The nurse is reviewing the laboratory result of a client receiving digoxin (Lanoxin) and notes that the result is 2.5 ng/mL. The nurse plans to do which of the following?
A. Give the next dose.
B. Notify the physician.
C. Check the client’s pulse rate.
D. Increase the next dose as ordered.
Correct Answer: B. Notify the physician.
The normal value therapeutic range for digoxin is 0.5 to 2 ng/mL. A level of 2.5 ng/mL indicates toxicity. The nurse should immediately inform the physician, who may give further instructions about holding the next doses of digoxin. Digoxin toxicity can present acutely after an overdose or chronically, as is often seen in patients on digoxin that develop acute kidney injury. Approximately 1% of CHF patients treated with digoxin develop toxicity. Additionally, 1% of adverse drug effects in patients greater than age 40 are due to digoxin toxicity; the incidence rises to greater than 3% in patients over age 85.
Option A: Clinical staff should monitor the plasma digoxin level at least 6 hours or 12 hours post-administration of the last loading dose as this is the time to achieve steady-state levels. Recommended thresholds of therapeutic serum digoxin levels are between 0.5 to 2 ng/dl.
Option C: The physician must request regular electrocardiograms and bloodwork to assess for renal function, and electrolytes require close monitoring. No more than 2 ml of the drug should be injected at the same site. The injection should be made deep into the muscle, and the overlying area massaged post-injection. Intravenous injections are metabolized more efficiently than intramuscular injections and are the preferred route, as only about 80% of the drug is absorbed in intramuscular injections as compared to intravenous dosing.
Option D: Digoxin has a narrow therapeutic index. The recommended serum levels stand between 0.8 to 2 ng/mL. When measuring a digoxin serum level, it is essential to draw blood at least 6 to 8 hours after the last dose. The toxicity increases as the serum drug levels increase above 2.0 ng/mL.