Early Commencement and Long-Term Continuation of Tolvaptan Treatment Attenuate Functional Impairment of Renal Vasopressin V2 Receptors and Improve Clinical Outcomes in Patients with Heart Failure.

Preserved urinary excretion of aquaporin 2, an index for the function of vasopressin V2 receptor (V2-R), has been reported to predict a favorable response of heart failure patients to treatment with tolvaptan. In this study, we investigated the long-term effects of tolvaptan treatment on clinical outcomes and V2-R function in patients with acute decompensated heart failure (ADHF). We enrolled 90 consecutive patients who were hospitalized in Sapporo Medical University Hospital for ADHF and treated with tolvaptan in the BOREAS-ADHF registry and analyzed patients who continued taking tolvaptan after discharge. The effect of tolvaptan treatment on rehospitalization for HF or death was investigated according to whether the V2-R function was preserved (first morning urine osmolarity ≥ 352 mOsm/L, High-Uosm) or impaired (Uosm < 352 mOsm/L, Low-Uosm). During a median follow-up period of 443 days, significantly fewer patients in the High-Uosm group experienced adverse events than did patients in the Low-Uosm group (P < 0.001). Among the patients with High-Uosm, early commencement of tolvaptan administration (on or before day 7 of hospitalization, Early/High-Uosm) significantly reduced adverse events compared to late administration (after day 7 of hospitalization, Late/High-Uosm). Uosm measured during the long-term follow-up period after discharge was significantly reduced compared to that before commencement of tolvaptan administration in the Late/High-Uosm group (from 468 ± 88 to 395 ± 108 mOsm, -18.3 ± 19.6%, P < 0.05) but not in the Early/High-Uosm group (from 478 ± 115 to 455 ± 133 mOsm, -0.50 ± 35.3%, P = 0.66). These findings indicate that early commencement and long-term continuation of tolvaptan treatment attenuate functional impairment of V2-R and improve clinical outcomes in ADHF patients with preserved V2-R function.

Aquaretics Use in Acute Decompensated Heart Failure (ADHF) Patients: A Literature Review.

This is a literature review of the use of aquaretic in patients with acute decompensated heart failure (ADHF), including the physiologic function of vasopressin and its mechanism of action in heart failure patients, and aquaretic drugs with their respective risks and benefits.Vasopressin is one of several hormones that can cause hyponatremia and worsen congestion in ADHF patients. Aquaretics are a class of drugs that have an antagonistic effect on vasopressin receptors, especially V2R. Aquaretics use in ADHF patients can provide relief for congestive symptoms with no serious adverse effects. In-depth additional understanding regarding aquaretics may be useful for clinical judgments in treating ADHF patients.

Effects of Hydrochlorothiazide and Metformin on Aquaresis and Nephroprotection by a Vasopressin V2 Receptor Antagonist in ADPKD: A Randomized Crossover Trial.

BACKGROUND AND OBJECTIVES: The vasopressin V2 receptor antagonist tolvaptan is the only drug that has been proven to be nephroprotective in autosomal dominant polycystic kidney disease (ADPKD). Tolvaptan also causes polyuria, limiting tolerability. We hypothesized that cotreatment with hydrochlorothiazide or metformin may ameliorate this side effect. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We performed a clinical study and an animal study. In a randomized, controlled, double-blind, crossover trial, we included 13 tolvaptan-treated patients with ADPKD. Patients were treated for three 2-week periods with hydrochlorothiazide, metformin, or placebo in random order. Primary outcome was change in 24-hour urine volume. We also measured GFR and a range of metabolic and kidney injury markers. RESULTS: Patients (age 45±8 years, 54% women, measured GFR of 55±11 ml/min per 1.73 m2) had a baseline urine volume on tolvaptan of 6.9±1.4 L/24 h. Urine volume decreased to 5.1 L/24 h (P<0.001) with hydrochlorothiazide and to 5.4 L/24 h (P<0.001) on metformin. During hydrochlorothiazide treatment, plasma copeptin (surrogate for vasopressin) decreased, quality of life improved, and several markers of kidney damage and glucose metabolism improved. Metformin did not induce changes in these markers or in quality of life. Given these results, the effect of adding hydrochlorothiazide to tolvaptan was investigated on long-term kidney outcome in an animal experiment. Water intake in tolvaptan-hydrochlorothiazide cotreated mice was 35% lower than in mice treated with tolvaptan only. Combination treatment was superior to "no treatment" on markers of disease progression (kidney weight, P=0.003 and cystic index, P=0.04) and superior or equal to tolvaptan alone. CONCLUSIONS: Both metformin and hydrochlorothiazide reduced tolvaptan-caused polyuria in a short-term study. Hydrochlorothiazide also reduced polyuria in a long-term animal model without negatively affecting nephroprotection. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_03_21_CJN11260821.mp3.

Lower Urinary Tract Symptoms: What's New in Medical Treatment?

CONTEXT: Pharmacological treatment is a cornerstone in the management of patients with lower urinary tract symptoms (LUTS). OBJECTIVE: To review emerging evidence in the medical treatment of LUTS. EVIDENCE ACQUISITION: An Embase/Pubmed-based literature search was conducted in December 2017, screening for randomized controlled trials (RCTs), prospective and retrospective series, animal model studies, and reviews on medical treatment of LUTS. EVIDENCE SYNTHESIS: The main medical innovation in recent years in overactive bladder (OAB) has been the approval of the first ß3-adrenoceptor agonists (mirabegron) and intradetrusor onabotulinum toxin A, while several other drugs such as antiepileptics, phosphodiesterase inhibitors, or other ß3-agonists have brought promising results in phase 3 trials. Intraprostatic injections of various drugs for LUTS/benign prostatic hyperplasia have been investigated, but results of phase 3 trials are still pending, while combination therapies of phosphodiesterase type 5 inhibitors+α-blockers or finasteride have been proved as superior to single therapies in RCTs conducted in these patients. Two new formulations of desmopressin have been approved for nocturia in the USA (desmopressin nasal spray) and Europe/Canada/Australia (desmopressin orally disintegrated tablet). Fedovapagon, a vasopressin V2 receptor agonist, has recently completed a large phase 3 trial in male patients with nocturia. Other phase 3 trials are ongoing in bladder pain syndrome (AQX 11-25, a SHIP-1 activator) and in neurogenic detrusor overactivity (mirabegron and abobotulinum toxin A). CONCLUSIONS: Medical treatment of LUTS is a very active research field with recently approved drugs for nocturia (desmopressin acetate nasal spray/orally disintegrated tablet) and numerous emerging drugs currently investigated in OAB, LUTS/benign prostatic hyperplasia, nocturia, bladder pain syndrome, and neurogenic detrusor overactivity. PATIENT SUMMARY: Medical treatment of lower urinary tract symptoms is a very active research field with recently approved drugs for nocturia (desmopressin acetate nasal spray/orally disintegrated tablet) and numerous emerging drugs in overactive bladder, nocturia, neurogenic detrusor overactivity, bladder pain syndrome, or benign prostatic hyperplasia.

Evaluation of lixivaptan in euvolemic and hypervolemic hyponatremia and heart failure treatment.

INTRODUCTION: Lixivaptan is a selective vasopressin type 2 (V2) receptor antagonist that induces aquaresis, the electrolytes sparing excretion of water. Its ability to correct hyponatremia has been demonstrated in experimental animal studies as well as in clinical trials in humans. Recently, three Phase III, double-blind, randomized, placebo-controlled studies have been completed. In two studies, patients with euvolemic hyponatremia were enrolled, one in the inpatient and the other in the outpatient setting and the third study involved patients with hypervolemic hyponatremia hospitalized for decompensated heart failure (HF). The trials confirmed the efficacy of lixivaptan in raising serum sodium but raised concern about its safety in patients hospitalized with decompensated HF. AREAS COVERED: The authors review original publications on lixivaptan and summarize their findings. Specifically, the authors present information regarding its structure, pharmacodynamics and kinetics, metabolism as well as its efficacy and safety in laboratory animals and human studies. Furthermore, the FDA website was accessed to obtain information presented at the September 13, 2012 meeting of the Cardiovascular and Renal Drugs Advisory Committee. EXPERT OPINION: The published data indicate that lixivaptan raises sodium levels in hyponatremic patients and supports its use in patients with euvolemic hyponatremia. However, the authors note that more safety data are still needed specifically in patients with decompensated HF.

Atrial fibrillation or flutter on initial electrocardiogram is associated with worse outcomes in patients admitted for worsening heart failure with reduced ejection fraction: findings from the EVEREST Trial.

BACKGROUND: Heart failure (HF) complicated by atrial fibrillation/flutter (AF/AFL) is associated with worse outcomes. However, the clinical profile and outcomes of patients following hospitalization for HF with AF/AFL on initial electrocardiogram (ECG) has not been well studied. METHODS: EVEREST was a randomized trial of vasopressin-2 receptor blockade, in addition to standard therapy, in 4133 patients hospitalized with HF with ejection fraction ≤40%. A post hoc analysis was performed comparing the clinical characteristics and outcomes [all-cause mortality and cardiovascular mortality/HF hospitalization] of patients with AF/AFL versus sinus rhythm (SR) on baseline ECG, which were centrally analyzed. Times to events were compared using log-rank tests and Cox regression models. RESULTS: Of the 4133 patients, 1195 (29%) were classified with AF/AFL and 2071(50%) with SR. The remaining patients (21%) were excluded because ECGs were unavailable (n = 106), rhythm was paced (n = 727), or junctional/other supraventricular (n = 34). AF/AFL patients were older, with increased weight, faster heart rate, higher blood urea nitrogen, and natriuretic peptide levels compared to SR patients. Anticoagulation was prescribed in 67% of AF/AFL patients on discharge. AF/AFL patients were less likely to receive ß-blockers or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (all P < .05). After risk adjustment, AF/AFL was associated with increased mortality (hazard ratio 1.23; 95% CI, 1.04-1.46) and cardiovascular mortality/HF hospitalization (hazard ratio 1.26; 95% CI, 1.07-1.47). CONCLUSION: AF/AFL on initial ECG in patients hospitalized with HF with reduced ejection fraction is associated with lower use of evidence-based therapies and increased mortality and rehospitalization compared to patients in SR.

Gender does not affect postdischarge outcomes in patients hospitalized for worsening heart failure with reduced ejection fraction (from the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan [EVEREST] Trial).

Women have traditionally been underrepresented in heart failure (HF) trials, and their baseline characteristics and outcomes after hospitalization for HF are unclear. We retrospectively analyzed the clinical characteristics and outcomes of patients according to gender in the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial. EVEREST randomized 4,133 patients hospitalized for HF and ejection fraction of ≤40% to tolvaptan or placebo, in addition to standard therapy. The median follow-up was 9.9 months. Log-rank tests and multivariate Cox regression models were used to compare the hazards of all-cause mortality and cardiovascular mortality or HF hospitalization. Women constituted 1,058 (26%) of the study population. The baseline characteristics were similar except that the women were older with more hypertension and diabetes and less chronic renal insufficiency, previous myocardial infarction, previous coronary revascularization, and baseline defibrillator implantation (all p <0.001). The baseline use of evidence-based HF medical therapies was similar between genders (all p >0.30). Despite a high event rate, no difference was seen in all-cause mortality (men 27% vs women 24%, multivariate hazard ratio 1.04, p = 0.61) or cardiovascular mortality plus HF hospitalization (men 42% vs women 39%, multivariate hazard ratio 1.11, p = 0.10) on univariate analysis or after adjusting for baseline covariates. In conclusion, women hospitalized for worsening HF with an ejection fraction of ≤40% were older, had more hypertension, and had received fewer procedure-based interventions than men but had relatively similar HF medication usage and clinical findings. After hospitalization for HF, women have a similarly high risk of long-term HF morbidity and mortality compared with men.

A comprehensive, longitudinal description of the in-hospital and post-discharge clinical, laboratory, and neurohormonal course of patients with heart failure who die or are re-hospitalized within 90 days: analysis from the EVEREST trial.

Hospitalization for worsening chronic heart failure results in high post-discharge mortality, morbidity, and cost. However, thorough characterization, soon after discharge of patients with early post-discharge events has not been previously performed. The objectives of this study were to describe the baseline, in-hospital, and post-discharge clinical, laboratory, and neurohormonal profiles of patients hospitalized for worsening heart failure with reduced ejection fraction (EF) who die or are re-admitted for cardiovascular (CV) causes within 90 days of initial hospitalization. Retrospective analysis of 4,133 patients hospitalized for worsening heart failure with EF ≤40% in the Efficacy of Vasopressin Antagonism in Heart Failure: Outcome Study with Tolvaptan (EVEREST) trial, which randomized patients to tolvaptan or placebo, both in addition to standard therapy. Clinical and laboratory parameters were obtained within 48 h of admission, during hospitalization, and post-discharge weeks 1, 4, 8, and every 8 weeks thereafter for a median of 9.9 months. Patients with events within 90 days were compared with those with later/no events. All-cause mortality (ACM) and CV re-hospitalization were independently adjudicated. Within 90 days of admission, 395 patients (9.6%) died and 801 patients (19.4%) were re-hospitalized for CV causes. Significant baseline and longitudinal differences were seen between groups with early versus later (>90 days) or no events at 12 months post-randomization. Post-discharge outcomes were similar in the tolvaptan and placebo groups. Patients with early post-discharge events experienced clinically significant worsening in signs and symptoms, laboratory values, and neurohormonal parameters soon after discharge. Identifying these abnormalities may facilitate efforts to reduce post-discharge mortality and re-hospitalization.

The therapeutic use of vaptans for the treatment of dilutional hyponatremia.

Hyponatremia is a very common electrolyte abnormality. Dilutional hyponatremia is very difficult to treat effectively due to the complications of conventional treatment. Arginine-vasopressin (AVP) plays an integral role in circulatory and water homeostasis. AVP is a hormone released in response to increases in plasma tonicity or decreases in plasma volume in an attempt to maintain the plasma osmolality between 284 and 295 mOsm/L. AVP receptor antagonists or "vaptans" are a new class of drugs that allow for the safe and efficacious treatment of dilutional hyponatremia. Conivaptan, a mixed V1a/V2 receptor antagonist, and tolvaptan, a selective V2 receptor antagonist, are the only 2 vaptans approved by the US Food and Drug Administration.

Vasopressin and vasopressin antagonists in heart failure and hyponatremia.

Increased synthesis of arginine vasopressin (AVP) plays a critical role in fluid retention and hyponatremia in patients with heart failure. The AVP receptor antagonists constitute a new class of agents that are promising in the management of hyponatremia and congestion. Three of these agents--conivaptan, tolvaptan, and lixivaptan--have been studied in clinical settings. All are effective in inducing aquaresis (ie, electrolyte-free water excretion) and normalizing serum sodium concentration. They are well tolerated without causing electrolyte disorders, hypotension, or renal impairment. Conivaptan has been approved by the US Food and Drug Administration for short-term intravenous treatment of euvolemic hyponatremia of variable etiology but has not been adequately studied in heart failure. The addition of tolvaptan to standard therapy in hospitalized patients with heart failure has led to symptomatic improvement and decreased body weight, but there is no long-term clinical benefit. Early data on lixivaptan in heart failure suggest a dose-dependent aquaresis effect, and larger studies are under way.

Water in health and disease: new aspects of disturbances in water metabolism.

Vasopressin is a critical regulator of water homeostasis. There are two major receptors for vasopressin: V1 and V2 receptors. Disturbances in water balance are commonly encountered in clinical practice and can be divided into disorders of urinary dilution and concentration. The major representatives of such disorders are diabetes insipidus and the syndrome of inappropriate secretion of antidiuretic hormone (SI ADH). Recent studies show that genetic forms of nephrogenic diabetes insipidus are due to mutations in the genes coding for the vasopressin V2 receptor (V2R) or aquaporin-2 (AQP2). Identification of the genes involved and analysis of the cellular fate of the V2R and AQP2 mutants are relevant for understanding the functioning of the V2R and AQP2 protein. These developments also have implications for future therapeutic options. The development of nonpeptide vasopressin receptor antagonists (VRAs) offers prospects for the treatment of euvolaemic (SI ADH) or hypervolaemic hyponatraemia (congestive heart failure or cirrhosis). Several nonpeptide VRAs are now in various stages of clinical trials. At present, only conivaptan is registered by the FD A for intravenous treatment of euvolaemic and hypervolaemic hyponatremia. A recent long-term study comparing tolvaptan with placebo in patients with chronic heart failure showed no reduction in risk of death and hospitalisation.

Improvement in hyponatremia during hospitalization for worsening heart failure is associated with improved outcomes: insights from the Acute and Chronic Therapeutic Impact of a Vasopressin Antagonist in Chronic Heart Failure (ACTIV in CHF) trial.

BACKGROUND: Hyponatremia predicts poor outcome in patients with acute heart failure syndromes. This study evaluated the relationship between baseline serum sodium, change in serum sodium, and 60-day mortality in hospitalized heart failure patients. METHODS: A post-hoc analysis of the ACTIV in CHF trial was performed. ACTIV in CHF randomized 319 patients hospitalized for worsening heart failure to placebo or one of three tolvaptan doses. Cox proportional hazards regression-analysis was used to explore the relationship between baseline hyponatremia, sodium change during the hospitalization, and 60-day mortality. RESULTS: Hyponatremia was observed in 69 patients (21.6%). After covariate adjustment, baseline hyponatremia was a statistically significant predictor of 60-day mortality (P = 0.0016). Follow-up serum sodium data were available in 68 patients. At hospital discharge, 45 of 68 (66.2%) hyponatremic patients had improvements in serum sodium levels (> or = 2 mmol/l). Hyponatremic patients with a serum sodium improvement had a mortality rate of 11.1% at 60 days post discharge, compared with a 21.7% mortality rate in those showing no improvement. After covariate adjustment, change in serum sodium was a statistically significant predictor of 60-day mortality (HR: 0.736, 95% CI: 0.569-0.952 for each 1-mmol/l increase in serum sodium from baseline). CONCLUSIONS: Serum sodium improvements during hospitalization for heart failure were associated with improved survival at 60 days.

Vasopressin dysregulation: hyponatremia, fluid retention and congestive heart failure.

Arginine vasopressin (AVP) plays a central role in the regulation of water and electrolyte balance. Dysregulation of AVP secretion, along with stimulation of AVP V2 receptors, is responsible for hyponatremia (serum sodium concentration <135 mEq/L) in congestive heart failure (CHF). The stimulation of atrial and arterial baroreceptors in response to hypotension and volume depletion results in the nonosmotic release of AVP. The predominance of nonosmotic AVP secretion over osmotic AVP release plays a key role in the development of water imbalance and hyponatremia in CHF and other edematous disorders. The AVP-receptor antagonists are a new class of agents that block the effects of AVP directly at V2 receptors in the renal collecting ducts. AVP-receptor antagonism produces aquaresis, the electrolyte-sparing excretion of water, thereby allowing specific correction of water and sodium imbalance. This review summarizes recent data from clinical trials evaluating the efficacy and safety of these promising agents for the treatment of hyponatremia.

Vasopressin antagonists in the management of heart failure.

Vasopressin antagonists have been studied in a variety of clinical settings, including patients with acute and chronic heart failure. The clinical trials published to date have sought to describe the clinical and physiologic effects of these agents in an effort to prove clinical efficacy and safety. A variety of agents with varying effects on V2 and V1a vasopressin receptor subtype have been studied. They have been shown to reduce bodyweight and improve serum sodium without worsening renal function. They may also decrease the need for loop diuretic use and may be particularly useful in patients with hyponatremia in the setting of volume overload. Further studies are underway that are powered to assess for morbidity and mortality benefits. The beneficial effects have been well documented but, until outcomes are understood more fully, the use of these agents should be limited to currently approved indications. In the USA, this includes only the treatment of euvolemic hyponatremia.

Evaluation and management of hyponatremia: an emerging role for vasopressin receptor antagonists.

Vasopressin-2 receptor antagonists, collectively known as the 'vaptans', provide a new approach to the treatment of hyponatremia; therefore, an updated Review of the pathophysiology of hyponatremia is particularly timely. After briefly defining hyponatremia and introducing its clinical aspects and complications, we present an approach to the diagnosis and evaluation of hyponatremia that is based primarily on the often-underused concept of free water clearance and, more specifically, the electrolyte-free water clearance. Then we review the use of vasopressin receptor antagonists in the management of hyponatremia from the standpoint of their pharmacology, their mechanism of action, and available efficacy data from clinical trials.

New agents for managing hyponatremia in hospitalized patients.

PURPOSE: An overview of hyponatremia is provided, including its pathophysiology, clinical manifestations, signs and symptoms, and treatment, particularly with arginine vasopressin (AVP)-receptor antagonists. SUMMARY: Hyponatremia (generally defined as a serum sodium concentration of <135 meq/L) is one of the most common electrolyte disorders in hospitalized and clinic patients. It may be caused by a number of conditions, including infections, heart disease, surgery, malignancy, and medication use. Clinical signs and symptoms such as hallucinations, lethargy, weakness, bradycardia, respiratory depression, seizures, coma, and death have been reported. Conventional treatment consists of fluid restriction and administration of hypertonic saline and pharmacologic agents, such as demeclocycline, lithium carbonate, and urea. These treatment options are often of limited effectiveness or difficult for patients to tolerate. AVP promotes the reabsorption of water in the renal collecting ducts by activation of V(2) receptors, resulting in water retention and dilution of serum solutes. The AVP-receptor antagonists, conivaptan, lixivaptan, and tolvaptan, are being studied for the treatment of hyponatremia. Conivaptan has been shown in clinical trials to increase free-water excretion and safely normalize serum sodium concentrations in patients with hyponatremia and is well tolerated. Also in clinical trials, lixivaptan and tolvaptan have safely improved serum sodium concentrations in patients with hyponatremia. CONCLUSION: Hyponatremia is a serious health condition for which treatment should be carefully performed. As new agents for treating hyponatremia, AVP-receptor antagonists have demonstrated efficacy and safety in clinical trials and may serve as significant improvements in the current treatment options for managing this disorder.

Treatment of congestive heart failure: present and future.

The treatment of patients with congestive heart failure has markedly improved over the past 25 years. The most successful therapy has been attenuation of neurohumoral overactivation with antagonists of the renin-angiotensin-aldosterone system, as well as beta-adrenergic blockade. Cardiac surgical interventions, which include not only aortocoronary artery bypass surgery but also interventions that remodel the heart and repair the mitral valve, have also been advocated. However, randomized clinical trials to prove their benefit and to identify which patients could derive the most benefit from these interventions are lacking. Cardiac devices, such as biventricular pacemakers (for cardiac resynchronization) and implantable cardiac defibrillators, have proved useful in improving survival and quality of life. The treatment of sleep apnea with continuous positive airway pressure has shown some promise, as has immune modulation therapy, but more research to conclusively prove their efficacy is necessary. Cell therapy with skeletal myoblasts or pluripotential stem cells is an interesting and emerging area of research that shows enormous promise. However, fundamental questions regarding the optimal use of this therapy remain unanswered. Finally, although exciting, these developments, along with the changing demographics of the Canadian population, will require a change in the way we provide care for patients with congestive heart failure. These changes will require greater involvement of health care professionals other than physicians, and greater emphasis on outpatient care, early detection and prevention, and evidence-based practice.

The central vasopressinergic system: examining the opportunities for psychiatric drug development.

Arginine vasopressin (AVP) is a cyclic nonapeptide synthesized exclusively by neurosecretory cells of the central nervous system (CNS). Two functionally distinct vasopressinergic systems can be defined based on differences in the sites of action and release of AVP. The peripheral vasopressinergic system encompasses the sites of action for AVP released into peripheral circulation (e.g. vascular smooth muscle, liver, kidney) from nerve terminals in the posterior pituitary. Peripherally circulating AVP is responsible for the classic endocrine functions ascribed to this neurohormone (e.g. vasoconstriction, glycogen metabolism, antidiuresis). The central vasopressinergic system, on the other hand, includes the sites of AVP synthesis and release within the CNS, where AVP acts as a neuromodulator/neurotransmitter regulating an array of CNS-mediated functions (e.g. learning and memory, neuroendocrine reactivity, social behaviors, circadian rhythmicity, thermoregulation, and autonomic function). Historically, pharmaceutical interest has focused on drug development efforts that sought to exploit the peripheral effects of AVP. Evidence, however, from clinical studies and animal models of CNS disorders has directly implicated disturbances in vasopressinergic activity in the pathophysiology of a number of human psychiatric disorders (mood, anxiety, and cognitive disorders). This review will examine the available evidence of central vasopressinergic system involvement in psychiatric disorders, and the potential opportunities for development of novel psychopharmaceuticals around this system will be discussed. Specific lines of evidence will be presented which rationalize each AVP receptor subtype (V(1)R or V(1a), V(2)R, V(3)R or V(1b)) as a molecular target for particular psychiatric indications.