Losartan as an alternative to ACE inhibitors in patients with renal dysfunction.

Abstract

Losartan-induced acute renal failure may occur in patients sensitive to reduced renal plasma flow. Such patients include those with bilateral renal artery stenosis, severe congestive heart failure, and severe sodium and volume depletion because their renal function is often angiotensin-dependent. Theoretically, both ACE inhibitors and losartan could adversely affect renal function in such sensitive patients. The ELITE trial showed a 10.5% incidence of losartan-induced renal dysfunction in elderly patients with congestive heart failure with no known underlying renal dysfunction, an incidence identical to that for captopril. A review of the literature revealed no controlled trials that specifically address whether losartan can be used as an alternative in patients in whom renal dysfunction associated with losartan have been published and an additional case report was identified from a local adverse drug reaction monitoring program. There were two cases of patients who developed renal dysfunction while receiving ACE inhibitors and then losartan. We found only one published case in which losartan was used without deterioration in renal function in patients who developed renal dysfunction while taking an ACE inhibitor, although underreporting of such cases would be expected. There was one case of renal dysfunction with losartan after a lack of renal dysfunction while the patient was taking an ACE inhibitor. The remaining three reports are of patients who developed renal dysfunction while taking losartan with no antecedent ACE inhibitor use. All case reports describe renal deterioration that was reversible upon discontinuation of the inciting agent, whether an ACE inhibitor or losartan. All but two patients (personal communication, Barbara Cadario) had underlying renal pathology. Although there is a paucity of published literature and the clinical experience of some may suggest otherwise, there is currently no evidence (with the exception of 1 case report) to suggest that losartan is any better tolerated than ACE inhibitors from the standpoint of renal toxicity. Available evidence suggests that this is equally true in patients with and without underlying renal dysfunction. Furthermore, case reports suggest that, as with ACE inhibitors, losartan should be avoided in patients with bilateral renal artery stenosis and in patients with unilateral renal artery stenosis in a solitary kidney. In patients with underlying renal dysfunction, regardless of whether they tolerate ACE inhibitors, losartan may be used if deemed necessary. Renal function should be monitored and losartan should be stopped if evidence of renal dysfunction becomes apparent, since several case reports and a randomized trial suggest that losartan may cause the same negative renal effects as ACE inhibitors.