Renal risk with ACE inhibitor plus ARB
Combination therapy with an angiotensin-converting-enzyme (ACE) inhibitor and an angiotensin-receptor blocker (ARB) increases the risk of renal toxicity, a clinical practice trial confirms.
Finlay McAlister, from the University of Alberta in Canada, and colleagues reviewed the drug combination, compared with taking either drug alone, in 32,312 new users aged 65 years or older.
The 1750 patients taking both an ACE inhibitor and an ARB were more than twice as likely to have renal dysfunction as the patients receiving either drug as monotherapy, at 5.2 versus 2.4 events per 1000 patients per month.
They were also more likely to have hyperkalemia, at a respective 2.5 versus 0.9 events per 1000 patients per month.
The researchers also note in the CMAJ that 86% of patients prescribed the drug combination did not have either condition for which this therapy has been proven beneficial (proteinuria or symptomatic left ventricular systolic dysfunction) and that treatment was frequently stopped after only a few months, even when hyperkalemia or renal dysfunction did not occur.
"Although the absolute risks appear to be relatively low in our cohort of elderly patients, a 0.52% monthly risk of adverse renal outcomes is not insubstantial for a drug combination that would need to be taken for years to show any nephroprotective or cardioprotective effects," the team concludes.
"This is particularly relevant when you consider that most of the patients given this combination did not have conditions that have been proven to benefit from concomitant use of an ACE inhibitor and an ARB."
GP News is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Lucy Piper