Anti-Anginal Drugs Flashcards
How are oxygen demand and supply matched up to each other?
Through control of the coronary blood flow - NOT because of increased O2 extraction
When does coronary blood flow occur?
Most of it occurs during diastole
What are factors that contribute to myocardial O2 demand?
Heart Rate
Wall Tension
Contractility
What are the factors that contribute to myocardial O2 supply?
Diastolic Perfusion Pressure
Coronary Resistance
O2 Carrying Capacity
When does myocardial ischemia occur?
When myocardial demand surpasses supply
What is the most common cause of myocardial ischemia?
Atherosclerotic Coronary Artery Disease - often with manifestation of Angina Pectoris
How does severe aortic stenosis cause myocardial ischemia?
It causes high wall tension that can cause ischemia
What is the cause of Prinzmetal’s Angina?
Acute Coronary Vasospasm
What are the actions of nitrate drugs?
Vasodilation
Is the relaxation action of NO endothelium dependent?
No. Relaxation Is ENDOTHELIUM-INDEPENDENT.
Where do most of the actions of nitrates occur?
Systemic circulation - major venodilatory effects
What are the effects of nitrates?
- Decreased venous return
- Reduced LV wall tension
- Reduced after load
- Direct coronary artery vasodilation
Nitrate Indications
Angina Pectoris
Hypertensive Emergencies
Congestive Heart Failure
What are the 2 major nitrates?
Nitroglycerin
Isosorbide Mono/Dinitrate
What is the ROA of nitroglycerin that is often used?
Sublingual
What is the ROA of isosorbide mono/dinitrate that is often used?
Oral
What are that main reasons for use of nitrates in exertion angina?
- Terminate myocardial ischemia
- Prevent exercise induced myocardial ischemia
Nitrate SE
- Orthostatic hypotension
- Reflex tachycardia
- Headache
- Nitrate tolerance
What are Ca channel blockers anti-arrhythmic drugs?
L-type Ca channels regulate cardiac pacemaker activity
Ca Channel Blocker Indications
- Angina Pectoris
- Hypertension
- Arrhythmias
- Hypertrophic Cardiomyopathy
- Raynaud’s Phenomenon
What are the 4 classes of CCBs?
- DIHYDROPYRIDINES
- VERAPAMIL
- DILTIAZEM
- BEPRIDIL
What are examples of dihydropyridines?
– Nifedipine
– Nicardipine
– Amlodipine
Rank the CCB-DHP drugs in order of negative inotropic and chronotropic effects?
– Verapamil>Diltiazem»Nifedipine
Verapamil and Diltiazem SE
– Bradycardia
– Congestive Heart Failure
– Heart Block
– Hypotension
Nifedipine SE
– Reflex Tachycardia (due to arterial vasodilation)
– Peripheral Edema
– Hypotension
What are the actions of cAMP (triggered by beta receptors) in the heart?
• Increased Opening of L-type Ca channels – Inotropy • Increased Reuptake of Ca into SR stores –Inotropy & Lusitropy • Increased Pacemaker Current – Chronotropy • Increased Rate of Conduction – Dromotropy
What is the main effect of beta blockers on the ischemic heart?
Decreases the O2 demand of the heart
Beta Blocker Indications
- AnginaPectoris
- Hypertension
- Arrhythmias
- Dissecting Aortic Aneurysm
- Hyperthyroidism
What are the beta blockers eliminated by the liver?
Propranolol
Carvedilol
Metoprolol
What are the beta blockers eliminated by the kidney?
Atenolol
Nadolol
Sotalol
Ranolazine Actions
Ranolazine partially inhibits fatty acid oxidation, allowing the heart to use more glucose as a fuel by relieving the inhibition on pyruvate dehydrogenase.
Ivabradine MOA
IF current inhibitor (funny current) which inhibits pacemaker activity and slows the heart rate at rest and during exercise.
Ivabradine Indications
Angina
Ivabradine SE
Luminous Phenomena
What is the training effect?
HR and BP are lower at rest after prolonged exercise training
What can be done to minimize nitrate tolerance?
Have nitrate-free intervals
What drugs are useful in treating variant angina?
Nitrates and CCBs
What are the mechanisms by which organic nitrates decrease the severity of myocardial ischemia?
- Vasodilation of coronary arteries
- Venodilation will reduce venous return
How can a beta-blocker increase blood flow to an area of ventricular muscle supplied by a stenotic coronary artery?
Decrease in heart rate increases myocardial O2 delivery - increased diastolic perfusion time, decreased vascular compression.