Multiple Choice: Therapeutic drug monitoring

Question 1.

An 87-year-old woman has been taking digoxin for atrial fibrillation for 15 years, but now complains of nausea and reduced mobility. Her current dose of digoxin is 187.5 micrograms orally daily. Her digoxin level is 3.0 nmol/L (therapeutic range 1.0-2.6 nmol/L).

Which of the following is the most appropriate course of action?