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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite diuretics being used to relieve the fluid retention/congestion associated with heart failure (HF), patients with HF are commonly hospitalised due to progressive volume retention with an increase in body weight and the deterioration of symptoms. Arginine vasopressin acts at vasopressin V2 receptors in the kidney as an antidiuretic. Tolvaptan is an orally-active selective V2-receptor antagonist. In the Acute and Chronic Therapeutic Impact of a Vasopressin antagonist in Congestive Heart Failure trial of patients hospitalised with HF, tolvaptan 30 mg/day increased urine volume and induced a weight loss of 3.3 kg at discharge (placebo; 1.9 kg). In post hoc analyses, mortality was lower with tolvaptan in patients with renal impairment and severe congestion, compared to placebo. Thus, it seems that tolvaptan is an advancement in the treatment of severely decompensated HF.
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PMID:Is vasopressin-receptor antagonism an advancement in the treatment of heart failure? 1511 14

Current therapies for acute heart failure syndromes (AHFS) target hemodynamics by decreasing congestion or increasing myocardial contraction. Several new agents for AHFS use novel mechanisms of action that focus on new treatment targets, such as those providing anti-ischemic and anti-stunning effects, blocking vasopressin receptors, or blocking endothelin-1 receptors. For example, levosimendan acts as a calcium sensitizer and adenosine triphosphate-dependent potassium (K(ATP)) channel opener that increases contraction, causes vasodilation, and provides cardioprotective effects. This is accomplished by its dual mechanism of action. Levosimendan binds to cardiac troponin C, thereby enhancing calcium myofilament responsiveness and increasing myocardial contraction without increasing intracellular calcium levels. Thus, contraction is increased with no significant increase in myocardial oxygen consumption. The opening of K(ATP) channels by levosimendan causes vasodilation and exerts anti-ischemic and anti-stunning effects on the myocardium. Other new agents target neurohormonal pathways. Tezosentan is an antagonist of endothelin-1 receptors A and B. By inhibiting endothelin-1 receptors, tezosentan may counteract the activities of endothelin-1, which include vasoconstriction, proarrhythmic activities, potentiation of other neurohormones, and mediation of increased vascular permeability. Tolvaptan is a vasopressin V2-receptor antagonist that functions as an aquaretic (ie, it increases urine volume and serum sodium with little or no sodium loss). Therefore, by using novel mechanisms of action, these agents may provide new opportunities for helping patients with AHFS.
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PMID:Pharmacology of new agents for acute heart failure syndromes. 1618 25

Diuretics are frequently required to treat fluid retention in patients with congestive heart failure (CHF). Unfortunately, they can lead to a decline in renal function, electrolyte depletion, and neurohumoral activation. Arginine vasopressin (AVP) promotes renal water reabsorption via the V2 receptor, and its levels are increased in CHF. This study was designed to assess the effects of a single oral dose of tolvaptan, a selective V2-receptor blocker, in the absence of other medications, on renal function in human CHF and to compare this to the effects of a single oral dose of furosemide. We hypothesized that V2-receptor antagonism would yield a diuresis comparable to furosemide but would not adversely affect renal hemodynamics, plasma electrolyte concentration, or neurohumoral activation in stable human CHF. Renal and neurohumoral effects of tolvaptan and furosemide were assessed in an open-label, randomized, placebo-controlled crossover study in 14 patients with NYHA II-III CHF. Patients received placebo or 30 mg of tolvaptan on day 1 and were crossed over to the other medication on day 3. On day 5, all subjects received 80 mg of furosemide. Tolvaptan and furosemide induced similar diuretic responses. Unlike tolvaptan, furosemide increased urinary sodium and potassium excretion and decreased renal blood flow. Tolvaptan, furosemide, and placebo did not differ with respect to mean arterial pressure, glomerular filtration rate, or serum sodium and potassium. We conclude that tolvaptan is an effective aquaretic with no adverse effects on renal hemodynamics or serum electrolytes in patients with mild to moderate heart failure.
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PMID:Vasopressin-2-receptor antagonism augments water excretion without changes in renal hemodynamics or sodium and potassium excretion in human heart failure. 1618 91

Fluid retention and extracellular volume expansion are frequently encountered complications of congestive heart failure (HF) that can cause morbidity and mortality. Tolvaptan (Otsuka) is an orally administered nonpeptide vasopressin (VP) V2 receptor antagonist that inhibits water reabsorption in the kidney by competitively blocking VP binding, resulting in water diuresis without significantly changing total electrolyte excretion. In the 24-hour period following a 30-mg dose of tolvaptan, urine excretion rate increases and declines as plasma concentrations rise and fall; this uneven effect results in 80% of daily urine output in the first 12 hours. Therefore, the current study was designed to assess the pharmacodynamic effects, pharmacokinetics, and clinical safety of tolvaptan 30 mg QD plus placebo versus 15 mg BID over 7 days in patients with NYHA Class II/III heart failure and persistent fluid overload, SBP > or = 90 mm Hg, and a serum creatinine < or = 3.0 mg/dL. Patients were withdrawn from diuretics for 48 hours before randomization. Statistics were performed with ANCOVA for continuous variables and Mantel-Haenszel mean score test stratified by center for categorical variables. Thirty-nine of 40 patients completed days 1 and 7. There were no significant clinical, pharmacokinetic, or pharmacodynamic differences between the dosing regimens over time. Based on these findings, tolvaptan 30 mg was chosen as the comparator for placebo in a large phase 3 survival trial.
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PMID:Comparison of two doses and dosing regimens of tolvaptan in congestive heart failure. 1622 67

Diuretics interfere with the sodium retention of heart failure by inhibiting the reabsorption of sodium in the renal tubes, increase urine output and decrease physical signs of fluid retention in patients with heart failure (HF). Diuretics are the only drugs used for the treatment of HF that can adequately control the fluid retention of HF. Loop diuretics, potassium-sparing agents and thiazides are used for treatment. Tolvaptan, vasopressin receptor antagonists, is a new drug and long-term clinical trials are under way to determine the role. The use of inappropriate doses of diuretics will lead to result in fluid retention, renal insufficiency with ACE inhibitors and ARBs, increase the risk of treatment with beta blockers or volume contraction, increase the risk of hypotention and diminish the response to ACE inhibitors and ARBs. Appropriate use of diuretics is important in the success of the treatment of HF.
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PMID:[Diuretics]. 1668 77

Arginine vasopressin (AVP) is a neuropeptide hormone that plays an important role in circulatory and sodium homeostasis, and regulating serum osmolality. Several clinical conditions have been associated with inappropriately elevated levels of AVP including heart failure, cirrhosis of the liver and the syndrome of inappropriate secretion of antidiuretic hormone. Three receptor subtypes that mediate the actions of AVP have been identified (V(1A), V(2) and V(1B)). Activation of V(1A) receptors located in vascular smooth muscle cells and the myocardium results in vasoconstriction and increased afterload and hypertrophy. The V(2) receptors located primarily in the collecting tubules mediate free water absorption. The V(1B) receptors are located in the anterior pituitary and mediate adrenocorticotropin hormone release. The cardiovascular and renal effects of AVP are mediated primarily by V(1A) and V(2) receptors. Antagonism of V(1A) receptors results in vasodilatation and antagonism of V(2) receptors resulting in aquaresis, an electrolyte-sparing water excretion. Several non-peptide AVP antagonists (vasopressin receptor antagonists [VRAs]) also termed 'vaptans' have been developed and are vigorously being studied primarily for treating conditions characterised by hyponatraemia and fluid overload. Conivaptan is a combined V(1A)/V(2)-receptor antagonist that induces diuresis as well as haemodynamic improvement. It has been shown in clinical trials to correct euvolaemic and hypervolaemic hyponatraemia, and has been approved by the US FDA for the treatment of euvolaemic hyponatraemia as an intravenous infusion. Tolvaptan, a selective V(2)-receptor antagonist, has undergone extensive clinical studies in the treatment of hyponatraemia and heart failure. It has been shown to effectively decrease fluid in volume overloaded patients with heart failure and to correct hyponatraemia. A large outcome study (n = 4133 patients) will define its role in the management of heart failure. Lixivaptan and satavaptan (SR-121463) are other selective V(2)-receptor antagonists being evaluated for the treatment of hyponatraemia. In addition, a potential role for the vaptans in attenuating polyuria in nephrogenic diabetes insipidus and cyst development in polycystic kidney disease is being explored. Ongoing clinical trials should further define the scope of the potential therapeutic role of VRAs.
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PMID:Therapeutic potential of vasopressin receptor antagonists. 1742 3

Tolvaptan is an orally effective nonpeptide arginine vasopressin (AVP) V(2)-receptor antagonist synthesized by Otsuka Pharmaceutical Co., Ltd. In in vitro receptor-binding studies, tolvaptan blocked the binding of [(3)H]AVP to human V(2) receptors with 29-fold greater selectivity than that for V(1a) receptors, and showed no inhibition of V(1b) receptors. Tolvaptan inhibited not only the binding of [(3)H]AVP but also the AVP-induced production of cyclic AMP in human V(2)-receptor-expressing HeLa cells. In addition, tolvaptan has no intrinsic V(2) receptor agonistic effect. In in vivo studies, tolvaptan showed marked aquaresis in healthy and diseased animals. In rat models with acute and chronic hyponatremia, tolvaptan improved hyponatremia, resulting in the prevention of death, and improved organ water retention. Tolvaptan reduced cardiac preload without unfavorable effects on renal functions, systemic hemodynamics, or circulating neurohormones in dogs with heart failure (HF). Furthermore, in animal models of human polycystic kidney disease (PKD), tolvaptan showed a decrease in kidney weight as well as in cyst and fibrosis volume. In clinical trials including the "ACTIV in CHF" study, tolvaptan in addition to standard therapy increased fluid loss resulting in decreased body weight, and improved edema and serum sodium without affecting blood pressure, heart rate, or renal functions in patients with HF. In patients with hyponatremia, treatment with tolvaptan without fluid restriction appeared to be more effective than fluid restriction alone at correcting hyponatremia without an increase in adverse events. A phase III trial EVEREST is currently being conducted to evaluate the long-term efficacy and safety of tolvaptan in hospitalized patients with severe HF. In conclusion, tolvaptan offers the possibility of a useful therapy in hyponatremia, congestive heart failure, and various other diseases that are associated with volume overload. Furthermore, tolvaptan is also expected to be effective in the treatment of PKD.
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PMID:Tolvaptan, an orally active vasopressin V(2)-receptor antagonist - pharmacology and clinical trials. 1744 84

Diuretics are frequently required to treat fluid retention in patients with chronic heart failure (CHF). Unfortunately, they can lead to a decline in renal function, electrolyte depletion, and neurohormonal activation. Arginine vasopressin (AVP) promotes renal water reabsorption via the V(2) receptor (V(2)R) and its levels are increased in CHF. This study was conducted to characterize the diuretic effect of tolvaptan, a non-peptide AVP V(2)R antagonist, and furosemide, a loop diuretic in a rat model of CHF after experimental autoimmune myocarditis. CHF was elicited in Lewis rats by immunization with porcine cardiac myosin, and 28 days after immunization rats were treated for 28 days with oral tolvaptan, and furosemide. CHF was characterized by left ventricular remodeling and impaired systolic and diastolic function. Tolvaptan produces a diuresis comparable to furosemide. Unlike tolvaptan, furosemide significantly increased urinary sodium and potassium excretion. Tolvaptan markedly elevated electrolyte-free water clearance (E-CH(2)O) or aquaresis to a positive value and increased urinary AVP excretion. In contrast to tolvaptan, furosemide elevated only electrolyte clearance (E-Cosm) but not E-CH(2)O. The differences in diuretic profile reflected the changes in plasma sodium and hormone levels. Tolvaptan dose dependently elevated plasma sodium concentration, but furosemide tended to decrease it. Furosemide significantly elevated plasma renin activity and aldosterone concentration. On the other hand, tolvaptan did not affect these parameters. Our results suggest that, tolvaptan have a potential medical benefit for the treatment of edematous conditions in CHF by removing excess water from the body without activating the RAAS or causing serum electrolyte imbalances.
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PMID:Effects of V2-receptor antagonist tolvaptan and the loop diuretic furosemide in rats with heart failure. 1817 82

Acute decompensated heart failure accounts for more than 1 million hospitalizations in the USA every year. Currently, the most common treatment for symptom relief is the use of loop diuretics, despite recent concerns for potential adverse effects. With the growing understanding of the role of neurohormonal dysregulation in the pathophysiology of heart failure, there has been increasing interest in novel pharmacologic therapies targeting specific neurohormonal axes. Serum arginine vasopressin is a potent vasoconstrictor, as well as an antidiuretic, and serum concentrations are upregulated in heart failure. Tolvaptan, a vasopressin receptor antagonist, has been shown to improve diuresis and symptom relief without adversely affecting renal function, and may be a promising novel therapeutic agent in the growing population of patients with heart failure.
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PMID:Role of tolvaptan in acute decompensated heart failure. 1851 Apr 77

Acute heart failure syndromes are a common cause of emergency department visits and hospitalization in North America and Europe. Although in-hospital mortality is relatively low, the postdischarge mortality and rehospitalization rates can be as high as 10-15 and 30%, respectively, within 60-90 days following discharge. It appears that the main reason for admission and readmission for heart failure is related to congestion manifested by dyspnea, jugular venous distension and edema. Often, congestion is associated with dilutional hyponatremia that is difficult to treat. Hyponatremia is an important predictor of increased mortality and the available therapies to treat congestion and/or hyponatremia are often ineffective and/or unsafe. Accordingly, there is an unmet need to develop a new agent that effectively relieves congestion due to high filling pressure without worsening renal function and improving or normalizing serum sodium in hyponatremic patients. This paper provides an overview of a new compound, tolvaptan, an oral selective V(2)-vasopressin antagonist in light of the recently published Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial. The biochemical and pharmacological properties are discussed in conjunction with its clinical efficacy and safety, exploring the potential role of tolvaptan in the management of acute heart failure syndromes presenting with or without hyponatremia.
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PMID:EVEREST study: Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan. 1901 85


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