Employment of vasopressin receptor antagonists in management of hyponatraemia and volume overload in some clinical conditions.
OBJECTIVE
Hyponatraemia, the most common electrolyte imbalance occurring in hospitalized subjects, is usually classified as hypovolaemic, euvolaemic or hypervolaemic. Hyponatraemia is a predictor of death among subjects with chronic heart failure and cirrhosis. The inappropriate secretion of the antidiuretic hormone (AVP) seems to be of pivotal importance in the decline of serum sodium concentration in these clinical conditions. The objective of this review was to summarize recent progress in management of hyponatraemia in SIADH, cirrhosis and heart failure.


METHODS
Literature searches were conducted on the topics of hyponatraemia and vasopressin receptor antagonists, using PubMed, pharmaceutical company websites and news reports. The information was evaluated for relevance and quality, critically assessed and summarized.


CONCLUSIONS
The initial treatment of severe hyponatraemia is directed towards the prevention or management of neurological manifestations and consists of an intravenous infusion of hypertonic saline. Fluid restriction is indicated in oedematous states. Diuretics alone or in combination with other specific drugs remain the main strategy in the management of volume overload in heart failure. In resistant cases, ultrafiltration can lead to effective removal of isotonic fluid preventing new episodes of decompensation; however, aquapheresis is associated with increased costs and other limits. In several trials, the efficacy of vasopressin receptor antagonists in euvolaemic patients (inappropriate antidiuretic hormone secretion) or in hypervolaemic hyponatraemia (chronic heart failure, cirrhosis) has been evaluated. It was found that vaptans, which promote aquaresis, were superior to a placebo in raising and maintaining serum sodium concentrations in these subjects.


CONCLUSIONS
Combined with conventional therapy, vasopressin receptor antagonists (AVP-R antagonists) are able to increase the excretion of electrolyte-free water and the sodium concentration. Further studies are needed to assess efficacious outcomes of aquaresis compared with aquapheresis and with conventional therapy.
Dipartimento Biomedico di Medicina Interna e Specialistica, Universitá di Palermo, Palermo, Italy.
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Urso
Dipartimento Biomedico di Medicina Interna e Specialistica, Universitá di Palermo, Palermo, Italy.
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Brucculeri
Dipartimento Biomedico di Medicina Interna e Specialistica, Universitá di Palermo, Palermo, Italy.
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Caimi
D065092:Antidiuretic Hormone Receptor Antagonists / Q000627:therapeutic use*; D006333:Heart Failure / Q000188:drug therapy / Q000503:physiopathology; D006801:Humans; D007010:Hyponatremia / Q000188:drug therapy* / Q000209:etiology; D007177:Inappropriate ADH Syndrome / Q000188:drug therapy / Q000503:physiopathology; D008103:Liver Cirrhosis / Q000188:drug therapy / Q000503:physiopathology; D012964:Sodium / Q000097:blood
D065092:Antidiuretic Hormone Receptor Antagonists; D012964:Sodium
AVP; AVP-receptor antagonists; aquaresis; cirrhosis; heart failure; hyponatraemia