A client is in the critical care unit. She is currently rece…

A client is in the critical care unit. She is currently receiving oxygen at 2 L/min by nasal cannula; nitroglycerin paste 1 inch to the chest wall, and  Metaprolol 25 mg orally every 12 hours. The monitor shows that the client has started having PVCs. Over the course of the next several hours, the premature ventricular contractions (PVC)  increase in frequency to more than 15 per minute, with occasional burst of multifocal bigeminal PVCs. The client’s vital signs are heart rate, 84 beats/min, sinus rhythm, with described PVCs; blood pressure, 124/68 mm Hg; respirations, 20 breaths/min; SpO2, 90%. Laboratory values are blood pH, 7.44; potassium, 4.6 mEq/L; and magnesium 0.9 mEq/L. Which of the following, if ordered, would be inappropriate for this client?