Scientists have developed a new class of drugs called the vaptans that could treat a large variety of conditions, including but not limited to painful menstrual periods, brain hemorrhage, certain psychotic disorders, and glaucoma. This was reported by Professor Guy Decaux, Erasmus University Hospital, Brussels, Belgium, and colleagues in a New Drug Class paper released on May 9, 2008 in The Lancet.

The vasopressin-receptor antagonists, dubbed vaptans, target the vasopressin hormonal feedback system. Vasopressin, also called ant-diuretic hormone or ADH, is an important part of regulation in the circulatory system and is integral to the balance of water in the body. As a fundamental part of hormonal control in the body, it is implicated in many different conditions. Vaptans can be administered orally or intravenously. They work by competing for the active sites on cells meant for vasopressin binding — in this way, the vasopressin is blocked from acting, which earns them the title of vasopressin antagonists.

There are several subclasses of vaptan which are in development or complete. For one, relcovaptan has been tested in the treatment of several ailments: painful menstrual periods, known as dysmenorrhea; Raynaud’s disease, a vascular disorder that sometimes restricts blood flow to the extremities; and tocolysis, when premature labor leads to premature birth.

Another subclass of vaptans, which targets a different cell receptor site, encompasses several drugs including mozavaptan, lixivaptan, satavaptan, and tolvaptan, all inducing water loss without the loss of mineral salts, which often accompanies other diuretics. These drugs are used to treat hyponatraemia, or sodium deficiency. Presently, conivaptan is the only vaptan approved by the FDA for treatment of this condition. Many from this category of drugs is also in development to treat several other problems, including renal failure in polycystic kidney disease, diabetic nephropathy, cirrhosis, and depression.

Finally, vaptans have been studied with promising results for the treatment of glaucoma, the inner-ear disorder Meniere’s disease, brain hemorrhage, and small cell cancers.

Non-peptide arginine-vasopressin antagonists: the vaptans
Guy Decaux, Alain Soupart, Gilbert Vassart
The Lancet, Vol 371, May 10, 2008
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Written by Anna Sophia McKenney