M3 L3: antianginals Flashcards
(27 cards)
Coronary artery disease (CAD)
- narrowing or blocking of coronary arteries -> decreased blood flow -> decreased O2 supply to the heart
manifestations of CAD
- asympt
- angina pectoris
- myocardial infarction (MI)
- complications: HF, dysrhythmias, etc
- sudden death
angina pectoris
sudden onset chest pain due to myocardial ischemia
types of angina
- typical (exertional)
- chest pain w exertion
- due to coronary obstruction
- 2 patterns: stable, unstable (more dangerous -> MI) - variant (prinzmetal’s)
- chest pain at rest
- due to coronary vasospasm
factors affecting anginal pain
- precipitating factors: exertion, stress, heavy meals. cold weather
- relieving factors: rest, nitrates
treatment of angina
rest
antianginal drugs
rationale:
- maintain the balance btwn O2 supply and demand
antianginal drugs
- organic nitrates
- β blockers
- calcium channel blockers
vasodilators: nitrates, calcium blockers
cardiac depressants: calcium blockers, beta-blockers
organic nitrates
- esters of nitric oxide (NO)
- short acting: glyceryl trinitrate (= nitroglycerin - GTN)
- long acting: isosorbide dinitrate, isosorbide mononitrate
mechanism of action of treatments for angina
- nitrates ->reduction-> nitric oxide (NO) -> increased GC -> converts GTP -> cGMP -> increased PKG -> decreased intracellular Ca2+ ->
- relaxation of smooth muscles of BV ->
- vasodilation - venous, coronary, arteriolar
venous dilation
decreased
- venous return (preload)
- cardiac output (CO)
- myocardial work
- myocardial O2 demand
coronary dilation
increased
- blood supply to heart
- perfusion
- O2 supply to ischemic myocardium
arteriolar dilatation
decreased
- peripheral resistance (afterload)
- bp
adverse effects of angina treatments
- headache
- flushing
- hypotension
- tachycardia
- dizziness
- methemoglobinemia
- tolerance!
angina drug tolerance
due to continuous exposure
prevention: nitrate-free periods (overnight)
monday disease!
what happens when nitrates are mixed w PDE5 (ex: sildenafil) decrease
severe hypotension
rapid onset routes of administration
sublingual tablets
oral spray
IV
slow onset routes of administration
oral tablets
ointment
transdermal patch
what route of administration for GTN
any route except oral
how do you prepare isosorbide dintrate
sublingual or oral tablets
isosorbide monontrate
oral tablets
mechanism of action for calcium channel blockers
- block L-type voltage-gated Ca2+ channels
- prevent Ca2+ flow into:
1. vascular smooth muscles -> vasodilation - arteries rather than veins
- coronaries are particularly sensitive
2. cardiomyocytes - decreased cardiac contractility
- (-‘ve inotropic) -> decreased CO
classes of CCB
- dihydropyridine
- more vascular selective (ex: nifedipine) - phenylalkylamine
- more myocardial selective (ex: verapamil) - benzothiazepine
- balanced (ex: diltiazem)
adverse effects of CCB
- myocardial depression (verapamil, diltiazem)
- hypotension (nifedipine)
- changes in heart rate (increased HR [nifedipine], decreased HR [verapamil, diltiazem])
- flushing
- ankle edema
- headache
therapeutic indication for angina
diltiazem, verapamil
