Anti Anginals Flashcards
three types of angina
chronic stable
unstable
prinzmetal (variant)
what is chronic stable angina caused by and what does it lead to
chronic narrowing of coronary arteries due to atherosclerosis leading to increased oxygen demand –> pain with a predictable threshold of physical activity
what is unstable angina caused by and what does it lead to
transient formation and dissolution of a blood clot within a coronary artery due to an atherosclerotic plaque rupture –> reduction in oxygen supply
what is prinzmetal variant angina caused by
coronary spasm which temporarily reduces coronary blood flow
short term and long term goals of antianginal therapy
short term: reduce or prevent anginal symptoms that limit exercise capability and quality of life
long term: prevent MI, arrhythmias, heart failure, and extend pt’s life
what does angina result from
reduction in oxygen supply/demand ratio hence anti anginals improve this ratio
drugs used to treat angina
- vasodilators (increase oxygen supply and decrease oxygen demand): calcium channel blockers and nitrates
- cardioinhibitory drugs (decrease oxygen demand): beta blockers and calcium channel blockers
- ranolazine: sodium channel blocker
- anti thrombotic drugs: anti coagulants and anti platelet drugs
what are the calcium channel blockers
VAND verapamil amlodipine nifedipine diltiazem
what are calcium channel blockers used to treat
- hypertension, angina, and arrythmias
- treats all three types of angina: chronic stable, unstable angina, prinzmetal angina
what are used in combination with dihydropyridines and why
beta blockers are used with amlodipine and nifedipine because of reflex tachycardia
also used if beta blockers are contraindicated
what are the anti-anginal effects of CCBs
increased vasodilation –> increased oxygen supply
cardiodepressant –> reduce oxygen demand
importance of CCB dilating the coronary arteries other than increasing oxygen supply
reverse coronary vasospasm that occurs in prinzmetal variant angina
adverse effects of calcium channel blockers
- dihydropyridines: reflex tachycardia, dizziness, flushing, headache, hypotension, constipation, and peripheral edema
- non-dihydropyridines: cardiac conduction abnormalities (bradycardia, AV block and heart failure), anorexia, nausea, hypotension, peripheral edema
contraindications for CCBs
bradycardia, conduction defects, heart failure
nitrates used to treat angina
isosorbide dinitrate
isosorbide mononitrate
nitroglycerin
sodium nitroprusside
clinical application of nitrates (name them again)
isosorbide dinitrate, isosorbide mononitrate, nitroglycerin, sodium nitroprusside
for stable, unstable, and variant
nitrogylcerin: first line for acute anginal symptx
nitroprusside: emergency and ICU settings
isosorbide mononitrate and dinitrate: prophylaxis
mechanism of nitrates
they work via NO
- relax vascular smooth muscle (vasodilation)
- inhibit platelet aggregation (anti-thrombotic)
- inhibiting leukocyte endothelial interactions (anti-inflammatory)
why does tolerance develop rapidly with nitrates and how is it overcome?
vessels become desensitized to the vasodilatory effects of nitrates
overcome by infrequent dosing with smallest amount possible
of all the nitrates which has longest half life and importance
isosorbide dinitrate and mononitrate
impo because it can be used for long term therapy
adverse effects of nitrates
hypotension reflex tachycardia headache (cerebral vasodilation) facial flushing nitroprusside - cyanide toxicity
contraindication of nitrates and why
sildenafil (cGMP dependent phosphodiesterase) used to tx erectile dysfunction –> inhibits breakdown of cGMP –> increase in plasma cGMP –> hypotension and impaired coronary perfusion
beta blockers used for anginas
MAP
metoprolol
atenolol
propanolol
clinical use of beta blockers in angina
pts with stable angina who have had ACS (acute coronary syndrome - STEMI, nonSTEMI) or who have left ventricular dysfunction
what are the anti anginal effects attributed to beta blockers
they reduce workload of the heart hence decreasing oxygen demand
adverse effects of beta blockers
- hypoglycemia
- bronchoconstriction
- CNS effects
- disturbed lipid metabolism
- CV effects: bradycardia, heart failure, hypotension, heart failure, reduced exercise capacity
- drug withdrawal: abrupt cessation can cause unstable angina, MI, or death due to upregulation of beta receptors during blockade
contraindications for beta blockers
- restrictive airway disease (COPD, asthma)
- sinus bradycardia and partial AV block
- heart failure
- variant angina: beta blockers reduce oxygen demand which cannot treat problem here which is reduced oxygen supply
what is ranolazine used
alternative option for pts with chronic angina that have failed all other therapies
mechanism of action for ranolazine
blocks sodium current which prevent calcium overload within the cell leading to improved coronary flow
typically Na late inward current lead to Ca inward current via the Na/Ca exchanger –> Ca leads to contraction of myocytes and impaired relaxation hence worsening the ischemia
adverse effects of ranozaline
QT prolongation (increases ventricular depolarization) nausea, vomiting, dizziness, constipation
contraindication of ranozaline
pts with QT prolongation –> risk of torsades de pointes and ventricular arrhythmias
treatment of acute attack of stable angina
nitroglycerin or rest
maintenance therapy for stable angina
- long acting nitrates plus beta blockers are preferred
- CCBs when beta blocker not successful or contraindicated
- ranozaline when nitrates, beta blocker, and CCBs not successful
-aspirin and aggressive cardiovascular risk reduction should be part of maintenance therapy
tx for acute attack of unstable angina (usually occurs between stable angina and MI)
nitroglycerin or rest
long term maintenance of unstable angina
nitroglycerin and beta blockers
drug used for symptomatic treatment of variant prinzmetal angina
nitroglycerin and calcium channel blockers
