A nurse is reviewing the vital signs of a client who has a prescription for imipramine. Which of the following findings requires follow-up by the nurse?

A. Temperature 36.7° C (98° F): This temperature is within normal limits for an adult and does not indicate a complication related to imipramine use. No immediate intervention is needed based on this finding. B. Respiratory rate 16/min: A respiratory rate of 16 breaths per minute is within the normal adult range (12–20/min) and does not raise concern for adverse effects from imipramine. It requires routine monitoring only. C. Blood pressure 88/64 mm Hg: Imipramine, a tricyclic antidepressant, can cause orthostatic hypotension and other hypotensive effects. A blood pressure of 88/64 mm Hg is lower than normal and may indicate drug-induced hypotension, which requires follow-up, monitoring for symptoms such as dizziness or syncope, and possibly notifying the prescriber. D. Pulse rate 66/min: A pulse rate of 66 beats per minute is within the normal adult range (60–100 bpm) and does not indicate a cardiovascular complication related to imipramine. Routine monitoring is sufficient.