In the case of a client with hypertension and a prescription for lisinopril, which side effect requires immediate reporting?

Lisinopril, an ACE inhibitor commonly used to treat hypertension, can lead to a significant side effect that involves elevated potassium levels, known as hyperkalemia. This condition can be especially dangerous because it affects the heart's rhythm and function. When potassium levels rise too high, it can lead to serious cardiovascular complications, such as arrhythmias, which can be life-threatening.

Patients taking lisinopril must be monitored for potassium levels, and any significant increase requires immediate medical attention. While a dry cough, rash, and fatigue are potential side effects associated with lisinopril, they do not pose the same level of acute risk or require immediate intervention as hyperkalemia does. Therefore, recognizing elevated potassium levels as an urgent issue reflects an understanding of the possible severe complications that can arise from this medication.