Question

1)A 75-year-old female in congestive heart failure (CHF) is unable to climb a flight of stairs without experiencing shortness of breath. Digoxin is administered to improve cardiac muscle contractility. Within two weeks, she has a marked improvement in her symptoms. What cellular action of digoxin accounts for this?
a) Inhibition of cAMP synthesis
b) Inhibition of Ca- release
c) Inhibition of the Na+/K+ ATPase pump​
d) Inhibition of β adrenergic stimulation
e) Inhibition of ATP degradation

2) A 65-year-old female receives digoxin and furosemide for CHF. After several months, she develops nausea and vomiting. Serum K4 is 2.5 mEq/L. Electrocardiogram (EKG) reveals an AV conduction defect. What cellular effect is causing these new findings?
a. Increased intracellular K+
b. increased intracellular cGMP
c. Increased intracellular Ca2+​
d. Increased intracellular norepinephrine
e. Increased intracellular nitric oxide (NO)

3)A 59-year-old female with mild CHF is treated with furosemide. What is its primary mechanism of action?
a. Inhibition of Na+,1c ATPase​
b. Inhibition of Nat, K+, CF co-transporter
c. Inhibition of Na+,C1 co-transporter​
d. Inhibition of Cl— transporter
e. Inhibition of Ca2+ transporter

4)Compensatory increases in heart rate and renin release that occur in heart failure may be alleviated by which of the following drugs?
a. Milrinone
b. Digoxin
c. Dobutamine
d. Enalapril
e. Metoprolol

5 )A 58-year-old man is admitted to the hospital with acute heart failure and pulmonary edema. Which one of the following drugs would be most useful in treating the pulmonary edema?
a. Digoxin
b. Dobutamine
c. Furosemide
d. Minoxidil
e. Spironolactone

Answer 1

ANSWER 1:- Option C is correct ( Inhibition of Na+/K+ ATPase pump).

EXPLANATION: Digoxin inhibits Na-K ATPase, which in turn causes increased availability of intracellular calcium in the myocardium and conduction system. As we know calcium in myocardium causes contraction of heart muscles so increased amount of calcium will increase contractility.

ANSWER 2:- Option C is correct ( Increased intracellular Ca2+).

EXPLANATION:- Electrolyte disturbances in a patient taking digoxin in long term cause hypomagnesemia, hypercalcemia, and hypokalemia (due to use of diuretic, Furosemide) that lead to increased sensitivity to digoxin making toxicity more likely even with a lower concentration of serum digoxin.

ANSWER 3:- Option b is correct (Inhibition of Nat, K+, CF co-transporter).

EXPLANATION: Furosemide is a  Loop diuretic. It inhibits reabsorption of sodium and chloride ions at proximal and distal renal tubules and loop of Henle; by interfering with chloride-binding cotransport system, and removes water and salt from body.