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• These arteries are particularly susceptible to the formation of the cholesterol filled plaques which reduce coronary blood flow (ischemia).
• Angina pectoris (chest pain) is a result of insufficient blood flow/oxygen delivery to the myocardium.
II. Classifications of Angina
• The 3 major types of angina pectoris are exertional angina, variant(Prinzmetal's) angina, and unstable angina.
A. Exertional angina
• Exertional angina is the most common type. It is usually found in people with coronary artery disease.
• There is a regular pattern to this type of angina, it is predictable in its frequency and duration.
• It often occurs during physical exertion, or emotional excitement, both increase the oxygen demand of the heart.
B. Variant angina
• This is less common and unpredictable. It can occur at any time, even while sleeping.
C. Unstable angina
• Unstable angina is a very dangerous condition that generally occurs in patients with advanced CAD.
III. Symptoms of angina
• classic presentation: sharp pain in the heart region, often moving to the left side of the neck and lower jaw, and down the left arm
IV. Treatment for angina
• 3 major classes of drugs are used to treat angina:
• nitrates
• beta blockers
• calcium channel blockers
• Beta blockers and calcium channel blockers are used in long term management (as are some nitrates).
A. Nitrates
• Main function of these drugs is to produce vasodilation of systemic veins and arteries.
• With venodilation, the amount of blood returning to the heart (preload) is reduced and the chambers contain less blood
• Nitrate drugs all contain one or more nitrate group.
• This group is released from the drug and converted by enzymes in blood vessels to nitric oxide (NO).
a. Isosorbide mononitrate (ISMO, Imdur)
• ISMO: 20 mg tablets; 30 minute onset; 6 – 8 hour duration
• Indur: 30, 60, or 120 mg extended-release tablets; 30 minute onset; 12 hour duration
b. Isosorbide dinitrate (Isordil, Sorbitrate)
• Isordil: 2 ½, 5, or 10 mg sublingual tablets with an onset of 2 – 5 minutes and a duration of 2 – 3 hours; or 5,10, 20, 30, 40 mg tablets with an onset of 30 minutes and a duration of 4 – 6 hours
c. Nitroglycerin (many forms)
• Nitrostat: 0.3, 0.4, 0.6 mg sublingual tablets with an onset of 1 – 3 minutes and a duration of 30 minutes
• Nitrolingual Pump Spray: 0.4 μg per spray with an onset of 1 – 3 minutes and a duration of 30 minutes
• Nitrobid IV: 5 μg/min IV infusion with an onset of 1 – 3 minutes, duration generally until infusion is stopped
• Nitrobid 2% ointment: each inch of ointment squeezed from the tube contains about 15 mg nitroglycerin; onset of 30 minutes and a duration of 4 – 8 hours
• Transderm-Nitro: 0.2 – 0.4 mg/hour transdermal patch; onset of 30 minutes and a duration of 24 hours
• Nitrogard: 1, 2, or 3 mg extended release buccal tablets, onset of 30 minutes and a duration of 6 – 8 hours
B. Beta blockers
• Beta blockers are used in the treatment of angina to reverse the effects of sympathetic activation caused by exercise or physical exertion.
• Recall: sympathetic stimulation results in ↑ heart rate, myocardial contraction and O2 consumption
• Result in less frequent anginal attacks or delayed onset of pain during physical exertion (meaning an increased exercise tolerance)
• All beta-blockers appear to be equally effective in the treatment of angina. Only the following 4 are FDA-approved for the treatment of angina:
• Selective β1 blockers:
• atenolol (Tenormin): 50 – 100 mg
• metoprolol (Lopressor, Toprol): 100 – 400 mg
C. Calcium channel blockers
• These are the preferred drug for treating variant angina.
• Movement of calcium ion into smooth muscle cells lining coronary arteries is necessary for contraction
• Movement of calcium ion into smooth muscle cells lining coronary arteries is necessary for contraction.
• By inhibiting calcium influx, CCB’s produce vasodilation. The dosages used in angina primarily relax arterial smooth muscle, resulting in arteriolar vasodilation.