Nephrogenic diabetes insipidus is a disease of the kidney that impairs water conservation. The kidney is unable to respond to the antidiuretic hormone arginine vasopression, according to the Nephrogenic Diabetes Insipidus Foundation. Normally, the kidney responds to arginine vasopressin and conserves water for the body. In nephrogenic diabetes insipidus, because the kidney is insensitive to the antidiuretic hormone, large volumes of water are lost and the patient is constantly thirsty and in danger of dehydration. Several medications are used to treat nephrogenic diabetes insipidus.
Thiazide Diuretics
Because a patient with nephrogenic diabetes insipidus excretes large volumes of dilute urine, thiazide diuretics can help. Dilute urine means urine without any soluble substances. Normally, urine contains some electrolytes, such as potassium and sodium, as well as other minerals. The dilute urine of a patient with diabetes insipidus contains very little soluble material. Thiazide diuretics can help the kidney excrete sodium into the urine, making it more concentrated. The downside to thiazide diuretics, such as hydrochlorathiazide, is they also influence potassium excretion and can cause very low potassium levels in the body. This can have dangerous effects on the heart. This side effect can be prevented by using potassium supplements.
Indomethacin
In patients with nephrogenic diabetes insidipidus, the E2 prostaglandin is increased. Prostaglandin E2 decreases the ability of the kidney to absorb water. Indomethacin is a prostaglandin blocker. A 2000 study published in the Oxford Journals noted that indomethacin potentiates the effect of thiazide diuretics. The authors postulate that the thiazide diuretics work on the inside of the kidney filtering system and that indomethacin works on the outside of the filter by blocking prostaglandin E2. The Nephrogenic Diabetes Insipidus Foundation notes that the use of indomethacin can cause serious gastrointestinal upset and gastrointestinal bleeding.
Amiloride
The use of lithium in psychiatric patients is a common cause of nephrogenic diabetes insipidus because lithium accumulates in the kidney filtering systems. The use of amiloride inhibits the accumulation of lithium in the kidney. Amiloride also is a potassium-sparing diuretic, which means there is less potassium spilled into the urine than with a thiazide diuretic. In some patients, both a thiazide diuretic and amiloride are used together. In order for any diuretic to be effective in diabetes insipidus, patients must adhere to a low-sodium diet.
