Madhav V. Rao, MD1, Department of Medicine, Section of Nephrology, University of Chicago, Chicago, IL, USA.
Vijaykumar M. Rao, MD, FACP, FASN, President, Associates in Nephrology, Chicago, IL, USA.

Alterations in potassium balance occur frequently in all patient populations, but in particular, among older adults. Physicians commonly encounter such disorders when taking care of patients in the clinic or in the hospital. Most often the etiology of such disturbances is due to prescribed medications, but a number of clinical conditions exist which predispose people to both hyperkalemia and hypokalemia. These conditions can have grave consequences if not addressed quickly. Furthermore, the approach to definitive treatment depends on the underlying physiology that often occurs at the tubular level within the kidney.
Key words: potassium balance, hyperkalemia, hypokalemia, older adults.

Robert E. Hobbs, MD, The Kaufman Center for Heart Failure, Department of
Cardiology, Cleveland Clinic Foundation, Cleveland, OH, USA.

Guidelines for managing heart failure recommend angiotension-converting enzyme (ACE) inhibitors, beta-blockers, diuretics, digoxin, and aldosterone antagonists as standard therapy in order to improve morbidity and mortality. Angiotensin receptor blockers (ARBs) are considered second-line agents for patients who are intolerant of ACE inhibitors due to cough or angioedema. Because ACE inhibitors do not completely block the formation of angiotensin II and aldosterone, add-on therapy with an ARB has been evaluated in several clinical trials. In general, the results were mixed. Combination therapy with an ACE inhibitor and an ARB may improve morbidity and probably mortality, but with an increased incidence of hypotension, hyperkalemia, and azotemia. This approach could be considered in patients who remain symptomatic despite optimal doses of standard agents.

Key words: angiotensin receptor blockers, ACE inhibitors, heart failure, vasodilators, hyperkalemia.