[Vasopressin antagonists].

Vasopressin, like all the other neuro-hormonal systems, is activated in patients with cardiac insufficiency. Vasopressin attaches itself to two distinct specific receptors. It is through the intermediary of the renal V2 receptor, controlling the reabsorption of water by the collecting duct, that vasopressin finely regulates the blood osmolarity. The ubiquitous V1a receptor is essentially responsible for the vasoconstrictor effect of the hormone. Some specific antagonists for these two receptors have now been evaluated in various pathologies such as SIADH, cirrhosis or cardiac insufficiency. In this situation the mixed antagonists, anti-V1a-V2, seem more appropriate than the specific V1a or V2 receptor antagonists. The results of the first human studies are encouraging. The mixed antagonists reduce the pulmonary capillary pressure and increase diuresis and clearance of free water. But further studies are necessary to confirm these results and to demonstrate a reduction in morbidity and mortality before adding this class of medication to the therapeutic arsenal for our patients with cardiac insufficiency.