Cardiovascular drugs can cause a variety of acid-base and electrolyte abnormalities that need to be considered when clinicians manage the large number of patients who receive these agents. Diuretic-induced metabolic alkalosis is the most common acid-base disorder observed and is associated with hypokalemia. Drug-induced hyperkalemia is the most important cause of increased potassium levels in everyday clinical practice. Multifactorial-origin diuretic-induced hyponatremia is mostly due to thiazides and should be carefully managed. This review focuses on the pathogenetic mechanisms as well as on the treatment of these metabolic derangements that are commonly encountered in patients who receive cardiovascular drugs.