pressure, heart rate, contractility
What is mech of action of nitrates?
release NO –> stimulate cGMP –> smooth muscle relaxation –> dilate veins > arteries > arterioles
How does smooth muscle relaxation of nitrates decrease myocardial O2 demand?
dilate veins –> decrease preload
dilate arteries –> decrease afterload
Do nitrates mostly affect afterload or preload?
preload [b/c dilate veins more than arteries]
What is use for nitroprusside?
short acting nitrate
increases cGMP by direct release of NO –> vasodilation
used in hypertensive emergency
What other drug should you avoid giving along side nitrate?
phosphodiesterase 5 inhibitor like sildenafil –> cause profound hypotension
What are side effects of nitrates?
- reflex tachycardia
- orthostatic hypotension
- headache from vasodilation of meningeal artery
- tolerance
Which drug should you worry about cyanide poisoning?
long term use nitroprusside = metabolized to cyanide
What are the 2 dihydropyridines?
Ca blockers:
nifedipine
amlodipine
What are the 2 non-dihydropyridines?
Ca blockers:
dilitiazem
verapamil
What is order of activity in vascular smooth muscle: diltiazem verapamil amlodipine nifedipine
amlopidine = nifedipine > diltiazem > verapamil
What is order of activity in cardiac smooth muscle: diltiazem verapamil amlodipine nifedipine
verapamil > diltiazem > amlodipine = nifedipine
