Most insurance company formularies list specific angiotensin receptor blockers (ARBs) and ACE inhibitors that they have approved for the treatment of diabetic nephropathy (proteinuria). Is the class effect of these agents sufficient? Or should we fight for specific medications?
—Absar Qureshi, MD, Columbus, Ohio
Since the introduction of ARBs, the question that has pervaded each clinician’s mind is whether or not these drugs serve an advantage in conditions long addressed by ACE inhibitors. Matchar et al demonstrated that the two drug classes are equally safe and effective in BP control and that they have similar effects on other risk factors and clinical outcomes in those with essential hypertension (Ann Intern Med. 2008;148:16-29). While these authors noted that ARBs are less likely to cause dry cough, they also suggested that perhaps the incidence of dry cough with ACE inhibitors is much less than previously indicated by randomized trials. On the other hand, Kunz et al demonstrated that monotherapy with either an ACE inhibitor or an ARB was similarly effective in reducing proteinuria, but combining the two classes works even better for this indication (Ann Intern Med. 2008; 148:30-48). These “class effect” mechanisms are similar among agents that effectively block the renin-angiotensin-aldosterone axis, as they pertain to “reduction of proteinuria.” It is believed that ACE inhibitors and ARBs slow chronic kidney disease progression by class effect mechanisms (e.g., reduction in glomerular capillary pressure, reduction in permselectivity, alterations in mesangial cell functioning, and interference with the angiotensin-mediated generation of free radicals) in addition to their antihypertensive and antiproteinuric effects.—Edgar V. Lerma, MD, clinical associate professor of medicine, Section of Nephrology, Department of Medicine, University of Illinois at Chicago College of Medicine/Associates in Nephrology(130-6)