Vasodilators Flashcards
What happens to O2 demand in stable angina?
Increases
B/c:
- ^ HR
- ^ Contractility
- ^ Wall tension
What happens to O2 supply during thrombus formation in unstable angina?
Decreases
How do you manage angina?
- Risk factor modification (HTN, diabetes, smoking, dyslipidemia)
- Aspirin (low dose)
- Statins
What is the overall goal of pharmacotherapy in the mgmt of angina?
- Restore balance between O2 demand and supply
- Increase supply
- Decrease demand
How do you improve coronary blood flow?
Primary: surgical w/ CABG-PTCA
Secondary: vasodilators
How do you reduce myocardial O2 demand?
- Vasodilators (e.g. nitrates)
- Negative inotropes and chronotropic agents (e.g. CCBs, BBs)
Describe the acute therapy for a ruptured atheromatous plaque w/ occlusive thrombus (unstable angina => MI)
- Medical emergency (ACS)
- Clot => anti-platelet, anticoagulant, surgery, fibrinolytics
- Arrhythmias => Beta-blockers
- Pain => NTG, morphine
Describe the post-MI therapy
- ACEIs
- Statins
- BBs
- Aspirin
- Clopidrogel (if post-stent)
How do you chronically treat coronary vasospasm due to variant angina?
- Happens b/c O2 supply decreases
- Goal: reverse or prevent vasospasm and increase supply
Use:
- vasodilators (nitrates)
- CCBs
What is the MOA of nitrates?
- Nitrates => NO
- NO activates guanylate cyclase => ^ GTP to cGMP
- ^ cGMP => SM relaxation
- Results in reduction of LVEDP and systemic vascular resistance
What is the primary effect of nitrates?
Decreased wall tension => decreased myocardial O2 demand
What is the secondary effect of nitrates?
Improves perfusion of ischemic myocardium
How do nitrates affect HR, contractility, systolic pressure, and LV volume?
HR: increase
Contractility: nothing
SP: decrease
LV vol: greatly decrease
What is the onset/duration of IV nitroglycerin?
O: 1-2 minutes
D: 3-5 minutes
What is the onset/duration of sublingual nitroglycerin?
O: 1-3 min
D: 30-60 min
