CARDIAC GLYCOSIDES

Question 1

What are cardiac glycosides?

Answer 1

Cardiac glycosides are the most effective drug for the treatment of CHF, they are plant alkaloid,they increase myocardial contraction which will increase blood supply to all organs including the kidney therefore causing diuresis which will decrease the edema. They are also used to treat cardiac arrhythmia because they decrease heart rate.

Question 2

What is the mode of action of cardiac glycosides?

Answer 2

They increase the contractility of the heart muscle by minimizing the movement of sodium ion and potassium ion and increasing the release of calcium ion in the myocardial cells.
It decreases the heart rate due to the parasympathetic tone increase and sympathetic tone decrease.

Question 3

How are they excreted?

Answer 3

Primarily through the kidneys

Question 4

What are the therapeutic uses of cardiac glycosides?

Answer 4

1. Congestive heart failure

2. Cardiac arrhythmias

Question 5

What are the contraindications of cardiac glycosides

Answer 5

1. Hypersensitivity
2. Angina pectoris
3. Given with caution to elderly people and patients with kidney failure

Question 6

What are the side effects of cardiac glycosides?

Answer 6

• They are extremely toxic and may cause death.There is a narrow margin of safety between the therapeutic dose and the toxic dose.
• Could cause overdose by the accumulative effects of the drug,frequent assessment of the serum level is essential.
• Nausea
• Vomiting
• Diarrhea
• Skin rashes
• Blurring of vision

Question 7

What action is to be taken when a patient is suffering from digitalis intoxication?

Answer 7

Admit the patient into the icu for continuous monitoring of ECG and administration of digitalis drug should be halted.
If serum potassium is below normal,administered potassium salt and give anti-arrhythmic drug.

Question 8

What are the drug interactions of cardiac glycosides?

Answer 8

• Antacid decreases the therapeutic effects of digitalis.

- Furosemide increases potassium loss and increases the chances for digitalis toxicity.

Question 9

What are the predisposing factors to digitalis toxicity?

Answer 9

• Hypokalemia
• Pathological condition I.e liver disease which decreases metabolism therefore increases digitalis concentration ,kidney disease which decreases excretion of the drug thereby increasing the level of digitalis in the body.

Question 10

What are the nursing considerations for cardiac glycosides

Answer 10

1. Check doctors order,medication record and bottle labelled accurately.
2. Observe and monitor for evidence of bradycardia or arrhythmia.
3. Weigh the patient on a daily basis.
4. Always check their pulse rate.
5. Provide the patient with food high in potassium I.e banana and oranges.
6. Monitor serum level of digoxin.
7. In elderly patient try to access for early signs of toxicity.
8. Teach the patient that if the heart rate is below 60b/m to hold /stop the medication and see the doctor.
9. Have the digoxin antidote available.

Question 11

Give the pharmacology of two named cardiac glycosides.

Answer 11

1.DIGITOXIN
Trade name: Crystodigin
Class: Cardiac glycosides
Uses: Drug of choice for the maintenance in CHF
Doses: Digitalizing dose is 0.6mg every 4-6hrs while maintenance dose is 0.05-0.3mg per day.

2.DIGOXIN
Trade name: Lanoxin
Class: Cardiac glycosides
Uses: Drug of choice for CHF because; it has a rapid onset,it has a short duration and it came be administered orally or intravenously.
Doses: Digitalizing dose is 0.4-0.6mg 4hrly while the maintenance dose is 0.05-0.35mg once or twice daily.