Introduction to Clinical Pharmacology Chapter 38- Cardiotonics and Inotropic Drugs

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Introduction to Clinical Pharmacology

Chapter 38-Cardiotonics and Inotropic Drugs

Introduction to Clinical Pharmacology

Chapter 38-Cardiotonics and Inotropic Drugs


Heart FailureHeart Failure

• Most common symptoms associated with HF include:

– Left ventricular dysfunction

– Shortness of breath with exercise

– dry hacking cough or wheezing

– orthopnea, restlessness, edema

• Left ventricular dysfunction

– Pulmonary symptoms-dyspnea, moist cough with production of frothy, pink sputum

– EF less than 40%, heart is enlarged and dilated

• Right ventricular dysfunction

– Peripheral edema, wt. gain


Cardiotonics: Actions and UsesCardiotonics: Actions and Uses• Actions:

– Increase cardiac output through positive inotropic activity; they slow the conduction velocity through the atrioventricular (AV) node in the heart and decrease the heart rate through a negative chronotropic effect

• Uses:

– Used to treat: Heart failure; atrial fibrillation

– Patients with persistent symptoms, recurrent hospitalizations, or as indicated in conjunction with ACE inhibitors, loop diuretics and B blockers


Cardiotonics: Adverse ReactionsCardiotonics: Adverse Reactions

• Central nervous system reaction:

– Headache; weakness; drowsiness; visual disturbance

• Cardiovascular and gastrointestinal reactions:

– Arrhythmias; gastrointestinal upset; anorexia


Cardiotonics: Contraindications and PrecautionsCardiotonics: Contraindications and Precautions

• Contraindicated: In the presence of digitalis toxicity and in patients with known hypersensitivity, ventricular failure, ventricular tachycardia, cardiac tamponade or AV block

• Precautions: Patients with electrolyte imbalance, severe carditis, heart block, myocardial infarction, severe pulmonary disease, acute glomerulonephritis, impaired renal or hepatic function

– Digoxin and digoxin immune fab used cautiously during pregnancy and lactation, when the potential benefit outweighs the potential harm to the fetus

changed "patient" to "client"added ","


Cardiotonics: InteractionsCardiotonics: InteractionsInteractant drug Effect of interactionAmiodarone Increased plasma

digitalis levels leading to toxicity

BenzodiazepinesIndomethacin Itraconazole Macrolides Propafenone Quinidine Spironolactone Tetracyclines Verapamil


Miscellaneous Inotropic DrugsMiscellaneous Inotropic Drugs

• Inamrinone and milrinone: have inotropic actions and are used in the short-term management of severe HF that is not controlled by the digitalis preparations

• Nurse must continuously monitor the patient’s heart rate and blood pressure with administration of either drug

• If hypotension occurs, the drug is discontinued or the rate of administration is reduced

• Continuous cardiac monitoring is necessary because life-threatening arrhythmias may occur

changed "patient" to "client"


Nursing Process: AssessmentNursing Process: Assessment

• Preadministration assessment:

– The physical assessment should include:

• Taking blood pressure, apical-radial pulse rate, respiratory rate

• Auscultating the lungs, noting any unusual sounds during inspiration and expiration

• Examining the extremities for edema

• Checking the jugular veins for distention

• Measuring weight


Nursing Process: AssessmentNursing Process: Assessment• Preadministration assessment: (cont’d)

• Inspecting sputum raised (if any), and noting the appearance (e.g., frothy, pink-tinged, clear, yellow)

• Looking for evidence of other problems, such as cyanosis, shortness of breath on exertion (if the patient is allowed out of bed) or when lying flat, and mental changes

– The primary care provider also may order laboratory and diagnostic tests

change "patient" to "client"



• Preadministration assessment: (cont’d)

– Because digoxin reacts with many medications, the nurse must take a careful drug history

– Before administering each dose of a cardiotonic, the nurse takes the apical pulse rate for 60 seconds, records it in the designated area on the chart or the medication administration record

– Pulse rate below 60bpm and above 100bpm in adults: withhold the drug and inform the primary health care provider, PEDS-notify PCP if AP <70 bpm or below 90 bpm in infant




• Ongoing assessment: (con’td)

– Weighs patients receiving a cardiotonic drug daily, or as ordered

– I and O, especially in the presence of edema or HF

– Assess the patient for peripheral edema and auscultates the lungs for rales or crackles throughout therapy



Nursing Process: PlanningNursing Process: Planning

• The expected outcomes of the patient depend on the specific reason for administering the drug, but may include:

– Optimal response to therapy

– Support of patient needs related to the management of adverse reactions

– Understanding of and compliance with the prescribed drug regimen



Nursing Process: ImplementationNursing Process: Implementation• Promoting an optimal response to therapy

– The nurse should carefully check the primary care provider’s order and the drug container

– Digitalization

•Maybe accomplished by two general methods: Rapid digitalization and gradual digitalization

•Involves giving a series of doses until the drug begins to exert a full therapeutic effect, additional freactions of the digitalis dose are administered at 6-8 hour intervals


Nursing Process: ImplementationNursing Process: Implementation• Promoting an optimal response to therapy (cont’d)

– Digitalization (cont’d)

• During digitalization, the nurse takes the blood pressure, pulse, and respiratory rate every 2 to 4 hours or as ordered by the primary care provider

• Periodic electrocardiograms, serum electrolytes, hepatic and renal function tests, and other laboratory studies also may be ordered


Nursing AlertNursing Alert

• Plasma digoxin levels are monitored closely

• Plasma levels should be drawn immediately before the next dose or 6-8 hours after the last dose regardless of route

• Plasma dig. Levels greater than 2 nanograms/ml are toxic are must be reported to PCP

• Hypokalemia makes heart muscle more sensitive to digitalis, increasing the possibility of developing digitalis toxicity


Nursing Process: ImplementationNursing Process: Implementation• Promoting an optimal response to therapy

(cont’d)

– Parenteral administration:

•The nurse may give a cardiotonic orally, IV, or intramuscularly (IM)

•When a cardiotonic drug is given IV, it is administered slowly and the administration site is assessed for redness or infiltration

•When giving a cardiotonic drug IM, the nurse should rotate the injection sites


Nursing Process: ImplementationNursing Process: Implementation

• Promoting an optimal response to therapy (cont’d)

– Oral Administration:

• Nurse can administer oral preparations without regard to meals

• Monitoring and managing patient needs

– Risk of imbalanced nutrition: Less than body requires

• Observe the patient for adverse reactions, such as anorexia, vomiting, nausea (symptoms of toxicity)

changed "patient" to "client"and "weight" to "requires"


Nursing Process: ImplementationNursing Process: Implementation• Monitoring and managing patient needs (con’td)

– Potential complication: Digital toxicity

• Observe for signs of digitalis toxicity- 2-4 hours during digitalization and 1-2 times a day

• Digoxin toxicity can be successfully treated by simply withdrawing the drug; severe life-threatening toxicity is treated with digoxin immune fab

• Nurse should be alert for the possibility of worsening HF, low cardiac output, hypokalemia, or atrial fibrillation

• Give atropine if bradycardia develops!!

change "patient" to "client"Other changes in red


Nursing Process: ImplementationNursing Process: Implementation

• Educating the patient and family:

– If HR falls below 60 bpm in adult, 70 bpm in child-instruct them to call PCP

– The patient and family must understand that the prescribed drug must be taken exactly as directed by the primary care provider-do not miss or double a dose

– Show the patient or a family member the correct technique for taking the pulse



Nursing Process: EvaluationNursing Process: Evaluation

• The therapeutic effect is achieved

• The patient maintains an adequate nutritional status

• The patient is able to carry out activities of daily living

• Adverse reactions are identified, reported to the primary care provider, and managed using appropriate nursing interventions

• The patient verbalizes the importance of continued follow-up care



Nursing Process: Evaluation (cont’d)Nursing Process: Evaluation (cont’d)

• The patient verbalizes the importance of complying with the prescribed therapeutic regimen

• The patient and family demonstrate an understanding of the drug regimen

• The patient complies with the prescribed drug regimen


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Introduction to Clinical Pharmacology Chapter 38- Cardiotonics and Inotropic Drugs

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