<prompt> Tolvaptan is used for:SIADHCentral DIVon Willebrand diseaseCatecholamine resistant shock  <response>: Ans. A SIADHRef: Harrison 20th302Vaptans like tolvaptan are vasopressin receptor antagonists.V1 receptor antagonists may be useful when total peripheral resistance is increased e.g. CHF and hypertension whereas V2 antagonists may be useful for the treatment of SIADH.Relcovaptan is selective V1 antagonist whereas lixivaptan, mozavaptan and tolvaptan are V2 selective antagonists.Conivaptan is V1aV2 receptor antagonist used as an aquaretic increase water excretion without affecting electrolytes like sodium in CHF.Conivaptan is administered by i.v. injection whereas lixivaptan and tolvaptan can be given orally. 