Anti-Anginals and ED Drugs Flashcards
Classes of drugs used for angina
Organic nitrates
Calcium channel blockers
Beta blockers
Main mechanism/goal of anti-anginal drugs
Reduce myocardial oxygen demand
Factors that determine myocardial oxygen demand
Heart rate
Contractility
Ventricular wall stress (preload and afterload)
Ways to reduce myocardial oxygen demand
Reduce preload or afterload
Reduce heart rate and contractility
Shift cardiac energy metabolism from oxidation of fatty acids to use of glucose (anaerobic metabolism)
Factors that determine myocardial oxygen supply
Arteriolar dilation of coronary blood flow
Duration of diastole
Ways to increase myocardial oxygen supply
Reduce heart rate
Dilate coronary arteries
Prototype organic nitrate drug
Nitroglycerin
Nitroglycerin MOA
Prodrug that releases NO when metabolized by ALDH-2
Effect of nitroglycerin on heart
Dilates veins to decrease venous return and decrease preload to reduce oxygen demand
Modest dilation of large epicardial arteries to increase blood flow to regions of ischemia
When is nitroglycerin used?
Prophylaxis and termination of acute a final attacks
Improves exercise tolerance
No survival benefit or prevention of MI
Patient population that may not be able to metabolize nitroglycerin well due to ALDH-2 polymorphism
Patients of Asian origin
Fast acting route of administration of nitroglycerin
Sublingual (1-2 minutes, lasts less than 1 hr)
Tolerance to organic nitrates is more common with what route of administration
Oral and transdermal
How to minimize nitroglycerin tolerance
Eccentric dosing (nitrate-free intervals of 10-12 hours)
Adverse effects of nitroglycerin
Headaches
Facial flushing
Orthostatic hypotension
Reflex tachycardia
Nitroglycerin drug interactions
Vasodilators
Alcoho;
Two subclasses of calcium channel blockers
Dihydropyridines
Heart-rate lowering
Dihydropyridine drug
Nifedipine
Heart-rate lowering calcium channel blocker drug
Verapamil
MOA of calcium channel blockers
Block intake of Ca2+ through voltage gated L-type calcium channels by binding to sites on the alpha 1 subunit
Vasodilators of peripheral and coronary arteries to decrease afterload and oxygen demand
When are calcium channel blockers used for angina?
Prophylaxis
Nifedipine acts mostly on what kind of tissue?
Vascular smooth muscle
Verapamil acts mostly on which tissues?
SA and AV nodes
Nifedipine has many drug interactions because it is metabolized by CYP___
CYP3A4
Verapamil contraindications
Sick sinus syndrome
AV nodal block
clinical uses of calcium channel blockers
Angina
Hypertension
Arrhythmias
Adverse effects of calcium channel blockers
Bradycardia in HRLs
Reflex tachycardia, headache, and flushing in DHPs
GERD
Beta-1 selective blocker drug
Metoprolol
Metoprolol MOA
Decrease HR, contractile force, and BP to decrease myocardial oxygen demand
And increase oxygen supply
Goal resting HR with B-blocker
55bpm
Goal exercise BP with B-blocker
110-120 bpm
Angina drug that reduces mortality
B-blockers
What angina drug may worsen variant angina?
B-blockers
Adverse effects of B-blockers
MI if sudden withdrawal
Exercise intolerance
Bronchoconstriction
Sexual dysfunction
Drug combination of anti-anginal drugs to avoid prescribing together
Beta blockers with HRL calcium channel blockers
Drug class used for erectile dysfunction
Phosphodiesterase type 5 (PDE5) inhibitors
PDE5 inhibitor drug
Sildenafil
MOA of sildenafil
Selective inhibitor of PDE5 in corpora cavernosa that prolongs activity of endogenous cGMP to relax smooth muscle and increase blood flow
When should sildenafil be taken?
1 hour before sexual activity
Clinical uses of sildenafil
Erectile dysfunction
Pulmonary hypertension
Adverse effects of sildenafil
Headache and flushing
Abnormal vision
Dyspepsia
Sudden hearing loss
Priapism
Drug interactions with sildenafil
Organic nitrates
Alpha blockers
