Tolvaptan is a selective and competitive arginine vasopressin receptor 2 antagonist. Vasopressin acts on the V2 receptors found in the walls of the vasculature and luminal membranes of renal collecting ducts. By blocking V2 receptors in the renal collecting ducts, aquaporins do not insert themselves into the walls thus preventing water absorption. This action ultimately results in an increase in urine volume, decrease urine osmolality, and increase electrolyte-free water clearance to reduce intravascular volume and an increase serum sodium levels. Tolvaptan is especially useful for heart failure patients as they have higher serum levels of vasopressin. Tolvaptan is used to treat low blood sodium levels (hyponatremia) associated with various conditions like congestive heart failure, cirrhosis, and syndrome of inappropriate antidiuretic hormones (SIADH). FDA approved on May 19, 2009. Tolvaptan is sold under the trade names Samsca and Jinarc.

Conivaptan is an arginine vasopressin (AVP) receptor antagonist with affinity for AVP receptor subtypes V1A and V2. The antidiuretic action of AVP is mediated through activation of the V2 receptor, which functions to regulate water and electrolyte balance at the level of the collecting ducts in the kidney. Conivaptan was approved in 2004 for hyponatremia caused by syndrome of inappropriate antidiuretic hormone. Conicaptan is being evaluated for reduce intracranial pressure in patients with traumatic brain injury, and as a treatment for heart failure.

Desmopressin is a chemical that is similar to Antidiuretic Hormone (ADH), which is found naturally in the body and is produced by the hypothalamus and stored, in the posterior pituitary gland. The main function of ADH is to regulate extracellular fluid volume in the body. ADH secretion is stimulated by angiotensin II, linking it to the renin-angiotensin-aldosterone system (RAAS). ADH stimulates water reabsorption in the kidneys by causing the insertion of aquaporin-2 channels on the apical surface of cells of the distal convoluted tubule and collecting tubules. Desmopressin also causes vasoconstriction through its action on vascular smooth muscle cells of the collecting tubules. It increases urine concentration and decreases urine production. Acetate salt of desmopressin is sold under brand name DDAVP with different formulations: DDAVP Nasal Spray is indicated as antidiuretic replacement therapy in the management of central cranial diabetes insipidus and for management of the temporary polyuria and polydipsia following head trauma or surgery in the pituitary region. It is ineffective for the treatment of nephrogenic diabetes insipidus. DDAVP Injection is indicated for patients with hemophilia A with factor VIII coagulant activity levels greater than 5% and is indicated for patients with mild to moderate classic von Willebrand’s disease (Type I) with factor VIII levels greater than 5%. It was suggested that desmopressin-induced relaxation was mediated by a receptor subtype sharing both V1A and V2 pharmacological profiles.

Relcovaptan is a potent, orally active nonpeptide vasopressin V1a antagonist that was undergoing clinical development with Sanofi-Synthélabo (formerly Sanofi) in France. SR49059 is specifically and selectively antagonizes the effect of vasopressin on the V1a receptor in animals’ and in humans. The drug has been shown to have an excellent safety profile in single and repeated dose toxicological studies in animals. In the human uterus in vitro, SR49059 caused a dose-dependent inhibition of vasopressin V1a receptor-mediated activity of myometrial strips and isolated uterine arteries. In vivo in nonpregnant women, an inhibition of vasopressin-induced uterine activity has been observed.

Ribuvaptan (BAY 868050) is a vasopressin receptor antagonist that has been developed for treatment of heart failure. No information on current use is available.

Lixivaptan is an orally-active, vasopressin 2 receptor antagonist. It is indicated for the treatment of symptomatic hypervolemic and euvolemic hyponatremia, associated with heart failure (HF) and syndrome of inappropriate antidiuretic hormone (SIADH). Adverse events likely to be result of the pharmacologic action of lixivaptan are: constipation, dry mouth, dizziness, insomnia. Grapefruit juice significantly increased the extent of lixivaptan absorption as compared to lixivaptan administered under fasted conditions but not under fed conditions. Lixivaptan Cmax and AUC∞ increased by 2.4-fold and 3.2-fold, respectively, when lixivaptan was administered with ketoconazole (the same in case of Simvastatin).

Sanofi-Synthélabo has developed satavaptan (previously known as SR121463) as a non-peptidic vasopressin V2 receptor antagonist for the potential treatment for cardiovascular indications such as congestive heart failure (CHF) and hypertension. The drug reached phase II for these indications before the studies were discontinued. Satavaptan was also studied for the potential treatment of glaucoma. In addition, this drug was involved in phase III clinical trials in patients with ascites due to cirrhosis of the liver and in in patients with dilutional hyponatremia. However, the further development of the satavaptan was discontinued in 2009.

Nelivaptan is a selective, orally active, non-peptide vasopressin receptor antagonist selective for the V1B subtype. It showed promise in preclinical animal models and advanced to phase II clinical trials for the treatment of anxiety and depression; however, in 2008, Sanofi-Aventis announced that further development of this drug had been halted.

Ornipressin (ornithine-8-vasopressin, POR-8), is a synthetic vasopressin analogue. Ornipressin produces vasoconstriction via vasopressin V1A receptor-mediated vascular smooth muscle cell contraction. Ornipressin is used to control bleeding in surgical practice. It was introduced in 1971, and approved for use in Germany, Switzerland, New Zealand and Australia.

Mozavaptan hydrochloride was approved by Pharmaceuticals and Medical Devices Agency of Japan (PMDA) on July 26, 2006. It was developed and marketed as Physuline® by Otsuka in Japan. Mozavaptan hydrochloride is a vasopressin receptor antagonist. It is indicated for the treatment of hyponatremia due to excessive fluid retention when restriction of fluid intake is ineffective. Physuline® is available as film-coated tablet for oral use, containing 30 mg of Mozavaptan hydrochloride. The recommended dose is one tablet (30 mg) once daily after a meal.