CARDIAC GLYCOSIDES:
Digoxin (Lanoxin)
Action : Increases force of myocardial contraction (positive inotropic effect). Decreases rate of conduction (negative chronotropic effect) while increasing refractory period of the AV node. Positive inotropic effect improves blood supply to vital organs and kidneys, providing a diuretic effect. Has a slow onset and shorter duration of action than other cardiac glycosides. Is eliminated through the kidneys. Digoxin elixir is better absorbed by the GIT than digoxin tablets.
Use : CHF, atrial fibrillation; atrial flutter; paroxysmal atrial tachycardia.
A/E : With toxicity there are many symptoms that make it difficult to distinguish from the condition being treated. Arrhythmias, bradycardia: arrhythmias more frequently seen in children; anorexia,nausea, vomiting, diarrhea; headaches, fatigue, confusion, insomnia, convulsions; visual disturbances: blurred vision, green or yellow tint or halos; hypersensitivity. Toxicity occurs more quickly in presence of low serum potassium. Quinidine-digoxin reaction may occur. When digoxin is stabilized in clients receiving quinidine, serum digoxin levels could double, leading to possible toxicity.
Nsg. Implications:
a. Half-life is longer in elderly
b. Monitor CBC, serum electrolytes, liver and renal function tests, and ECG
c. Hold if apical rate is below 60 or greater than 120 beats per min. in adults, below 90/min in infants, or below 70/min in children up to adolescence.
d. Monitor I&O and daily weights; potassium levels. Encourage foods high in potassium.
e. Monitor digoxin levels therapeutic range (0.5-2.0ng/ml).
f. Give after meals if with GI distress.
g. Do not confuse digoxin with digitoxin (Crystodigin) as they are not the same.
h. IM injections are painful and absorption is erratic. Avoid IM injections if possible and give in large muscle mass.
i. Digoxin antidote: Digoxin Immune Fab (Digi-bind)
Discharge Teachings:
a. Take radial pulse and notify physician if toxicity symptoms occur.
b. Take dose the same time each day and do not skip or double up on dose.
c. Avoid high-sodium foods. Increase dietary intake of potassium.
d. Daily weights
e. Separate digoxin from other pills in pillbox.
*take the short quiz below...
1. What is most important for the nurse to teach a mother of a 2 month old child who is on digoxin?
a. Take apical pulse before giving digoxin
b. Take weight daily
c. Provide foods high in potassium
d. Monitor I&O
A - Children and infants are prone to arrhythmias, which are a toxic effect of digoxin. Teaching the mother to take an apical pulse will help to identify if there is a potential for arrhythmias.
2. Which of the following cardiac glycosides is preferred for clients who have renal failure?
a. Digoxin (lanoxin)
b. Digitoxin (Crystodigin)
c. Deslanoside (Cedilanid-D)
d. Amrinone (Inocor)
B - Digitoxin is eliminated and metabolized through the hepatic system and not the kidneys; is considered safer to use in clients with renal failure.
3. A mother asks the nurse which pulse rate indicates a dose of digoxin should be withheld for her 2 month old child. The nurse responds, "Hold the digoxin if the pulse rate is:
a. below 60beats/min
b. below 70beats/min
c. below 90beats/min
d. below 120 beats/min
C - Fewer than 90 beats/min in an infant is a sign of bradycardia, which could indicate digoxin toxicity.
4. The nurse would know that the mother understands teaching about A/E's of digoxin if she said:
a. "I'll call the physician if my child's pulse is below 120beats/min."
b. "If my child develops a rash I'll use A&D ointment."
c. "I will call the physician daily to report my child's weight and daily intake and output."
d. "I will notify the physician if my child vomits or develops diarrhea."
D - Vomiting and diarrhea are A/E's of digoxin therapy and may also be symptoms of digoxin toxicity; should be reported to physician for follow-up.
