Drugs to treat angina

1. Drugs to treat angina

2. I. Introduction • Branching off the aorta are the coronary arteries.

3. They deliver blood to the muscular layer of the heart (myocardium).

4. These arteries are particularly susceptible to the formation of the cholesterol filled plaques which reduce coronary blood flow (ischemia).

5. A consequence of coronary artery disease (CAD) and the resulting ischemia is angina.

6. Angina pectoris (chest pain) is a result of insufficient blood flow/oxygen delivery to the myocardium.

7. II. Classifications of Angina • The 3 major types of angina pectoris are exertional angina, variant(Prinzmetal's) angina, and unstable angina.

8. A. Exertional angina • Exertional angina is the most common type. It is usually found in people with coronary artery disease.

9. There is a regular pattern to this type of angina, it is predictable in its frequency and duration.

10. It often occurs during physical exertion,or emotional excitement, both increase the oxygen demand of the heart.

11. With rest, the pain usually diminishes in less than 15 minutes and is relieved by medication.

12. B. Variant angina • This is less common and unpredictable. It can occur at any time, even while sleeping.

13. It is caused by vasospasm of one or more of the coronary arteries.

14. It is relieved by medication.

15. Some individuals may experience both exertional and variant angina.

16. C. Unstable angina • Unstable angina is a very dangerous condition that generally occurs in patients with advanced CAD.

17. It is not unpredictable, as it can occur at any time.

18. It is considered a medical emergency, because it is associated with an increased risk of MI.

19. It requires aggressive treatment with anticoagulant, antiplatelet, and antianginal medications.

20. 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

21. IV. Treatment for angina • 3 major classes of drugs are used to treat angina: • nitrates • beta blockers • calcium channel blockers

22. Of 3 classes of antianginal drugs, only the nitrates are used in the treatment of acute attacks.

23. Beta blockers and calcium channel blockers are used in long term management (as are some nitrates).

24. A. Nitrates • Main function of these drugs is to produce vasodilation of systemic veins and arteries.

25. With venodilation, the amount of blood returning to the heart (preload) is reduced and the chambers contain less blood

26. With less blood to eject cardiac output (afterload) is reduced, thus lowering oxygen demand.

27. This provides relief of both ischemia and pain.

28. 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).

29. NO is a potent, short-acting vasodilator that relaxes vascular smooth muscle.

30. 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

31. 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

32. Sorbitate: 5 or 10 mg chewable tablets with a 30 minute onset and a duration of 2 – 3 hours

33. 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

34. 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

35. 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

36. 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.

37. Recall: sympathetic stimulation results in ↑ heart rate, myocardial contraction and O2 consumption

38. Beta blockers: ↓ heart rate, myocardial contraction and O2 consumption

39. Result in less frequent anginal attacks or delayed onset of pain during physical exertion (meaning an increased exercise tolerance)

40. 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:

41. Selective β1 blockers: • atenolol (Tenormin): 50 – 100 mg • metoprolol (Lopressor, Toprol): 100 – 400 mg

42. nonselective beta blockers: • nadolol (Corgard): 80 – 240 mg • propranolol (Inderal): 80 – 320 mg

43. 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

44. Movement of calcium ion into smooth muscle cells lining coronary arteries is necessary for contraction.

45. By inhibiting calcium influx, CCB’s produce vasodilation. The dosages used in angina primarily relax arterial smooth muscle, resulting in arteriolar vasodilation.

46. CCB’s used in the treatment of angina include: • 1. amlodipine (Norvasc) • 2. diltiazem (Cardizem) • 3. nicardipine (Cardene) • 4. nifedipine (Procardia) • 5. verapamil (Calan, Isoptin)