cardiovascular drugs Flashcards
What are arrhythmias caused by
- Aberrations in impulse general (abnormal automaticity)
2. Defects in impulse conduction
cardiac output =
CO = HR X SV
Stroke volume =
SV = EDV - ESV
Preload
Filling pressure at end of diastole
Afterload
pressure against which heart must work to eject blood during systole
Name 3 major determinants of myocardial O2 demand
- Heart rate
- Contractility
- Wall stress
Arterial Blood Pressure =
ABP = HR X SV X TPR
ACE inhibitor Captopril - Half life
Short half life 2.5 hrs
ACE inhibitor lisinopril, enalopril - Half life
Long half life
ACE inhibitor additional mechanism
inhibits degradation of bradykinin - has vasodilating activity
Calcium channel blocker Dihydropyridines - e.g.
Nifedipine (binds to N site) - in a completely different region of the channel
Have a greater affinity for vascular Ca+2 channels
Calcium channel blocker benzothiazepines - e.g.
Diltiazem (binds to D site) (D and V sites of the channel overlap)
Calcium channel blocker Diphenylalkylamines - e.g.
Verapamil (binds to V site)
Effects of calcium channel blockers
- dilate coronary artiers
- Increase myocardial O2 supply
- decrease myocardial contractility
- SA and AV node action
- DO NOT EFFECT SKELETAL MUSCLE
What is the role of cGMP?
cGMP when activated, activates MLC-phosphatatse
What are the agents used for treating Angina
Nitrates
B blockers
Ca channel blockers
At therapeutic doses, what type of dilation predominates with the use of organic nitrates
Venous capacitance is increased predominantly
Which method of use of Nitroglycerin has the longest onset of action and longest duration
Trans-dermal patch
Isosorbine mono and dinitrate are best with oral SR and XR tablets
