Digoxin

Question 1

Class

Answer 1

Cardiac stimulant

Question 2

Actions

Answer 2

Slows heart
Slows AV conduction
Prolongs AV node
refractory period
Increases force of
contraction in failing
heart

Question 3

Mechanism of action

Answer 3

Inhibits Na+/K+ ATPase in
plasma membrane
Increased intracellular Na+
reduces Ca2+ extrusion
thus increasing Ca2+

Question 4

Clinical use

Answer 4

Atrial fibrillation

Heart failure

Question 5

Adverse effects

Answer 5

Dysrhythmias
Yellow vision
Nausea
Vomiting

Question 6

what is Digoxin

Answer 6

A cardiac glycoside (A Sodium potassium ATPase inhibitor)

Question 7

what is digoxin used to treat

Answer 7

used to treat congestive heart failure, and supraventricular arrhythmias

Question 8

mode of action of Digoxin

Answer 8

via inhibition of the Na-K-ATPase membrane pump, resulting in an increase in intracellular sodium. This causes in turn the sodium calcium exchanger (NCX) to extrude the sodium and pump in more calcium.

Question 9

what happens as a result of the alteration in calcium concentration?

Answer 9

is thought to promote activation of contractile proteins (e.g., actin, myosin).

Question 10

other than the meberance pumpl, wha else does digoxin act on

Answer 10

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.

Question 11

current usage?

Answer 11

Still used in Atrial Fibrillation, but now very much third line treatment option

Question 12

is digoxin still used in heart failure

Answer 12

no because better drugs aavailabe