Which is the most appropriate action for the nurse to take before administering digoxin?
A. Monitor potassium level.
B. Assess blood pressure.
C. Evaluate urinary output.
D. Avoid giving with thiazide diuretic.
Correct Answer: A. Monitor potassium level.
Monitoring potassium is especially important because hypokalemia potentiates digoxin toxicity. Digoxin exhibits its therapeutic and toxic effects by poisoning the sodium-potassium ATPase. The subsequent increase in intracellular sodium leads to increased intracellular calcium by decreasing calcium expulsion through the sodium-calcium, cation exchanger. Blood pressure and urinary output are incorrect because these data reflect overall CV status but are not specific for digoxin.
Option B: Higher intracellular calcium increases inotropy which can be of symptomatic benefit in CHF. At toxic levels, automaticity can be increased as well. Digoxin also increases vagal tone by decreasing dromotropy at the AV node. This can be used to control atrial tachydysrhythmias.
Option C: Gastrointestinal upset is the most common symptom of digoxin toxicity. Patients also may report visual symptoms, which classically present as a yellow-green discoloration, and cardiovascular symptoms, such as palpitations, dyspnea, and syncope. Elderly patients frequently will present with vague symptoms, such as dizziness and fatigue. The most important historical detail in evaluating a random digoxin level is the time of the last dose.
Option D: Thiazide diuretics are usually administered with digoxin. Among patients taking digoxin (Lanoxin), low levels of potassium caused by concurrent digoxin and diuretics (thiazide & loop diuretics) may cause weakness, cramps, and irregular heartbeats.