Question

A $55$-year-old male establishes care for hypertension management. His medical history is significant for bipolar I disorder and mild persistent asthma. His bipolar disorder has been well-controlled on lithium carbonate for the past eight years without recurrent mood episodes. His asthma is managed with an as-needed albuterol inhaler. Blood pressure readings from his past three clinic visits have consistently averaged $154/96$ mmHg, despite strict adherence to a low-sodium diet and a daily exercise regimen. Today, his blood pressure is $156/94$ mmHg, and his pulse is $72$/min. Physical examination reveals clear lungs bilaterally with no wheezing. Laboratory studies show a serum creatinine of $0.9$ mg/dL, serum potassium of $4.2$ mEq/L, and a serum lithium level of $0.8$ mEq/L (therapeutic range: $0.6$ to $1.2$ mEq/L). The physician decides to initiate pharmacologic therapy for his hypertension. Which of the following is the most appropriate medication to prescribe for this patient?