The Difficult-to-Control Hypertensive Diabetic
A 57-year-old man with a 10-year history of type 2 diabetes mellitus visits the physician's office because his home blood pressures have been in the 140-145/85-90 mm Hg range for the last month. He takes four subcutaneous injections of various insulins, along with aspirin, ramipril, metoprolol succinate, simvastatin and clopidogrel since discharge from the hospital for acute coronary syndrome 3 months ago, which resulted in coronary angioplasty and two new bare metal stents. His office blood pressure is 146/86 mm Hg, but his physical examination is otherwise unremarkable. His electrolytes and blood glucose are unremarkable except for a BUN of 30 mg/dL and serum creatinine of 1.6 mg/dL (eGFR = 48 mL/min/1.73 m2); his A1C is 6.9%. Urinalysis is unremarkable by dipstick and microscopy, but his first urine specimen this morning had an albumin/creatinine ratio of 960 mg/gm.
WARNING: The United States Food and Drug Administration has not specifically approved many antihypertensive agents or drug combinations for reducing cardiovascular or renal risk; the discussion of drug choices in the context of this patient therefore may be interpreted as "off-label" uses of such drugs.
The most appropriate addition to his antihypertensive drug regimen is which of the following?