1. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Agents Pharmacology in Nursing

2. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Definition  Drugs that increase the force of myocardial contraction  Used to treat heart muscle failure  Cardiac glycosides  digoxin  Phosphodiesterase inhibitors ( PDIs)

3. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Failure  The heart is unable to pump blood in sufficient amounts from the ventricles to meet the body’s metabolic needs  Impairs heart’s ability to fill or eject properly  Symptoms depend on cardiac area affected  Left ventricular failure  Right ventricular failure

4. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. What happens when the heart fails?  Weakened heart is unable to pump blood in sufficient amounts  Decrease in CO, decrease tissue perfusion  Compensatory mechanisms help to maintain CO and arterial blood pressure  Renin-angiotensin-aldosterone system activated as a compensatory mechanism  As cardiac output decreases, SNS releases catecholamines which increase HR, contractility & vasoconstriction

5. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. What happens when the heart fails?  As renal perfusion decreases, renin is released by kidney  Vasoconstriction increases SVR, which increases afterload  End result, the failing heart must now work HARDER to pump blood

6. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Failure: Causes  Cardiac defect  Myocardial infarction  Valve deficiency  Defect outside the heart  Coronary artery disease/Hypertension  Pulmonary hypertension  Diabetes  Supraventricular dysrhythmias  Atrial fibrillation  Atrial flutter

7. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc.

8. Treatment of Heart Failure  Block the compensatory mechanisms  Treat underlying conditions  Goal is to decrease SVR, decrease volume,  Increase cardiac output

9. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Glycosides  Originally obtained from Digitalis plant, foxglove  Digoxin is the prototype  Used in heart failure and to control ventricular response to atrial fibrillation or flutter

10. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Glycosides: Mechanism of Action  Increase myocardial contractility  Change electrical conduction properties of the heart  Decrease rate of electrical conduction  Prolong the refractory period Area between SA node and AV node Area between SA node and AV node Result: reduced heart rate and improved cardiac efficiency

11. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Drug Effects: General Terms  Inotropic  Force or energy of muscular contractions  Chronotropic  Rate of the heartbeat  Dromotropic  The conduction of electrical impulses

12. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. How Positive Inotropic Agents Work

13. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Glycosides: Drug Effects  Positive inotropic effect  Increase in force and velocity of myocardial contraction (without an increase in oxygen consumption)  Negative chronotropic effect  Reduced heart rate  Negative dromotropic effect  Decreases automaticity at SA node, decreases AV nodal conduction, and other effects

14. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Glycosides: Drug Effects (cont’d)  Increased stroke volume  Reduction in heart size during diastole  Decrease in venous BP and vein engorgement  Increase in coronary circulation  Promotion of diuresis due to improved blood circulation  Palliation of exertional and paroxysmal nocturnal dyspnea, cough, and cyanosis

15. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Glycosides: Indications  Heart failure  Supraventricular dysrhythmias  Atrial fibrillation and atrial flutter

16. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Heart Failure

17. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Atrial Fibrillation/Flutter

18. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiac Glycosides: Adverse Effects  Digoxin (Lanoxin)  Very narrow therapeutic window  Drug levels must be monitored  Low potassium levels increase its toxicity  Electrolyte levels must be monitored

19. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Digoxin: Adverse Effects  Cardiovascular  Dysrhythmias, including bradycardia or tachycardia  CNS  Headaches, fatigue, malaise, confusion, convulsions

20. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Digoxin: Adverse Effects (cont’d)  Eye  Colored vision (seeing green, yellow, purple), halo vision, flickering lights  GI  Anorexia, nausea, vomiting, diarrhea

21. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Digoxin Toxicity  digoxin immune Fab (Digibind) therapy  Hyperkalemia (serum potassium greater than 5 mEq/L) in a digitalis-toxic patient  Life-threatening cardiac dysrhythmias  Life-threatening digoxin overdose  Therapeutic drug level= 0.5 – 2 ng/ml

22. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Conditions That Are Predisposing to Digoxin Toxicity  Hypokalemia  Use of cardiac pacemaker  Hepatic dysfunction  Hypercalcemia  Dysrhythmias  Hypothyroid, respiratory, or renal disease  Advanced age

23. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Dosing Digoxin  Adult Digitalizing Dose: PO or IV : 1-1.5 mg/day (4 doses) Usual maintenance dose 0.125 mg- 0.5 mg day

24. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Phosphodiesterase Inhibitors Work by inhibiting the enzyme phosphodiesterase  Results in:  Positive inotropic response  Vasodilation  Two drugs (inodilators)  Inamrinone (Inocor) and milrinone (Primacor)

25. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Phosphodiesterase Inhibitors: Indications  Short-term management of heart failure  Given when patient has not responded to treatment with digoxin, diuretics, and/or vasodilators  Often given as weekly 6-hour infusions  Improved quality of life  Decreased readmissions for heart failure episodes

26. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Phosphodiesterase Inhibitors: Adverse Effects  Inamrinone (Inocor)  Thrombocytopenia, most worrisome  Dysrhythmia, nausea, hypotension  Elevated liver enzymes with long-term use  Milrinone (Primacor)  Dysrhythmia, mainly ventricular  Hypotension, angina, hypokalemia, tremor, thrombocytopenia

27. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Cardiostimulatory Drugs  Enhance cardiac function by:  Increasing heart rate  Increasing myocardial contractility  Positive Inotrop

28. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-adrenoceptor agonists  Sympathomimetic drugs that bind to beta receptors located in cardiac nodal tissue, conducting tissue  Beta-1 & beta-2 adrenoceptor activation stimulates heart rate & contractility  Net effect: Increase in cardiac output  Used to treat heart failure, cardiogenic and circulatory shock

29. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Agonists Cardiac Effects  Increase contractililty  Increase heart rate  Increase conduction velocity

30. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Beta Agonists Vascular & Other Effects  Smooth muscle relaxation  Bronchodilatation  Hepatic glycogenolysis  Pancreatic release of glucagon  Renin release by kidney

31. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Beta-Agonist Drugs  Epinephrine  Norepinephrine (Levophed)  Dopamine  Dobutamine  Isoproterenol

32. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Major Side Effects  Arrhythmias  Increase myocardial demand for oxygen  Increase in heart rate  Can precipitate angina

33. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. B-type natriuretic peptide  New class  Nesiritide ( Natrecor)  Synthetic recombinant version of B-type natriuretic peptide  Vasodilating effects on arteries and veins  Used in ICU setting as last alternative

34. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications  Assess history, drug allergies, contraindications  Assess clinical parameters, including:  BP  Apical pulse for 1 full minute  Heart sounds, breath sounds

35. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications (cont’d)  Assess clinical parameters (cont'd)  Weight, I&O measures  EKG  Serum labs: potassium, sodium, magnesium, calcium, renal and liver function studies

36. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications (cont’d)  Before giving any dose, count apical pulse for 1 full minute  For apical pulse less than 60 or greater than 120 beats/minute  Hold dose  Notify prescriber

37. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications (cont’d)  Hold dose and notify prescriber if patient experiences signs/symptoms of toxicity  Anorexia, nausea, vomiting, diarrhea  Visual disturbances (blurred vision, seeing green or yellow halos around objects)

38. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications (cont’d)  Check dosage forms carefully, and follow instructions for giving  Avoid giving digoxin with high-fiber foods (fiber binds with digitalis)  Patients should report immediately a weight gain of 2 or more pounds in 1 day or 5 or more pounds in 1 week

39. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications (cont’d)  Inamrinone or Milrinone  Use an infusion pump  Monitor I&O, heart rate, BP, daily weights, respirations, etc.  IV Inamrinone  Do not mix with dextrose  Solution color is true yellow

40. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Positive Inotropic Drugs: Nursing Implications (cont’d)  Monitor for therapeutic effects  Increased urinary output  Decreased edema, shortness of breath, dyspnea, crackles, fatigue  Resolving of paroxysmal nocturnal dyspnea  Improved peripheral pulses, skin color, temperature  Monitor for adverse effects

41. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Question  When teaching the patient the signs and symptoms of cardiac glycoside toxicity, the nurse should alert the patient to watch for;  A. Visual changes such as photophobia  B. Flickering lights or halos around lights  C. dizziness when standing up  D. Increased urine output

42. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Question  During assessment of a patient receiving Digoxin, which finding would indicate an increased possibility of toxicity?  A. Apical rate of 62  B. Digoxin level of 1.5 ng/ml  C. Serum potassium level of 2 mEq/L  D. Serum potassium level of 4.8 mEq/L

43. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Question  When monitoring a patient who is receiving an IV infusion of Inocor, the nurse will look for which adverse effect?  A. Thrombocytopenia  B. Proteinuria  C. Anemia  D. Decreased BUN/Creatinine levels

44. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Question  When administering the daily dose of digoxin 0.125mg PO to a patient with IDDM who is now in heart failure, it is most important for the nurse to:  A. Give medication with a class of orange juice.  B. Monitor the patient for dysrhythmias.  C. Administer it 1 hour before the morning dose of insulin.  D. Withhold dose if the apical heart rate is less then 80 beats per minute.

45. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Case Scenario Heart Failure  Mrs. Allen is a 76 year old female admitted with heart failure. She has been started on Digoxin 0.125 mg po. Your initial assessment of this patient revealed the following:  AAOx1  Vitals: P 110, RR 33, BP 110/56 SAO2 92%  +2 pedal edema  Bilateral basilar crackles, SOB on minimal exertion

46. Mosby items and derived items © 2007, 2005, 2002 by Mosby, Inc., an affiliate of Elsevier Inc. Scenario con’t  Weight gain of 2 lbs over past 5 days  Urine output =240 ml/8 hr shift