An aquaretic is a novel class of drug that is used to promote aquaresis, the excretion of water without
electrolyte
An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solven ...
loss. Strictly speaking, aquaretics are not
diuretic
A diuretic () 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 ...
s but are sometimes classified as such.
Aquaresis is preferable to
diuresis
Diuresis () is the excretion of urine, especially when excessive (polyuria). The term collectively denotes the physiologic processes underpinning increased urine production by the kidneys during maintenance of fluid balance.
In healthy people, ...
in the treatment of
hyponatremia
Hyponatremia or hyponatraemia is a low concentration of sodium in the Serum (blood), blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. Symp ...
.
Pharmacokinetics
Aquaretics increase urine output without increasing
sodium
Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
and
chloride
The term chloride refers to a compound or molecule that contains either a chlorine anion (), which is a negatively charged chlorine atom, or a non-charged chlorine atom covalently bonded to the rest of the molecule by a single bond (). The pr ...
excretion, thus causing an increase in urine whilst retaining
electrolytes
An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble salts, acids, and bases, dissolved in a polar solvent like water. Upon dissolving, t ...
.
Examples
A number of herbal medicines are classified as aquaretics, for example
common horsetail or
common nettle leaves.
Synthetic aquaretics are
vasopressin receptor antagonists and include
conivaptan
Conivaptan, sold under the brand name Vaprisol, is a non-peptide inhibitor of the receptor for anti-diuretic hormone, also called vasopressin. It was approved in 2004 for hyponatremia (low blood sodium levels). Additionally, Conivaptan is used ...
,
tolvaptan,
demeclocycline, and
mozavaptan (OPC-31260), as well as
lithium
Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...
. Conivaptan hydrochloride and tolvaptan have been approved by the FDA for treating
syndrome of inappropriate antidiuretic hormone.
Mozavaptan is approved in Japan.
References
Diuretics
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