diuretic diuretic a diuretic (/ˌdaɪjʊˈrɛtɪk/) is any substance that promotes diuresis, the increased production of urine. this includes forced diuresis. a diuretic tablet is sometimes colloquially called a water tablet. there are several categories of diuretics. all diuretics increase the excretion of water from the body, through the kidneys. there exist several classes of diuretic, and each works in a distinct way. alternatively, an antidiuretic, such as vasopressin (antidiuretic hormone), is an agent or drug which reduces the excretion of water in urine. diureticsdrug classfurosemide 125mg vials for intravenous applicationclass identifiersuseforced diuresis, hypertensionatc codec03