Vasodilators and the Angina pectoris Flashcards
What are the 3 drug classes mainly used for angina
nitrates
CCBs
Beta blockers
How does medication help with angina
decreases how much oxygen the heart needs by decreasing one or more of these things: heart size, heart rate, blood pressure, and contractility
Nitrates and calcium channel blockers may help by angina by___ and help variant angina by ____
causing a redistribution of coronary flow and increase oxygen delivery to ischemic tissue
In variant angina, they help by reversing coronary artery spasm.
Nitro: What are the 3 considerations
store in an air tight container due to loss of potency
may develop tolerance
due to low bioavailability, sublingual route is preferred to achieve rapid response; sustained effect is limited to 15-30 minutes
Nitro: must be stored in
air tight container due to loss of potency
Nitro: patient may develop
tolerance
Nitro: due to low bioavailability,
sublingual route is preferred to achieve rapid response; sustained effect is limited to 15-30 minutes
Isosorbide: 2 considerations
you might develop tolerance
isosorbide mononitrate is the active metabolite of isosorbide dinitrate and has 100% bioavailability.
Whats the main target of nitrates
vascular smooth muscle
All 7 Effects of Nitrates:
- Veins relax so you have less ventricular preload
- Pulmonary vascular pressures decrease
- Heart size is reduced.
- In the absence of heart failure, cardiac output is reduced.
- In heart failure, preload is often abnormally high; the nitrates and other vasodilators, by reducing preload, may have a beneficial effect on cardiac output in this condition
- The indirect effects of nitroglycerin are tachycardia and increased cardiac contractility.
- Retention of salt and water, especially with intermediate- and long-acting nitrates. These compensatory responses contribute to the development of tolerance.
Effects of Nitrates: Veins relax so you have
less ventricular preload
Effects of Nitrates: Pulmonary vascular pressures
decrease
Effects of Nitrates: Heart size is
reduced
Effects of Nitrates: In the absence of heart failure,
cardiac output is reduced.
Effects of Nitrates: In heart failure,
preload is often abnormally high; the nitrates and other vasodilators, by reducing preload, may have a beneficial effect on cardiac output in this condition
Effects of Nitrates: The indirect effects of nitroglycerin are
tachycardia and increased cardiac contractility.
Effects of Nitrates: Retention of
salt and water, especially with intermediate- and long-acting nitrates. These compensatory responses contribute to the development of tolerance.
4 Adverse effects of Nitrates
orthostatic hypotension
tachycardia
headache
tolerance
Angina of effort
myocardial oxygen requirement increases, especially during exercise, and coronary blood flow does not increase proportionately
Not enough blood flow in the presence of CAD, also known as classic angina
Nitrates can be used for 3 types of Angina
Angina of effort
Variant angina
Unstable angina
Variant angina
sometimes you have blood vessel spasms, usually associated with underlying atheromas, can also cause significant myocardial ischemia and pain (vasospastic or variant angina). Vasospastic angina is also called Prinzmetal angina.
Unstable angina
acute coronary syndrome, is said to be present when episodes of angina occur at rest and there is an increase in the severity, frequency, and duration of chest pain in patients with previously stable angina. Increased coronary artery resistance or small platelet clots occurring in the vicinity of an atherosclerotic plaque. Associated with increased risk of MI
All of the ways that CCBs help with angina:
- Decreasing myocardial contractile force, which reduces myocardial oxygen requirements
- They decreases arterial and intraventricular pressure by blocking arterial smooth muscle
- Stress on the left ventricular wall decreases
- They stop coronary artery spasm
- The sinus node rate is decreased
- AV node conduction slows down
- Verapamil and diltiazem also have their own special way, which is that they have an antiadrenergic effect
CCBs help with angina by decreasing ___ ___ ___, which reduces myocardial oxygen requirements
myocardial contractile force
CCBs help with angina by decreasing ___ and ___ ___ by blocking arterial smooth muscle
arterial and intraventricular pressure
CCBs help with angina by decreasing stress on the ___ wall
ventricular wall
CCBs help with angina by stopping ___ ___ spasm
coronary artery spasm
CCBs help with angina by the ___ node rate is ____
sinus node rate is decreased, and so is the AV node
CCBs help with angina, verapamil and diltiazem spefically help because
they have an antiadrenergic effect
Is it possible to have so much calcium that the CCBs don’t work?
It’s possible, but it’s unlikely because the levels of calcium would have to be super high.
Sympathomimetics can increase calcium getting into the cells, which obviously isn’t good for CCBs
calcium channel blockers are ___ active agents
orally
CCBs have ___ ___-pass effect
high first-pass effect
CCBs have ____ ____ ____ binding
high plasma protein binding
CCBs have ____ metabolism
extensive metabolism
What are the three things that characterize CCBs
high first-pass effect
high plasma protein binding
extensive metabolism
Verapamil and diltiazem routes
oral and IV
3 Clinical Uses of Verapamil and diltiazem
arrhythmias (AF and atrial flutter)
Unstable angina
Postinfarction angina
Clinical Uses of Verapamil and diltiazem: arrhythmias such as
AF and atrial flutter
What should you know about CCBs for treating unstable angina
immediate-release short-acting calcium channel blockers can increase the risk of adverse cardiac events and therefore are contraindicated
Clinical Uses of diltiazem: Postinfarction angina
Diltiazem can decrease the frequency of and may be used for patients with non–Q-wave myocardial infarction
What in general should you know about Adverse Effects of CCBs
Adverse effects are rare, but can include really bad things:
serious cardiac depression, including bradycardia, atrioventricular block, cardiac arrest, and heart failure
They can also cause less serious stuff like edema and constipation with verapamil
Clinical use for beta blockers
Stable angina
How do beta blockers help with stable angina
decreased heart rate, blood pressure, and contractility, which means there’s less oxygen demand.
Also, since the heart is going slower there is more time for perfusion.
5 beta blocker Contraindications
asthma severe bradycardia AV block bradycardia-tachycardia syndrome Severe unstable left ventricular failure
Adverse effects of Beta blockers
impaired exercise tolerance insomnia, unpleasant dreams, worsening of claudication, and erectile dysfunction.
Summary: Stable angina can be treated with
Nitrates
CCBs
BBs
Summary: Vasospastic angina can be treated with
Nitrates
CCBs
Summary: Unstable angina and acute coronary syndrome
Nitrogylcerine
BBs
and for refractory cases CCBs
