A nurse is caring for a client who has heart failure and has been taking digoxin 0.25 mg daily. The client refuses breakfast and reports nausea. Which of the following actions should the nurse take first?

A. Request a dietary consult: Helpful for ongoing nutrition issues but not the immediate first action when nausea may signal digoxin intolerance or toxicity. B. Request an order for an antiemetic: May be appropriate after assessment, but not the first step. Determine cause of nausea first. C. Check the client's vital signs: Nausea in a client on digoxin can indicate toxicity; check vital signs (especially heart rate and rhythm) before administering that day’s dose. If bradycardia or arrhythmia is present, withhold digoxin and notify the provider. D. Suggest that the client rests before eating the meal: May be comforting advice but does not address potential medication toxicity or the immediate need to assess for bradycardia/arrhythmia.