Hyperkalemia is defined as serum potassium concentrations elevated above the upper limit of normal (> 5.0 mEq/L). It has become more common in cardiovascular practice due to the growing population of patients with chronic kidney disease and the broad application of drugs that modulate renal elimination of potassium by reducing production of angiotensin II (angiotensin-converting enzyme inhibitors, direct renin inhibitors, β-adrenergic receptor antagonists), blocking angiotensin II receptors (angiotensin receptor blockers), or antagonizing the action of aldosterone on mineralocorticoid receptors (mineralocorticoid receptor antagonists). The risk of hyperkalemia is a major limiting factor for the use of these disease-modifying drugs in both acute and chronic cardiorenal syndromes. Thus, agents to control the plasma concentration of potassium are needed in the multidrug treatment of cardiorenal disease, including chronic kidney disease, heart failure, and acute kidney injury. Novel oral therapies in development for both acute and extended use in the management of hyperkalemia include patiromer sorbitex calcium and sodium zirconium cyclosilicate. Important biochemical differences between these compounds result in unique product profiles and electrolyte outcomes in patients treated for hyperkalemia. This review highlights the major mechanisms of hyperkalemia and key results from randomized trials in a range of clinical scenarios in patients with, and at risk for, hyperkalemia.