Drugs for the Tx of Angina Flashcards
Inadequate supply of oxygen to the heart.
Myocardial Ischemia
Where does pain radiate in angina pectoris?
Left shoulder and flexor surface of the arm.
Correlation between the radius of the ventricular walls and oxygen demand.
Greater radius = greater oxygen demand
Autoregulation
The intrinsic ability of an organ to maintain blood flow, even when perfusion pressure is low.
When do we NOT see autoregulation?
During Dilation and Constriction
Three Types of Angina
1) Exertional
2) Vasospastic
3) Unstable
Exertional Angina
Chest pain occurs when you exert yourself (exercise or emotional upset) and is the result of arteriosclerotic plaques reducing blood flow through the heart.
Causes exertional angina.
Coronary artery disease (atherosclerotic plaques in the coronary arteries).
Vasospastic angina.
Pain develops at rest due spasms in the epicardial coronary arteries.
Unstable angina.
Precedes a myocardial infarction.
Occurs at rest or with minimal exertion.
Vascular Capacitance definition.
The ability of a blood vessel to increase the volume of blood it holds without increasing the blood pressure.
Types of angina treated by organic nitrates.
Exertional, vasospastic, and unstable.
How do organic nitrates work?
Relaxes vascular smooth muscle by release NO, a potent vasodilator.
Vasodilatory potency of Nitroglycerin.
Veins > Arteries > Arterioles.
How does Nitroglycerin affect myocardial oxygen demand?
It reduces myocardial oxygen demand because it vilates the veins, causing:
1) Decreased venous return to the heart (decreased preload)
2) Ventricular wall tension and oxygen demand are reduced.
Nitroglycerin sometimes causes a reflex _______.
Tachycardia because it causes the arteries to vasodilate, and this causes a drop in BP, so the body tries to compensate by increasing the BP.
Which heart muscle is most vulnerable to ischemia in exertional angina?
Endocardium.
Redistribution pattern of blood flow in exertional angina?
From Epi to endocardium
Adverse effects of organic nitrates.
1) Postural Hypotension
2) Reflex tachycardia
Solubility of organic nitrates (IMPORTANT)
LIPID SOLUBLE.
3 Routes of Administration for organic nitrates:
1) Sublingual
2) Topical
3) Oral
When to use sublingual nitrates?
Exertional or Vasospastic angina, or as prophylaxis if you’re doing an activity that can cause an anginal attack.
Cool thing about sublingual nitrates and metabolism.
They bypass the liver and go directly to the bloodstream.
Onset of action for sublingual nitrates.
1-5 minutes.
Gets in the bloodstream in 1 minute.
Has maximal effect in 5 minutes.
Effects last for 20 minutes.
Absorption time for topical nitrates.
3-18 hours
Metabolism of oral nitrates.
They get metabolized in the liver, so may need higher doses to get an effect.
Tolerance is most likely to occur with which form of organic nitrates?
Oral
If it ends in “olol,” it’s a __________.
Beta blocker
If it ends in “pril,” it’s a _________.
ACE inhibitor
Beta blockers are used to treat what kinds of angina?
Exertional and Unstable.
Do NOT use beta blockers to treat this kind of angina.
Vasospastic
Effects of propanolol on myocardial oxygen demand.
1) Decreases CO and heart rate.
2) Decreases afterload.
3) Increases preload/end diastolic volume - thus increasing oxygen demand.
4) OVERALL net effect is that it decreases oxygen demand.
Propanolol effects on coronary vessels.
Reduced CO and HR lead to decreased blood to the heart through the coronary vessels, so they constrict as a result.
Increased coronary vascular resistance.
Why are Propanolol (Beta blocker) and Nitroglycerin combined to treat angina?
Because they block out each other’s adverse effects:
1) Propanolol can increase end diastolic volume, which is counteracted by Nitroglycerin, which reduces cardiac preload by causing vasodilation.
2) Nitroglycerin can cause reflex tachycardia, which is counteracted by the beta blocker (reduces sympathetic CO and HR).
3 drugs that are calcium channel blockers.
Nifedipine
Verapamil
Diltiazem
Calcium channel blockers are used for what type of angina?
ALL types!
MOA of Calcium Channel blockers.
Reduce Ca2+ influx through SA and AV nodes, ventricular muscle, and vascular smooth muscle.
Effects of Ca2+ channel blockers on myocardial oxygen demand.
1) Cause vascular smooth muscle to relax, causing vasoDILATION, which decreases afterload.
2) Has no effect on preload.
3) Can reduce contractility and heart rate.
4) Vasodilation causes a reflex Tachycardia.
5) Dilates coronary arteries and arterioles to increase blood to the heart.
Adverse effects of Calcium channel blockers.
1) Hypotension and edema from excessive vasodilation.
2) Bradycardia and Congestive Heart Failure.
3) Gingival Hyperplasia
Dealing with an acute anginal attack in the dental office.
1) Stop dental tx.
2) Put pt in upright 45 degree angle position.
3) Give sublingual Nitroglycerin tablet.
4) Give oxygen 6 L/min
5) Give another dose of Nitroglycerin if symptoms don’t go away after five minutes.
6) Repeat and call for medical help.
