Drugs Affecting Cardiac and Renal Systems

1. Drugs Affecting Cardiac and Renal Systems Jan Bazner-Chandler MSN, CNS, C-PNP, RN

2. Positive Inotropic Drugs Chapter 21

3. Inotropic Drugs • Drugs that increase the force of myocardial contractions.

4. Chronotropic Drugs • Drugs that increase the rate at which the heat beats.

5. Dromotropic Drugs • Drugs that accelerate conduction.

6. Heart Failure • Congestive heart failure (CHF), or heart failure (HF), is a condition in which the heart can't pump enough blood to the body's other organs. This can result from • narrowed arteries that supply blood to the heart muscle — coronary artery disease (CAD) • past heart attack, or myocardial infarction (MI), with scar tissue that interferes with the heart muscle's normal work • high blood pressure • heart valve disease due to past rheumatic fever or other causes • primary disease of the heart muscle itself, called cardiomyopathy. • heart defects present at birth — congenital heart defects. • infection of the heart valves and/or heart muscle itself — endocarditis and/or myocarditis

7. CAD

8. Heart Valve Disease

9. Endocarditis

10. Heart Failure • As blood flow out of the heart slows, blood returning to the heart through the veins backs up, causing congestion in the tissues. Often swelling (edema) results. Most often there's swelling in the legs and ankles, but it can happen in other parts of the body, too. Sometimes fluid collects in the lungs and interferes with breathing, causing shortness of breath, especially when a person is lying down.

11. Heart Failure

12. Signs and Symptoms of Heart Failure or HF • Often no symptoms at rest • Dyspnea (difficulty breathing) and fatigue occur with increased activity • Edema of ankles and feet • Distention of jugular veins • In acute cases pulmonary edema – cough and shortness of breath

13. Pitting Edema

14. Distended Jugular Vein

15. Drugs in first-line treatment • Digoxin • Diuretics • ACE Angiotension-converting enzyme inhibitors

16. Cardiac Glycosides • Oldest and most effective group of cardiac drugs. • Comes from the plant “fox glove”.

17. Cardiac Glycosides or Digoxin • Digoxin or Lanoxin is the only commonly used digitalis glycoside.

18. digoxin (Lanoxin, Digitek) • Classification Pharmacologic: digitalis, glycoside • Classification Therapeutic: antiarrhythmic, inotropic

19. Actions • Digoxin improves the pumping ability of the heart • Increases the force of myocardial contraction by inhibiting the Na, K-adenosine triphosphatase, an enzyme in cardiac cell membrane that decreases the movement of sodium out of myocardial cell after contraction. • Calcium enter the cell in exchange for sodium. • The calcium activates the contractile proteins and increased myocardial contractility.

20. Administration • Can be given orally or IV • IV peaks within 10 to 30 minutes • PO peaks within 1 to 2 hours

21. Serum Blood Levels • Maximum drug action occurs when steady tissue concentration has been achieved – takes about 1 week • Loading dose or digitalizing dosage will be higher until the therapeutic level has been reached. • Dosage 0.75 to 1.5 mg every 6 to 8 hours • When adequate levels have been reached than a maintenance dose can be started

22. Maintenance Dose • Dosing is 0.125 – 0.5 mg • Average dose is 0.25 mg • Take daily at same time of day • Give with food or after meals

23. Dosing by mcg/kg in Adults • IV digitalizing dose = 0.6 to 1 mg (10 -15 mcg/kg) given at 50% initially and additional fractions given at 4-8 hour intervals. • PO adults digitalizing dose 0.75 – 1.25 mg (10 – 15 mcg/kg) • PO children digitalizing dose 10 to 15 mcg/kg

24. Nursing Responsibilities • Take apical pulse for one full minute before giving the medication – listen for any irregular heart beats • Specific guidelines for holding the drug and notifying physician • Adults: apical pulse less than 60 • Older child: apical pulse less than 60 • Infant or younger child: apical pulse less than 100

25. Nursing Responsibilities • Notify physician if bradycardia (heart rate less than 60 bpm) or new arrhythmias occur. • Assess for peripheral edema and auscultate lunge for rales/crackles. • Check kidney function since you want to know they can excrete excess digoxin and avoid build up in body.

26. Laboratory Values • Electrolyte imbalance: potassium, calcium and magnesium values need to be monitored • Hypokalemia (low potassium) • Hypomagnesemia (low magnesium) • Both can lead to irregular heart rate.

27. Digoxin Toxicity • Anorexia, nausea, and confusion are symptoms of digoxin toxicity • HR below 60 in adults and 100 in infants and small children • Digoxin should be discontinued by MD only– takes about 1 week for drug to be eliminated from the body.

28. Evaluation of Effectiveness • Increased urinary output • Decreased edema • Decreased shortness of breath, dyspnea and crackles • Decreased fatigue • Improved peripheral pulses, skin color and temperature • Serum digoxin levels 0.5 to 2 ng/mL

29. digoxin Overdose • digoxin immune Fab or DigiFab • Therapeutic classification: antidotes • Pharmacologic classification: antibody fragments • Indications: serious life-threatening over dosage with digoxin. • Action: An antibody produced in sheep that binds anti-genetically to unbound digoxin in serum. • Therapeutic effect: Binding and subsequent removal of digoxin, preventing toxic effects in overdose.

30. Antianginal Drugs Chapter 23

31. Coronary Arteries • Arteries that deliver oxygen to the heart muscle.

32. Coronary Arteries

33. Angina Pectoris • Chest pain occurring when the heart’s supply of blood carrying oxygen and energy-rich nutrients is insufficient to meet demands of the heart.

34. Ischemia • Poor blood flow to an organ • Ischemic heart disease = poor blood flow to heart • Myocardial infarct = damage done to heart muscle after an ischemic event

35. Angina • Angina pectoris is a clinical symptoms characterized by episodes of chest pain. • There is deficit in myocardial oxygen supply (myocardial ischemia) in relation to myocardial oxygen demand. • Pain can be caused by coronary vasospasm

36. Angina

37. Angina

38. Classification of Angina • Class I: ordinary physical activity does not cause angina – strenuous activity only. • Class II: angina occurs with walking or climbing stairs rapidly or up hill. • Class III: marked limitation in ordinary daily activity. • Class IV: anginal symptoms may be present at rest.

39. Antianginal Drugs • Nitrates are used to treat and prevent attack of angina. • Only nitrates can be used in the acute treatment of angina pectoris. • Calcium channel blockers and beta blockers are used prophylactically or in long-term management of angina.

40. nitroglycerin • Most widely used nitrate • Antianginal • Used to relieve acute angina

41. nitroglycerine • Classification Pharmacologic: nitrates • Classification Therapeutic: antianginals

42. nitroglycerine • Action: Increases coronary blood flow by dilating coronary arteries and improving collateral flow to ischemic regions. Decreases left ventricular end-diastolic pressure and left ventricular end-diastolic volume. Reduces myocardial oxygen consumption. • Therapeutic effects: • Relief or prevention of anginal attacks. • Reduction of blood pressure.

43. Dosing • Oral dosage is rapidly metabolized in the liver and only small doses reach the systemic circulatory system • For more effective absorption drug is given: • Sublingually – under the tongue – acts in 1 to 3 minutes • PO: sustained-released tablet • Transdermal ointments – applied on hairless area on back, chest or upper arm • Patches – takes a 40 minutes to an hour to start working

44. Sublingual Nitroglycerine

45. Sublingual Administration • Tablet should be held under tongue until dissolved. Avoid eating, drinking, or smoking until tablet is dissolved. • Acute anginal attacks: • Advise patient to sit down. • Relief should occur in 5 minutes • May be repeated every 5 minutes for 3 doses. • If no relief call 911.

46. Sustained Released Tablet

47. Sustained Released Tablet • Administer dose 1 hour before or 2 hours after meal with a full glass of water for faster absorption. • Note: Sustained released preparations should be swallowed whole, do not crush, break or chew.

48. Nitroglycerine Patch

49. Nitroglycerin Patch • Place the patch on a hairless area of chest or upper arm each day. • Move patch to a different place on your body each day to prevent skin irritation. • Remove the patch for 8 to 12 hours each night and put on a fresh patch each day. • Do not leave on all the time. • Remove for defibrillation

50. Nitroglycerine Ointment