心衰竭病人主要是由於心臟充滿血液卻無力打出，或者是由於心臟無法打出足夠血量供身體使用。紐約心臟協會將心衰竭分成四級。心衰竭在現今標準藥物療法有angiotensin-converting enzyme inhibitor, digoxin, diuretics和β-blocker。在利尿劑方面，心衰竭病人主要使用有保鉀型、loop、thiazide類利尿劑。Thiazide類由於會降低血中鉀離子濃度，所以此類藥物會與保鉀型利尿劑合併使用，來減少此現象。而加入保鉀型利尿劑中的spironolactone更可減少心衰竭病人住院率及死亡率。由此可知利尿劑的使用對心衰竭病人有其重要之價值。
 

Heart failure is a disease that results from the inability of the heart to fill with or eject blood with the needs of body. New York Heart Association describes the congestive heart failure into four classes. In view of diuretic agents, physicans always prescribe potassium-sparing, loop, and/or thiazide diuretics. For thiazide diuretics would decrease the serum potassium level, clinicians always prescribe combination of potassium-sparing and thiazide diuretics. Administration of potassium-sparing diuretics (e.g. spironolactone) also reveals significant benefits on morbidity and mortality. Thus, diuretic agents play an important role in therapy for congestive heart failure.