This document discusses digitalis, a drug derived from foxglove plants that increases heart contraction and decreases heart rate. It focuses on digoxin and digitoxin, two cardiac glycosides used to treat heart conditions like congestive heart failure and arrhythmias. Digoxin is the preferred drug due to its longer half-life, while digitoxin is rarely used now. Both work by inhibiting sodium-potassium pumps, increasing intracellular calcium levels and strengthening heart muscle contractions. The document also covers digitalis toxicity treatment using digoxin immune fab antibody fragments.
2. CARDIAC GLYCOSIDE
Cardiac glycosides represent a family of compounds
that are derived from the foxglove plant (Digitalis
purpurea).
Cardiac glycosides are a class of organic compounds
that increase the output force of the heart and
decrease its rate of contractions by acting on the
cellular sodium-potassium ATPase pump.
3. ACTIONS
• On CVs: Digitalis increase oxygen
consumption of heart to normal. It increases
energy utilization, increases myocardial
contraction.
• Decreases venous return.
• Conduction system: Digitalis depresses the
conduction system by direct action.
4. DIGITALIS
• A drug prepared from the dried leaves of
foxgloves and containing substances (notably
digoxin and digitoxin) that stimulate the
heart muscle.
• The term digitalis is also used for drug
preparations that contain cardiac glycosides,
particularly one called digoxin, extracted from
various plants of this genus.
5. Digoxin and Digitoxin both drugs are cardiac
glycoside.
Digoxin ( Lanoxin) is usually the first choice drug,
because its half –life is 36 hours, whereas the
half-life of digitoxin is 4 to 9 days. Digitoxin is
rarely prescribed.
6. DIGOXIN
• Generic name: Digoxin.
• Brand name: Lanoxin, Lanoxicaps, Cardoxin,
Digitek.
• It is a cardiotonic glycoside obtained mainly from
Digitalis lanata.
• Digoxin has positive inotropic and negative
chronotropic activity.
• It is used to control ventricular rate in atrial
fibrillation and in the management of congestive
heart failure with atrial fibrillation.
7. • It is excreted via kidneys.
• Dosage: In Adults- oral solution 0.05mg/mL ,
Injectable solution- 0.1mg/mL.
8.
9. ACTION
• Digoxin inhibits the Na-K-ATPase membrane pump,
resulting in an increase in intracellular sodium.
• The sodium calcium exchanger (NCX)in turn tries to
extrude the sodium and in so doing, pumps in more
calcium
• . Increased intracellular concentrations of calcium may
promote activation of contractile proteins (e.g., actin,
myosin).
• Digoxin also acts on the electrical activity of the heart,
increasing the slope of phase 4 depolarization,
shortening the action potential duration, and
decreasing the maximal diastolic potential.
10.
11.
12. Indications: Heart failure, atrial fibrillation
Contraindications: Digitalis toxicity, ventricular
tachycardia/fibrillation, obstructive cardiomyopathy.
Side effects: Extra beats, anorexia, nausea and vomiting.
Diarrhoea in elderly, confusion, dizziness, drowsiness,
restlessness, nervousness, agitation and amnesia,
13. NURSING CONSIDERATION
Check dosage and preparation carefully.
Avoid IM injections, which may be very painful.
Follow diluting instructions carefully, and use diluted solution promptly.
Avoid giving with meals; this will delay absorption.
Have emergency equipment ready; have K+ salts, lidocaine, phenytoin,
atropine, and cardiac monitor readily available in case toxicity develops.
14. DIGITOXIN
It is a phytosteroid and is similar in structure and effects to
digoxin.
It is excreted via liver.
It could be used in patients with poor or erratic kidney
function.
It is now rarely used.
15. MECHANISM OF ACTION
Digitoxin inhibits the Na-K-ATPase membrane pump, resulting in an
increase in intracellular sodium and calcium concentrations.
Increased intracellular concentrations of calcium may promote
activation of contractile proteins (e.g., actin, myosin).
Digitoxin also acts on the electrical activity of the heart, increasing
the slope of phase 4 depolarization, shortening the action potential
duration, and decreasing the maximal diastolic potential.
16. • Indications: Congestive heart failure , atrial
flutter, atrial tachycardia, atrial fibrillation.
• Dosage: Adult and child age 12 years and
above , orally 1.2 to1.6 mg per day in divided
dose. Child 1 to 2 year age 0.04 mg per kg
weight.
• Contraindications: Hypersensitivity,
hypokalemia, pregnancy, lactation, hepatic
disease, A.V. block, ventricular tachycardia.
17. • Side effect: Hypersensitivity, hypokalaemia,
pregnancy, lactation, hepatic disease, A.V. block,
ventricular tachycardia.
• Nursing care:
1. To monitor drug level during therapy.
2. To monitor apical pulse rate, blood pressure during
therapy.
3. To carry out blood investigations, BUN, Creatinine,
ALT,AST, bilirubin.
4. To advice patient to take banana, orange juice in diet
as they are rich source of potassium.
18. DIGITALIS TOXICITY
Overdose or accumulation of digoxin causes digitalis
toxicity.
Signs and symptoms include anorexia, diarrhoea, nausea
and vomiting, bradycardia, premature ventricular
contractions, cardiac dysaarthmias, headache, malaise,
blurred vision, visual illusions, confusion.
19. TREATMENT OF DIGITALIS TOXICITY
• Digoxin immune fab or Digoxin-specific
antibody is an antidote for overdose of
digoxin.
• It works by binding to the digoxin, rendering
it unable to bind to its action sites on target
cells.
• It is made from immunoglobulin fragments
from sheep
20.
21. DIGOXIN IMMUNE FAB
• Action: Digoxin immune FAB do not allow
digoxin to bind to the sites of action and
reverse digoxin toxicity.
• Indications: Digoxin or digitoxin toxicity.
• Contraindications: Hypersensitivity, mild
digoxin toxicity, children , pregnancy, lactation.
• Side effects: Facial swelling, redness, rapid
respiration rate, low cardiac output.
22.
23.
24. NURSING CARE
To administer after diluting 40 mg in 4 ml water for
injection may further dilute with normal saline. Use clear
solution.
To evaluate therapeutic response , correction of digitoxin
toxicity .
To advice patient to report chills , fever, itching swelling,
dyspnea, urticaria to the treating doctor.