Estimation of glomerular filtration rate to prevent life-threatening hyperkalemia due to combined therapy with spironolactone and angiotensin-converting enzyme inhibition or angiotensin receptor blockade

Since publication of the Randomized Aldactone Evaluation Study (RALES), it has become a common practice to add spironolactone to angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers for the treatment of moderate to severe congestive heart failure (CHF).(1) Unfortunately, reports of an increased incidence of hyperkalemia associated with this treatment have started to emerge.(2,3).