The correct answer is:

Angiotensin-converting enzyme (ACE) inhibitor

Educational Objective:

Describe the effects of ACE inhibitors and ARBs on renal function in patients with chronic kidney disease and proteinuria.

Key Points:

In chronic kidney disease with proteinuria, either ACE inhibitors or angiotensin receptor blockers (ARBs) reduce urinary protein and slow the progression of renal failure.

Explanation:

Hypertension is present in approximately 80 to 85 percent of patients with CKD and is thought to be multi-factorial (sodium retention, increased activity of the renin-angiotensin system, and enhanced activity of the sympathetic nervous system).

In patients with proteinuric (defined as protein excretion above 500 to 1000 mg/day) CKD, first-line therapy consists of an ACE inhibitor or angiotensin receptor blocker as first-line therapy for the treatment of hypertension (Grade 1A).

ACE inhibitors, in addition to reducing intra-glomerular pressure, reduce the excretion of urinary protein (both of which delay the progression of renal failure). Angiotensin receptor blockers (ARBs) have a similar effect. Aside from blood pressure control, the aim is to reach less than 1000 mg/day of protein spilling into the urine.

In patients with edema, a thiazide diuretic can be added as a second-line drug; chlorthalidone is preferred over hydrochlorothiazide because of its longer duration of action. A dihydropyridine calcium channel blocker is appropriate as a second-line drug for patients without fluid retention. Neither a beta-blocker nor a sympathetic, such as aldactone, demonstrate the protective effect of ACE inhibitors or ARBs.

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