A patient is on a low-dose dobutamine drip for heart failure. She had been feeling better but now has a sense of tightness in her chest, palpitations, and a bit of anxiety. Her heart rate is up to 110/min, and BP is 150/98 (increased from previous readings of 86/min and 120/80). What is the nurse's immediate concern for this patient?
A. She is experiencing normal therapeutic effects of dobutamine therapy.
B. She may be experiencing an allergic reaction to the dobutamine.
C. The medication may be causing a worsening of a preexisting cardiac disorder.
D. The dosage of the dobutamine needs to be increased to control the symptoms better.