Cardiovascular System

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1 Therapeutic Agents for the Lecture 04 Therapeutic Agents for the Cardiovascular System Cardiovascular System Chapter 18 1

2 Anatomy of the Cardiovascular System OBJECTIVES Describe the major components of the cardiovascular system. 2

3 Location and Anatomy of the Heart Located in chest cavity between the lungs Large muscle that: Initiates systemic arterial pulse waves Causes blood to circulate throughout body Supplies body with nutrients and oxygen 3

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5 Location and Anatomy of the Heart (cont d) Arteries are large transport tubes extending from the heart Arterioles are smaller tubes Capillaries are very small tubules that exchange oxygen and nutrients Coronary arteries are the vessels responsible for supplying oxygen to the heart muscle. 5

6 Anatomy of the Heart From Gerdin J: Health careers today, ed 5, St Louis, 2012, Mosby 6

7 The Heart Normal heartbeat: 60 to 100 beats/min Size: Person s fist Pericardium: Connective tissue surrounding heart; anchored by ligaments to chest wall and diaphragm not a layer of the heart wall Three main layers: Endocardium, myocardium and epicardium 7

8 Oxygenation Heart has two sides and four chambers right atrium, right ventricle, left atrium, and left ventricle Heart circulates blood through body delivering oxygen, and nutrients to cells, tissues, and organs Superior and inferior vena cava returning blood to the heart 8

9 Oxygenation (cont d) Superior vena cava brings blood from upper portion of body Inferior vena cava brings blood into heart from lower portion of body Blood travels through right atrium to right ventricle 9

10 Blood Oxygenation 10

11 Oxygenation (Cont.) Right ventricle contracts sends deoxygenated blood to pulmonary arteries then to lungs where blood is oxygenated Left atrium receives oxygenated blood from lungs via pulmonary veins Left ventricle contracts blood sent to aorta 11

12 Circulation of Blood Through the Body 12

13 Cardiac Conduction System Cardiac conduction system provides electrical charge that makes heart pump It is run by two nodes: Sinoatrial (SA) node Upper right atrium wall Sends signal to AV node in septum between right atrium and right ventricle, then throughout muscle fibers Atrioventricular (AV) node From the atrioventricular node the impulse goes to the ventricles to initiate a ventricular beat by stimulation of the bundle branches and Purkinje fibers 13

14 The Cardiac Cycle Cardiac cycle is series of events that occur for one complete heartbeat There are two sequences: Systole Contraction phase Diastole Relaxation phase 14

15 Regulation of the Heart Parasympathetic and sympathetic branches of ANS have opposite effects on heart rate Norepinephrine and epinephrine released during exercise increase heart rate Blood pressure: Force exerted by blood against inner blood vessel walls Cardiac output (CO): Increase in CO means increased blood pressure and flow Increased blood volume may cause increased blood pressure BP expressed as systolic pressure over diastolic pressure 15

16 Peripheral Resistance Peripheral Resistance: Resistance to blood flow due to blood viscosity and amount of force needed Vasoconstriction: Decreased blood vessel diameter Vasodilation: Increased blood vessel diameter Hormones important in regulating blood pressure In low pressure, kidneys release renin; enzyme reactions create angiotensin II Hormones increase sodium and water retention in kidneys Fluid retention leads to increased blood volume (reninangiotensin-aldosterone system) 16

17 herapeutic Agents for the Cardiovascular System OBJECTIVES 1. List the primary symptoms of conditions associated with dysfunction of the cardiovascular system. 2. Recognize drugs used to treat the conditions associated with the cardiovascular system discussed in this chapter. 3. Write the generic and trade names for the drugs discussed in this chapter. 4. List appropriate auxiliary labels when filling prescriptions for drugs discussed in this chapter. 17

18 Common Medication Classes Used to Treat Cardiac Conditions ABCD is the mnemonic for A. Angiotensin-Converting Enzyme (ACE) inhibitors Helps reduce blood pressure by dilating arteries. B. Beta-blockers Blocks both norepinephrine and epinephrine from binding to beta-adrenergic receptors. This reduces the heart rate which can help lower BP and regulate heartbeat in people with tachycardia. C. Calcium channel blockers Act by reducing the calcium intake of the heart muscle and the blood vessels. D. Diuretics Classification not used in the treatment of hyperlipidemia An agent that increases urine output and excretion of water form the body. 18

19 Common Medication Classes Used to Treat ACE inhibitors: Cardiac Conditions (cont d) Reduce blood pressure by dilating arteries End in -pril Side effect dry, hacking cough Angiotensin II receptor antagonists: Also known as angiotensin II receptor blockers [ARBs] Very similar to ACE inhibitors; works by inhibiting angiotensin to reduce blood pressure End in -artan 19

20 Common Medication Classes Used to Treat Cardiac Conditions (Cont.) Beta blockers: Block norepinephrine and epinephrine, which reduces heart rate End in -olol Calcium channel blockers: Reduce calcium intake of the heart, which decreases blood pressure due to vasodilatation 20

21 Conditions Affecting the Cardiovascular System Heart conditions include: Hyperlipidemia Lipitor, Niaspan ER, and Questran Hypertension Myocardial infarction (MI) Prehypertensive state Thrombosis Drug Questran binds to bile acids in the GI tract, preventing reabsorption to lower cholesterol levels. 21

22 Hypertension Hypertension is persistent high blood pressure Silent killer ; there are no obvious signs of its presence Is result of various factors, such as diseased heart or kidneys not working properly, causing edema Risk factors include: genetics, age, gender, race, lifestyle, diet, anxiety, alcohol consumption, and sodium intake 22

23 Hypertension (Cont.) High blood pressure: Systolic more than 140 mm Hg Diastolic readings: Three categories of hypertension Systolic readings: Two categories of hypertension Four-step approach based on severity of condition Diet with or without medication (leading contributors of hypertension include food high in fat, sodium, tyramine) To reduce hypertension: Reduce salt and alcohol intake, exercise, quit smoking 23

24 Treatment of Hypertension Main agents: Antihypertensives: Methyldopa Doxazosin Clonidine Terazosin Prazosin Other agents: Diuretics and Vasodilators If medication required, diuretics are initial drug therapy Other agents: Angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and calcium channel blockers 24

25 Hypotension Low blood pressure Orthostatic hypotension: Standing up quickly from lying position Side effects: Syncope (fainting), vertigo (dizziness) fainting upon standing Treatment: Medication adjustment, increased salt intake, drink more water, move/stand slowly Drug treatment: Fludrocortisone (which increases blood volume) Midodrine (which raises blood pressure) 25

26 Hyperlipidemia Increase of lipids in bloodstream; precursor to atherosclerosis (hardening of arteries). Purpose of cholesterol: Vital for making steroid hormones and cell membranes Ingestion of high fat foods: Too much cholesterol and fatty acids; body cannot eliminate 26

27 Hyperlipidemia (Cont.) Fatty substances float through bloodstream; latch onto large arteries and middle-sized arteries of heart and brain; body cannot eliminate Generic test given for cholesterol levels Low is below 200 mg/dl Borderline high is 200 to 239 mg/dl 27

28 Hyperlipidemia (Cont.) High: 240 mg/dl In-depth look: Low-density lipoprotein (LDL) High-density lipoprotein (HDL) Very-low density lipoproteins (VLDLs): Precursor to LDL 28

29 Factors Influencing Hyperlipidemia Family history, lifestyle habits, and patient s personal medical history Good cholesterol HDL: Transporters of fat from tissues Bad cholesterol LDL: Carry around lipids (fat) that can attach to artery walls, causing atherosclerosis 29

30 Drug Treatment for Hyperlipidemia Antihyperlipidemics Bile acid sequestrants Hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors ( statins ) Fibrates Statins raise HDL and lower LDL and VLDL Statins may be toxic to Liver Niacin added to other drug therapies some formulations of Niacin cause flushing 30

31 Coronary Artery Disease Coronary artery disease (CAD) is associated with atherosclerosis, the buildup of lipids (cholesterol) in arteries Atherosclerosis is linked to high blood pressure Fatty deposits build up, thrombus forms, and artery blocked: Results in myocardial infarction Nitrates, beta-blockers, calcium channel blockers (CCBs), and bile acid sequestrants Nitrates are used to treat angina, reduce the workload of the heart and dilate the arteries 31

32 Coronary Artery Disease (Cont.) Risk factors: Hypertension Age, gender, race Genetics Factor alterations: Fatty diet No exercise Smoking Stress 32

33 Angina Pectoris Three types: Classic Variant Unstable Classic angina: Short ischemic episodes of pain and mild deficiency of oxygen Pain: Chest, neck, arms, teeth, jaw Can occur after exercise or excessive activity Decreased blood flow to heart results in chest pain, minor to severe 33

34 Angina Pectoris (Cont.) Variant angina: Spasms of coronary artery Very painful and may occur even at rest Unstable angina: History of anginal attacks Obstruction of arteries, increases over time 34

35 Treatment of Angina Pectoris Treatment: Nitrates, Nitroglycerin (NTG) Lifestyle changes Surgery to bypass blockage NTG ointment is available in 1g,30g,and 60g. Doses are measured in half (½) to 2-inch segments similar to toothpaste. NTG ointment is applied to the chest skin. 35

36 Drug Treatment for Angina Pectoris Common agents include nitrates, calcium channel blockers, beta-blockers Most prescribed are nitroglycerin (sublingual tablets) Dosage forms for nitroglycerin include capsules, topical patches, paste, sublingual spray Sublingual tablets and injectable forms used in emergency only 36

37 Nitrates: Drug Action Vasodilators dilate arteries to permit increase of blood flow through heart muscle They reduce workload of heart Isosorbide and nitroglycerin: Treat angina Sublingual tablets: Very effective; rapid absorption; bypass gastrointestinal system; enter directly into bloodstream Drug not inactivated by stomach acid Faster onset of action 37

38 Nitrates: Drug Action (Cont.) Nitroglycerine is only good for 6 months after opening container Must be kept in dry area in light-protected glass container to prevent breakdown Patches, applied once daily, are taken off at bedtime Ointment tubes available in 60 g, 30 g, and 1 g (unit dose) Translingual spray: Patient sprays one or two metered doses under tongue with maximum of three sprays per 15-minute period 38

39 Thrombotic Events Formation of a clot blocking blood flow is thrombosis Some clots are bad (overactive clotting mechanism) Embolus: Clot broken away from thrombus, lodged and creating blockage Treatment: Supportive stockings, standing/walking on a regular basis to facilitate circulation Drug treatment: Anticoagulants or thrombolytics Anticoagulant: Warfarin interferes with vitamin K synthesis 39

40 Myocardial Infarction and Transient Ischemic Attack Blood flow is entirely blocked because of thrombus, results in death of that part of the heart A massive infarction permanently weakens heart Treatment: Cardiac rehab, dietary changes; betablockers, ACE inhibitors Transient ischemic attack (TIA): Short period of reduced oxygenation to brain; can last a few minutes or occur throughout day Treatment: Reduce risk factors; antiplatelet medication, anticoagulants; surgery (MI) also known as a heart attack 40

41 Arrhythmia Irregular heartbeats: Dysrhythmias Pacemaker: SA node Chemical or oxygen imbalance influences pacemaker, resulting in dysrhythmias Short-term treatment: Emergency room Long-term treatment: Medications 41

42 Drug Treatment for Arrhythmias Agents: Work on conduction system to induce regular heartbeats Lidocaine: Used in emergency situations after MI and other conditions Quinidine sulfate & Procainamide: Decrease speed of conduction system; used for tachycardia, and other arrhythmias 42

43 Heart Failure Heart failure (HF) is a progressive disease. Therefore there is no cure. Lanoxin is most commonly prescribed. Digibind prescribed to treat an overdose of Lanoxin Heart cannot pump vigorously, & delivers less blood throughout body Complication: Edema (kidneys retain more fluid) making the heart work harder Most common treatments: Cardiac glycosides: Digoxin Diuretics for edema 43

44 Diuretics Used for Heart Failure Related Edema Thiazides, loop diuretics: Large potassium loss in urine (potassium supplements used) typically used for the treatment of hypertension Diuretics given with agents to decrease effects of sodium retention Example is hydrochlorothiazide (HCTZ) Potassium-sparing diuretics: Triamterene/HCTZ 44

45 Hypertension Patients with hypertension should be aware of decongestants, nonsteroidal anti-inflammatory drugs (NSAIDs) and antihistamines. 45

46 Questions? 46

Therapeutic Agents for the Cardiovascular System

Therapeutic Agents for the Cardiovascular System Chapter 18 1 Location and Anatomy of the Heart Located in chest cavity between the lungs Large muscle that: Initiates systemic arterial pulse waves Causes