Cardiotonics

Question 1

CHF Forward Failure

Answer 1

• Systolic dysfunction; unable to pump blood forward resulting in reduced cardiac output (CO)

Question 2

CHF Backward Failure

Answer 2

• Diastolic dysfunction; ventricle is unable to relax to permit proper filling of blood resulting in cardiac/pulmonary congestion

Question 3

Pathophysiology Chart of CHF

Answer 3

Question 4

Classification and Treatment of Chronic Heart Failure Chart

Answer 4

Question 5

Inotropic Drugs

Answer 5

• Modifying the force or speed of contraction of muscles
• Digoxin
• Dobutamine
• Milrinone

Question 6

Digoxin MOA

Answer 6

• Inhibition of Na/K ATPase

*pos. inotropic effect

*neg. chronotropic effect: vagal stimulation

Question 7

Effects of Digoxin on Electrical Properties of Cardiac Tissues Chart

Answer 7

Question 8

Digoxin MOA Illustration

Answer 8

Question 9

Digoxin Pharmacokinetics

Answer 9

• Medium lipid solubility; good oral bioavailability (75%); t1/2: 40hrs; percentage metabolized: <40%

Question 10

Digoxin Clinical Uses

Answer 10

• Effective for pts. w/ systolic dysfunction

Question 11

Digoxin Adverse Effects/Toxicity

Answer 11

• Nausea, vomiting, anorexia, diarrhea
• Visual disturbances
• CNS- headache, confusion, hallucinations
• Electrolyte interaction

*hypokalemia

*hyperkalemia

*hypercalcemia

• Cardiac arrhythmias: AV block, PVC’s, ventricular tachycardia, ventricular fibrillation

Question 12

Treatment of Digoxin Toxicity

Answer 12

• K+ salts, antiarrhythmics, digoxin immune fab

Question 13

Digoxin Drug Interactions

Answer 13

• Diuretics, quinidine

Question 14

Dobutamine MOA

Answer 14

• Beta adrenergic drug
• Stimulates beta-1 adrenergic receptors and increases cardiac contractility; enhance intracellular calcium in myocytes

Question 15

Milrinone MOA

Answer 15

• Phosphodiesterase Inhibitor
• Inhibit degradation of cAMP resulting in increased myocardial contractility

Question 16

Stages of Heart Failure

Answer 16