Question

1. All of the following statements regarding cardiac glycosides are true EXCEPT:
A. They inhibit the Na+/K+-ATPase and thereby increase intracellular Ca++ in myocardial cells.
B. They cause a decrease in vagal tone.
C. Children tolerate higher doses of digitalis than do adults.
D. The most frequent cause of digitalis intoxication is concurrent administration of diuretics that deplete K+.
E. A and C

Answer 1

Answer:

They inhibit the Na+/K+-ATPase and thereby increase intracellular Ca++ in myocardial cells

b) They cause a decrease in vagal tone

c) Children tolerate higher doses of digitalis than do adults

d) The most frequent cause of digitalis intoxication is concurrent administration of diuretics that deplete K+

Answer 2

Answer:

The incorrect option is B. They cause a decrease in vagal tone.

Explanation:

Statement A. They inhibit the Na+/K+-ATPase and thereby increase intracellular Ca++ in myocardial cells. is correct.

Statement B. They cause a decrease in vagal tone. The statement is incorrect as it decreases the sympathetic nerve activity and thus increases the cardiac vagal tone.

Statement C. Children tolerate higher doses of digitalis than do adults. The statement is correct as tissue uptake of cardiac glycosides in children is much higher than the adults.

statement D. The most frequent cause of digitalis intoxication is concurrent administration of diuretics that deplete K+. The statement is correct.