1. Chapter 18 Agents that Dilate Blood Vessels

2. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 2 Coronary Vasodilators Used to treat coronary artery disease Coronary artery disease: inadequate delivery of blood, nutrients, and oxygen to the tissues

3. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 3 Chest Pain/Angina When the supply of oxygen and nutrients in the blood is insufficient to meet the demands of the heart, the heart muscle aches.

4. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 4 Vasodilator Drug Agents Three main objectives:  Minimize frequency, duration, and intensity of episodes  Offer few side effects  Prevent myocardial infarction—death

5. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 5 Therapeutic Objectives Increase blood flow to ischemic heart muscle Decrease myocardial oxygen demand (continues)

6. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 6 Therapeutic Objectives Minimize the frequency of attacks Improve the client’s functional capacity Prevent or delay heart disease (continued)

7. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 7 Main Classes Acetylsalicylic acid (ASA) Nitrates Calcium channel blockers Beta blockers Angiotensin II receptor blockers

8. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 8 Nitrates Nitroglycerine  Forms: sublingual, buccal, chewable, tablets, ointments, patches, spray, and intravenous

9. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 9 Nitroglycerine Causes central and peripheral vasodilation  Relaxes smooth muscles Potent dilating effect on coronary arteries Used for prophylaxis and acute treatment of angina

10. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 10 Nitroglycerin Large first-pass effect when taken orally Transdermal—very effective IV form effectively used for:  Hypertension  Congestive heart failure  Ischemic pain, myocardial infarction  Pulmonary edema

11. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 11 Nitrates Example of long-acting nitrate  Isosorbide dinitrate (Isordil) Provides:  Acute relief of angina  Long-term prophylaxis of angina

12. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 12 General Side Effects Headache  Diminish in intensity and frequency with use Tachycardia Postural hypotension Dermatitis Tolerance

13. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 13 Tolerance to Nitrates Long-acting form can become ineffective Solution  Remove patch or cream at night for 8 hours  Take the oral form for 16 hours a day

14. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 14 Interactions Additive hypotension with use of:  Alcohol  Beta blockers  Calcium channel blockers  Phenothiazines

15. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 15 Calcium Channel Blockers Reduces calcium ion influx:  Reduction of myocardial oxygen consumption  Coronary artery dilation Example: verapamil Side effects  Dizziness, flushing, supraventricular arrhythmias

16. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 16 Beta-adrenergic Blocking Agents Block the beta receptors  Reduce heart rate  Reduce contractility  Reduce blood pressure Example  Atenolol Side effects  Flushing, bradycardia, and bronchospasm

17. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 17 Peripheral Vasodilators Angiotensin II receptor blockers  Block adrenergic receptors, or  Direct action  Interfere with epinephrine action Sympathetic nervous system is not stimulated  Result: decreased blood pressure Side effects  Orthostatic hypotension

18. Copyright 2007 Thomson Delmar Learning, a division of Thomson Learning Inc. All rights reserved. 18 - 18 Aspirin Inhibits platelet clumping  Given as a preventive agent  Given when a person is experiencing a myocardial infarction